Mainframe Glossary
1830 Terms Explained
Your comprehensive reference guide to mainframe terminology, technologies, and concepts
A
ABEND
An unexpected termination of a program or job due to an error condition. Common in batch processing environments where jobs fail before completion....
Access Method
The technique used by programs to store and retrieve data from storage devices. Access methods define how data is organized, accessed, and managed on ...
ACF2
A comprehensive security software package from Broadcom (formerly CA Technologies) that provides authentication, authorization, and auditing capabilit...
ADABAS
A high-performance, inverted-list database management system from Software AG, designed for high-volume transaction processing and optimized for the N...
APF
A z/OS security mechanism that identifies programs authorized to use restricted system functions, access protected datasets, and execute privileged op...
APL
An array-oriented programming language developed by Kenneth Iverson, known for its concise mathematical notation and powerful array manipulation capab...
Application Server
Middleware software that provides a runtime environment for business applications, managing transactions, connections between user interfaces and data...
ASCII
A character encoding standard using 7 or 8 bits to represent text characters, widely used in modern computing systems including UNIX, Linux, Windows, ...
ASM
A low-level programming language that provides a one-to-one correspondence between mnemonic operation codes and machine language instructions. On main...
Address Space
A virtual storage area assigned to a program or task, providing isolation between different executing programs. Each address space has its own private...
Address Space Identifier
A unique numeric identifier assigned to each address space in a z/OS system, analogous to a UNIX Process ID (PID). The ASID enables the system to dist...
ABEND - Abnormal End of Task
An ABEND (Abnormal End) signifies the unplanned termination of a program, task, or job on an IBM z/OS system due to an error condition. It indicates t...
ACRB - Access Control Rule Base
An Access Control Rule Base (ACRB) is a comprehensive set of rules and policies that define and govern access permissions to resources within an IBM z...
ACS - Automatic Class Selection
Automatic Class Selection (ACS) is a critical component of **DFSMS (Data Facility Storage Management Subsystem)** on z/OS that automates the assignmen...
Active Log
In the context of IBM z/OS database systems like DB2 for z/OS and IMS DB/DC, the Active Log refers to the set of primary log datasets currently being ...
ADSP - Automatic Data Set Protection
Automatic Data Set Protection (ADSP) is a security feature within IBM's Resource Access Control Facility (RACF) for z/OS that automatically protects n...
ALC - Assembler Language Coding
Assembler Language Coding (ALC) refers to programming in IBM's Assembler language, a low-level programming language that provides a symbolic represent...
Alias
In z/OS, an alias is an alternative name assigned to a dataset, a member within a partitioned dataset (PDS or PDSE), or a catalog entry. It serves as ...
Allocation
In the z/OS environment, **allocation** refers to the process of assigning system resources—such as datasets, I/O devices (tape drives, printers), mem...
AMS - Access Method Services
Access Method Services (AMS), executed via the `IDCAMS` utility program, is the primary tool on z/OS for defining, deleting, altering, listing, and ma...
APF - Authorized Program Facility
APF, or Authorized Program Facility, is a crucial security mechanism in z/OS that identifies programs authorized to use sensitive system services and ...
API - Application Programming Interface
An Application Programming Interface (API) is a set of defined methods, routines, protocols, and tools for building software applications. In the main...
APPC - Advanced Program-to-Program Communication
Advanced Program-to-Program Communication (APPC) is a peer-to-peer communication protocol within IBM's Systems Network Architecture (SNA) that enables...
Assembler
An Assembler is a program that translates `assembly language` source code into `machine code` (object code) executable by the CPU. In the z/OS environ...
ASID - Address Space Identifier
An ASID (Address Space Identifier) is a unique 16-bit identifier assigned by z/OS to each active address space within the system. It serves as a cruci...
ASM - Assembler
Assembler (ASM) is a low-level programming language that provides a symbolic representation of a computer's machine code. On IBM mainframes, it direct...
Asymmetric Multiprocessing
Asymmetric Multiprocessing (AMP) is a system architecture where different processors are assigned specific, specialized tasks and are not interchangea...
Attribute
In the context of IBM mainframe systems and z/OS, an **attribute** refers to a specific characteristic or property that defines an entity, such as a d...
Authorized Library
An Authorized Library in z/OS is a partitioned data set (PDS or PDSE) that contains programs permitted to execute with special system privileges, such...
Authorized Program
An Authorized Program in z/OS is a program that has been granted special privileges, allowing it to execute instructions that are typically restricted...
Automatic Restart Manager
The Automatic Restart Manager (ARM) is a z/OS component that automatically restarts failed batch jobs, started tasks (STCs), and TSO/E address spaces ...
Auxiliary Storage
Auxiliary storage, also known as secondary storage, refers to storage devices external to the mainframe's main memory (central storage or real storage...
Availability
Availability, in the mainframe context, is a critical measure of a system's uptime and its ability to provide continuous, uninterrupted service for bu...
ABCODE - Abend Code
An Abend Code, short for Abnormal End Code, is a hexadecimal or decimal value that indicates why a program or job terminated unexpectedly on an IBM ma...
ABTERM - Abnormal Termination
ABTERM, short for Abnormal Termination, refers to the unexpected and premature termination of a program, task, or job step on a mainframe system, typi...
Access Intent
In the context of mainframe database systems like DB2 for z/OS and IMS, **Access Intent** specifies how an application program intends to use data res...
ACID - Atomicity Consistency Isolation Durability
ACID is an acronym representing a set of properties (Atomicity, Consistency, Isolation, Durability) that guarantee reliable processing of database tra...
ACSID - Automatic Class Selection ID
In IBM z/OS, an ACSID (Automatic Class Selection ID) is a numeric identifier (0-255) assigned to a specific set of **Storage Management Subsystem (SMS...
Action Code - Processing instruction indicator
An action code is a single character or a short alphanumeric string entered by a user or program to instruct an application on a specific operation to...
Active Wait
In the context of z/OS, an active wait refers to a state where a CPU or a task is repeatedly checking for the availability of a resource or the comple...
ADABAS - Adaptable Database System
ADABAS (Adaptable Database System) is a high-performance, inverted list, non-relational database management system (DBMS) primarily used on IBM mainfr...
ADDRSPC - Address Space parameter
`ADDRSPC` is a JCL (Job Control Language) parameter used on the `JOB` or `EXEC` statement to specify the type of address space in which a job step or ...
ADMIN - Administrative authority level
In the z/OS environment, "ADMIN" refers to an elevated level of authority granted to users or processes, enabling them to perform critical system mana...
ADS - Application Development System
ADS (Application Development System) is a Fourth Generation Language (4GL) environment primarily associated with the CA IDMS database management syste...
Advanced Function - Enhanced capability
In the context of IBM mainframe systems and z/OS, an **Advanced Function - Enhanced capability** refers to a feature or set of features that extends t...
Affinity
In mainframe computing, particularly within a **sysplex** or distributed environment, **affinity** refers to a condition where a subsequent request, t...
After Image
In the context of mainframe database management systems (DBMS) like DB2 for z/OS and IMS DB, an After Image is a record of a data block, row, or segme...
Agent
An Agent, in the mainframe context, refers to a software component or program designed to perform specific tasks or collect information on behalf of a...
Aggregate
In the mainframe context, "aggregate" refers to the process of combining or summarizing detailed data into a higher-level, more concise form. This oft...
Alternate Index
An Alternate Index (AIX) is a VSAM component that provides an alternative access path to records in a VSAM Key-Sequenced Data Set (KSDS) or Entry-Sequ...
ALCINDEX - Alternate Index Cluster
An Alternate Index Cluster (ALCINDEX) in **VSAM (Virtual Storage Access Method)** is a secondary index that provides an alternative access path to rec...
Algorithm
In the context of mainframe computing, an **algorithm** is a finite, well-defined, step-by-step procedure or set of rules designed to solve a specific...
Allocate
In z/OS, `allocate` refers to the process of assigning a specific system resource, such as a dataset, storage space, or an I/O device, to a program, j...
ALTLIB - Alternate Library
`ALTLIB` (Alternate Library) is a TSO/E command that allows a user to dynamically and temporarily modify the search order for programs, CLISTs, and RE...
AMATERSE
AMATERSE is an IBM utility program for z/OS that provides data compression and decompression capabilities. It is primarily used to reduce the size of ...
Ambiguous
In the context of z/OS and mainframe programming, a condition where a statement, definition, or reference has more than one possible valid interpretat...
AMODE - Addressing Mode
AMODE (Addressing Mode) specifies the size of the memory addresses that a program or routine can generate and use to access virtual storage in an IBM ...
Anchor
In the mainframe context, an **anchor** refers to a fixed or known starting point, address, or reference that provides access to a larger data structu...
AND
The `AND` operator is a fundamental **logical conjunction operator** used in mainframe programming languages and scripting to combine two or more cond...
Annotation - Explanatory note
In the mainframe context, an annotation refers to an explanatory note or comment embedded within source code, JCL, scripts, or configuration files. It...
Anti-virus Software
Anti-virus software on z/OS is a specialized security application designed to detect, prevent, and remove malicious software (malware) such as viruses...
AOI - Application Owning Interface
The Application Owning Interface (AOI) is a CICS facility that allows CICS application programs (typically written in COBOL, PL/I, or Assembler) to is...
APAR - Authorized Program Analysis Report
An APAR (Authorized Program Analysis Report) is a formal report submitted by an IBM customer to IBM to document a suspected defect in an IBM licensed ...
APARs - Multiple APARs
An **APAR** (Authorized Program Analysis Report) is a formal report submitted to IBM by a customer detailing a suspected defect or problem in an IBM s...
APC - Asynchronous Procedure Call
An Asynchronous Procedure Call (APC) in the z/OS environment is a mechanism allowing a program or address space to request the execution of a routine ...
APL - A Programming Language
APL (A Programming Language) is a high-level, array-oriented, interpretive programming language known for its concise syntax and unique character set ...
APPLDATA - Application Data parameter
`APPLDATA` is a parameter used in various z/OS contexts, primarily within JCL `DD` statements or IDCAMS commands, to store user-defined, application-s...
Application ID
An `Application ID` (often abbreviated as `APPLID`) is a unique identifier assigned to an application or a specific instance of an application running...
APPLYCHECK
`APPLYCHECK` is an SMP/E (System Modification Program/Extended) command option that simulates the application of a software modification (SYSMOD), suc...
Archive
In the mainframe context, archiving refers to the process of moving infrequently accessed or historical data from primary online storage (like `DASD`)...
Archive Log
An `archive log` is a historical, sequential record of all committed changes made to a database (typically DB2 or IMS) on a z/OS system, generated whe...
ARITH
In the context of IBM mainframe systems and z/OS, an arithmetic operation refers to a fundamental computational process that involves numerical values...
ARM - Automatic Restart Management
Automatic Restart Management (ARM) is a z/OS component designed to enhance the high availability of critical applications and system services within a...
ARP - Address Resolution Protocol
Address Resolution Protocol (ARP) is a communication protocol used by the TCP/IP stack on z/OS to map an Internet Protocol (IP) address to a physical ...
Array
In the mainframe context, particularly within COBOL programming, an **array** (often referred to as a table) is an ordered collection of data elements...
ASA - American Standards Association
In the context of IBM mainframes and z/OS, ASA refers to the **American Standards Association (ASA) control characters** standard, a set of single-cha...
ASMH - High Level Assembler
High Level Assembler (ASMH) is the primary assembler program for IBM z/OS, responsible for translating assembler language source code into machine-exe...
Asynchronous
In the context of IBM mainframe systems and z/OS, **asynchronous** refers to operations or processes that do not block the calling program or task, al...
Attach
In the context of z/OS, "Attach" primarily refers to the system mechanism used to create a new task (often a subtask) that can run concurrently with t...
Attention - Interrupt signal
An Attention interrupt, often triggered by the `PA1` (Program Attention 1) key on a 3270 terminal, is a hardware-generated signal sent to the z/OS ope...
Attention Identifier (AID) Key
An Attention Identifier (AID) key is a special key on an IBM 3270 terminal (or its emulator) that, when pressed, signals an event or request to the ho...
Attribute Byte
In the context of IBM 3270 terminal emulation, an **attribute byte** is a special control character that precedes a field of display data, defining it...
Audit
In the mainframe context, an audit refers to the systematic and independent examination of system logs, security settings, application processes, and ...
Audit Trail
In the mainframe and z/OS environment, an **audit trail** is a chronological, tamper-resistant record of events, activities, or operations that have o...
Autoinstall
Autoinstall, primarily used within **CICS (Customer Information Control System)**, is a facility that dynamically creates resource definitions for ter...
Automatic Transaction Initiation (ATI) Feature
Automatic Transaction Initiation (ATI) is a core CICS (Customer Information Control System) feature that allows a transaction to be started automatica...
Autostart - Automatic startup
In the z/OS environment, "autostart" refers to the capability of the operating system or associated automation software to automatically initiate the ...
AUX - Auxiliary
In the context of z/OS, "Auxiliary" primarily refers to **auxiliary storage**, which is the paging space on Direct Access Storage Devices (DASD) used ...
AUXTR - Auxiliary Trace
AUXTR, or Auxiliary Trace, is a comprehensive system-wide tracing facility within z/OS that records significant system events, including program execu...
Availability Manager
An Availability Manager is a critical software component or system function within the z/OS environment designed to proactively monitor, manage, and r...
Available Frame
An **available frame** in z/OS refers to a unit of real storage (main memory) that is currently unused and unassigned to any virtual storage page. It ...
AWE - Address Windowing Extension
Address Windowing Extension (AWE) is a z/OS facility that enables 31-bit applications to access and manipulate data residing in 64-bit virtual storage...
AZYPARSE - Parse routine
AZYPARSE is an IBM-provided parse routine within z/OS that facilitates the standardized parsing and validation of input parameters for system utilitie...
B
Batch Processing
The execution of programs without manual intervention, typically scheduled to run during off-peak hours to process large volumes of data. Batch jobs a...
Big Iron
Colloquial term for mainframe computers, referring to their large physical size, robust construction, and reliable operation. The term emphasizes the ...
BSAM
A low-level access method for reading and writing sequential datasets that provides direct programmer control over I/O operations, buffering, and erro...
Binder
The z/OS link-editor program that processes object modules, control statements, and options to create executable load modules. The Binder combines sep...
Background Job
A background job in the z/OS environment refers to a program or series of programs executed non-interactively, without direct user intervention. It is...
Backup
A backup in the mainframe context is a copy of data (such as datasets, volumes, or database objects) created at a specific point in time, primarily fo...
Batch Job
A batch job on z/OS is a non-interactive program or series of programs executed sequentially without direct user intervention. It is typically submitt...
BCP - Basic Control Program
BCP, or Basic Control Program, is the core component of the z/OS operating system, responsible for managing system resources, executing programs, and ...
Binary
Binary is the base-2 number system, using only two symbols: 0 and 1. On IBM mainframes and z/OS, all data, including numeric values, character strings...
Bind
In z/OS, the **bind** process, often performed by the **Linkage Editor** or the **Program Management Binder (PMB)**, is the final step in creating an ...
BLDL - Build List
BLDL (Build List) is a z/OS Program Management SVC (Supervisor Call) that retrieves directory information for one or more members within a partitioned...
Block
In the context of IBM mainframe systems, a **block** (also known as a physical record) is a contiguous group of one or more logical records that are r...
Blocking Factor
The blocking factor is the number of logical records grouped together to form a single physical block of data on a storage device (like disk or tape)....
BPAM - Basic Partitioned Access Method
BPAM is an access method in z/OS specifically designed to manage and access data stored in **Partitioned Data Sets (PDS)** and **Partitioned Data Set ...
BSAM - Basic Sequential Access Method
BSAM (Basic Sequential Access Method) is a fundamental data access method in IBM z/OS that provides low-level control for reading and writing records ...
Buffer
A buffer is a temporary storage area in main memory (RAM) used to hold data during input/output (I/O) operations or data transfer between different co...
Bursting
In the context of IBM mainframe systems, **bursting** refers to the automated process of separating continuous-form printed output, typically fan-fold...
Byte
A byte is the fundamental unit of data in computing, consisting of 8 bits. In the mainframe and z/OS environment, it is the smallest addressable unit ...
Backout
In the mainframe context, **backout** refers to the process of reversing all uncommitted changes made by a transaction or program unit of work to rest...
Backward Recovery
Backward recovery, also known as rollback, is a data recovery technique used in mainframe systems to undo changes made to data, restoring it to an ear...
BAL - Branch and Link instruction
`BAL` (Branch and Link) is an IBM System/360 (and subsequent architectures like z/Architecture) assembly language instruction used to transfer control...
Balancing
In the mainframe and z/OS context, balancing refers to the strategic distribution of workloads across available system resources, such as CPUs, memory...
Band - Range or group
In the context of IBM z/OS and mainframe systems, a "band" conceptually refers to a defined, contiguous range or a logical grouping of resources, data...
Bandwidth
Bandwidth, in the context of IBM mainframe and z/OS, refers to the maximum rate at which data can be transmitted over a communication channel or netwo...
Base Register
In IBM mainframe z/OS environments, a **Base Register** is a General Purpose Register (GPR) used to establish addressability to a program's code and d...
Base Address
In the context of IBM mainframe architecture and z/OS, a **base address** is a starting memory location used in conjunction with a displacement (offse...
Base Priority
In z/OS, Base Priority refers to the initial dispatching priority assigned to a work unit (e.g., a task, SRB, or address space) by the Workload Manage...
Basic Mapping Support
Basic Mapping Support (BMS) is a CICS facility that simplifies the development of screen-oriented applications by separating the application logic fro...
Batch Window
A batch window is a predefined period, typically during off-peak hours, allocated for executing non-interactive batch jobs on an IBM z/OS mainframe. I...
BDAM - Basic Direct Access Method
BDAM (Basic Direct Access Method) is an IBM z/OS access method that allows programs to directly read and write records to a data set on a Direct Acces...
BDT - Bulk Data Transfer
BDT, or Bulk Data Transfer, is a z/OS component designed to facilitate the high-volume, high-speed transfer of data between z/OS systems, or between z...
Before Image
In the context of IBM mainframe database management systems like `DB2` and `IMS`, a `Before Image` is a copy of a data record, block, or page as it ex...
Bell
In the context of IBM mainframe systems, the **bell** refers to an audio alert signal generated by a 3270 terminal or its emulator. It serves as a non...
BG - Background region
In the context of IBM z/OS, a **Background region** (often abbreviated as BG) refers to an address space primarily dedicated to executing batch proces...
Bias - Adjustment factor
In the context of z/OS and JES2 (Job Entry Subsystem 2), a bias is a numerical weighting factor applied to a resource, such as an initiator or an outp...
Big Endian
Big Endian is a byte ordering method where the **most significant byte** (MSB) of a multi-byte data item is stored at the lowest memory address, and s...
Binary Search
Binary Search is an efficient algorithm used to locate a target value within a **sorted** list or array. In the mainframe context, it's frequently emp...
BIND - Database package creation
BIND is the process in IBM DB2 for z/OS that converts SQL statements embedded in an application program (like COBOL or PL/I) into an executable form, ...
Bind File
A bind file is an output generated by a database precompiler (most commonly the DB2 precompiler on z/OS) when processing an application program contai...
BINDCARD
A BINDCARD is a control card or input file used by the DB2 BIND command on z/OS to specify the parameters and options required to create or replace a ...
Bit - Binary digit
A bit (binary digit) is the smallest unit of data in a computer, representing one of two possible states, typically 0 or 1. In mainframe systems, bits...
Bit Map
A bit map is a data structure consisting of an array of bits, where each bit represents the status or state of a corresponding item or resource. In z/...
Blank - Space Character
The space character, often referred to as a "blank" on the mainframe, is a non-graphic character used primarily for delimiting fields, padding fixed-l...
BLKSIZE - Block Size
`BLKSIZE` (Block Size) is a data set attribute and JCL parameter that specifies the maximum physical block length, in bytes, for a data set. It define...
BMP - Batch Message Processing
A Batch Message Processing (BMP) program is a type of IBM Information Management System (IMS) application program that runs as a standard z/OS batch j...
Boolean
Boolean logic, in the mainframe context, refers to the fundamental concept of true/false evaluation used to control program flow, indicate status, and...
Bootstrap
In the mainframe context, "bootstrap" refers to the initial, self-starting process by which a computer system or a program loads itself into memory an...
Border
In the context of traditional mainframe 3270 terminal interfaces, a "border" refers to the character-based visual separation or framing used to deline...
Bottom - Lowest position
In the context of IBM mainframe systems, "bottom" refers to the lowest or final position within a sequential data stream, file, display screen, or log...
Boundary - Alignment restriction
In the context of IBM mainframe systems and z/OS, a...
Boundary Alignment
Boundary alignment in z/OS refers to the practice of positioning data items or instructions in storage at memory addresses that are exact multiples of...
BPI - Bytes Per Inch
Bytes Per Inch (BPI) is a measure of data density on magnetic tape, indicating the number of bytes stored linearly along one inch of the tape's length...
BPP - Bits Per Pixel
Bits Per Pixel (BPP) is a measure of the color depth of an image, indicating the number of bits used to represent the color of a single pixel. A highe...
Bpool - Buffer pool
A buffer pool (often abbreviated as Bpool) is a designated area of main memory (real storage) used by subsystems and applications on z/OS to temporari...
Bracket - Delimited Conversation
In the context of IBM Systems Network Architecture (SNA) and Advanced Program-to-Program Communication (APPC), a bracket is a logical construct that d...
Branch - Transfer of control
A branch instruction alters the sequential execution flow of a program by directing the CPU to fetch the next instruction from a different memory addr...
Branch Table
In mainframe computing, particularly in assembly language programming and compiler optimization, a **branch table** is a data structure, typically an ...
Breakpoint
A breakpoint in the z/OS environment is a designated point within a program's execution where the program is intentionally paused, allowing a debugger...
Broadcast
In the context of z/OS, "broadcast" primarily refers to the capability of sending messages or notifications to multiple users, terminals, or system co...
Browse
In the mainframe context, **Browse** refers to the act of examining the contents of a dataset, member, or system output without the ability to make an...
BSDS - Bootstrap Dataset
The Bootstrap Dataset (BSDS) is a critical VSAM Key-Sequenced Data Set (KSDS) that stores vital control information for an IBM Db2 for z/OS subsystem....
BTP - Business Transaction Processing
Business Transaction Processing (BTP) refers to the execution of discrete, self-contained units of work that represent a business event, such as a cus...
BTS - Business Transaction Services
BTS (Business Transaction Services) is a CICS facility that enables the definition, execution, and monitoring of long-running, multi-step business pro...
Bucket
In the context of mainframe data management, particularly within hashing-based access methods or database systems like IMS HDAM, a **bucket** refers t...
Build
In the mainframe context, "building" refers to the multi-step process of transforming source code (e.g., COBOL, PL/I, Assembler) into an executable pr...
Bulk Insert
Bulk insert refers to the highly efficient process of loading a large volume of data, comprising multiple rows, into a database table (e.g., DB2 for z...
Bundle
In the context of z/OS, a `bundle` is a deployable package that groups related resources or artifacts for a specific purpose, enabling their collectiv...
Burst Mode
In the context of IBM z/OS and mainframe I/O, Burst Mode refers to a high-speed data transfer mechanism where a device or channel sends a continuous s...
Bus
In the context of IBM mainframe systems and z/OS, a bus refers to a communication system that transfers data, addresses, and control signals between v...
Business Rule
A business rule is a statement that defines or constrains some aspect of a business, dictating how an organization operates, processes data, or makes ...
BYPASS
...
Byte Code
Byte code is an intermediate, platform-independent code generated by a compiler from source code, designed to be executed by a virtual machine rather ...
C
Cryptographic Hash
A cryptographic hash function takes an arbitrary-sized input (the "message") and produces a fixed-size string of bytes, known as a hash value, message...
CHP - Channel Path
A Channel Path (CHP) is a hardware component within an IBM mainframe's Channel Subsystem that provides a high-speed, dedicated data path between the C...
Chunk
In the mainframe context, a **chunk** refers to a discrete, contiguous block of data that is processed, transferred, or managed as a single unit. It r...
CICSPLEX
A CICSPLEX is a collection of one or more CICS regions that are managed as a single system image, allowing for centralized administration, workload ba...
CICS Region
A CICS region, also known as a CICS address space, is an independent operating system address space on IBM z/OS that hosts and executes CICS applicati...
CICSRPT
A CICS report, often generated from CICS monitoring data, provides detailed information about CICS region activity, transaction performance, resource ...
CICS Transaction
A CICS Transaction represents a complete, logical unit of work executed within a CICS (Customer Information Control System) region. It is typically in...
CID - Connection Identifier
In the context of IBM z/OS, a Connection Identifier (CID) is a unique alphanumeric name used primarily within CICS (Customer Information Control Syste...
CIDF - Control Interval Definition Field
The Control Interval Definition Field (CIDF) is a 4-byte field located at the end of a VSAM Control Interval (CI). Its primary purpose is to describe ...
CINET - CICS Internet
CINET, often referred to as CICS Internet, is a core component of CICS Transaction Server that enables CICS regions to act as both TCP/IP clients and ...
CINIT - Cross-Domain Initiation
CINIT (Cross-Domain Initiation) is a VTAM (Virtual Telecommunications Access Method) process where a logical unit (LU) in one VTAM domain requests to ...
CIR - Committed Information Rate
Committed Information Rate (CIR) is a Quality of Service (QoS) parameter in wide area networks (WANs) that specifies the guaranteed minimum bandwidth ...
Circuit - Communication path
In the mainframe context, a communication path refers to the logical or physical medium and associated protocols that enable data exchange between com...
Circular Wrapping
Circular wrapping, often implemented through a **circular buffer** or **circular queue**, is a data management technique where a fixed-size storage ar...
CISH - CICS Shared
CISH, or CICS Shared, refers to a mechanism within CICS (Customer Information Control System) that allows multiple CICS regions to share access to cer...
Claim - Requesting ownership
In the context of mainframe applications, "claiming ownership" of a record or resource typically refers to the act of acquiring an **exclusive lock** ...
Class Loading
Class loading is the process by which the Java Virtual Machine (JVM) locates, loads, links, and initializes Java classes into memory, making them avai...
Clause
An SQL clause is a distinct, keyword-driven component of an SQL statement that specifies a particular operation, condition, or characteristic. In the ...
CLAW - Common Link Access to Workstation
CLAW (Common Link Access to Workstation) is a programmatic interface on z/OS that enables workstation applications to communicate with mainframe appli...
Clean
In mainframe computing, "clean" primarily refers to a state of successful completion, proper resource management, or data integrity, indicating that a...
Cleanup
In mainframe computing, "cleanup" refers to the essential process of releasing system resources that were allocated to a program, job, or task upon it...
Clear
In mainframe computing, "clear" refers to the act of initializing a storage area, register, or control variable to a predefined default state, typical...
CLENGTH - Column Length
In the context of IBM mainframe systems, "Column Length" (often abbreviated as `CLENGTH` or `LENGTH`) refers to the defined maximum number of characte...
Command Line Interface
A Command Line Interface (CLI) in the z/OS context refers to a text-based user interface used to interact with the operating system and its utilities ...
Call Level Interface
In the context of mainframe databases like DB2 for z/OS, a Call Level Interface (CLI) is a standardized application programming interface (API) that a...
Client
In the mainframe context, a client is typically a program, application, or user that initiates a request for services or data from a mainframe-based s...
Clip - Limiting to range
"Clipping," in the context of data processing, refers to the operation of constraining a numerical or scalar value to fall within a specified minimum ...
CLOB - Character Large Object
A `CLOB` (Character Large Object) is a data type in IBM Db2 for z/OS used to store very large strings of character data, exceeding the typical limits ...
Clock - Timing mechanism
In z/OS, the system clock refers to the hardware and software mechanisms that provide accurate time-of-day (TOD) and interval timing services to the o...
Clone
In the mainframe context, a **clone** refers to an exact, independent duplicate of a resource, such as a dataset, a volume, a system image, a database...
Close
In the context of z/OS, `CLOSE` refers to the operation of releasing system resources associated with a data set, file, database connection, or other ...
Closed - Not accepting connections
In the context of mainframe networking and services, "Closed - Not accepting connections" describes the state of a network port or a service listener ...
Closeout - Final processing
In the context of IBM mainframe batch processing and application execution, "closeout" refers to the final set of operations performed at the end of a...
Closure
In the context of mainframe systems, **closure** primarily refers to the process of deallocating system resources associated with a data set or file a...
Cluster Controller
A Cluster Controller, historically exemplified by devices like the IBM 3274 or 3174, is a hardware device that manages and controls a group of IBM 327...
Clustering
In the mainframe and z/OS context, **clustering** refers to the practice of connecting multiple independent z/OS systems (LPARs or physical machines) ...
Clustering Index
A clustering index is a special type of index in DB2 for z/OS where the physical order of the data rows in the table space closely matches the logical...
CMA - Communications Management Application
CMA, or Communications Management Application, is a key component of the Network Control Program (NCP) that runs on an IBM Communication Controller (e...
CMD - Command
In the context of IBM z/OS, a command is an instruction issued to the operating system, a subsystem (like CICS, DB2, IMS), or a utility to perform a s...
CMDLANG - Command Language
CMDLANG, or Command Language, in the z/OS context, primarily refers to the embedded language used within application programs to interact with specifi...
CMDSTR - Command String
A `CMDSTR` (Command String) in z/OS refers to the literal text of an operator command, TSO command, or subsystem command (e.g., CICS, DB2, IMS) that i...
CMF - CICS Monitoring Facility
CMF, the CICS Monitoring Facility, is an integral component of IBM CICS Transaction Server for z/OS that collects detailed performance and resource ut...
CMRR - Couple Member and Recovery Routine
CMRR, or Couple Member and Recovery Routine, is a critical component within a z/OS sysplex responsible for managing the recovery of a specific Couplin...
CMPAT - Compatibility
In the IBM z/OS environment, `CMPAT` (Compatibility) is a parameter primarily used within `DFSMS` (Data Facility Storage Management Subsystem) constru...
CNOS - Change Number of Sessions
CNOS (Change Number of Sessions) is an APPC (Advanced Program-to-Program Communication) verb or function used to dynamically negotiate and modify the ...
CO - Central Office
The term "Central Office" (CO) primarily refers to a facility in telecommunications that houses equipment for connecting subscribers to the telephone ...
Coalesce - Combining fragments
In the mainframe context, coalescing refers to the process of combining adjacent, smaller free storage blocks or fragments into a single, larger conti...
COBOL Compiler
A COBOL compiler is a specialized software program that translates COBOL (Common Business-Oriented Language) source code, written by a programmer, int...
Code Page - Character encoding
A code page is a mapping table that defines how specific binary values (code points) correspond to human-readable characters. In the mainframe and z/O...
Code Point
A code point is a unique numeric value assigned to a specific character within a character set or encoding scheme, such as EBCDIC, ASCII, or Unicode. ...
Coded Character Set
A Coded Character Set (CCS) is a defined collection of characters (letters, numbers, symbols, control characters) where each character is assigned a u...
Coding Sheet - Programming form
A coding sheet, also known as a programming form, is a pre-printed paper form used by mainframe programmers in the past to hand-write source code (suc...
Coherency
In the context of IBM z/OS and mainframe systems, **coherency** primarily refers to **cache coherency**, ensuring that all processors in a multiproces...
Cold Start
A cold start refers to the process of initializing a mainframe subsystem (such as CICS, IMS, or DB2) from scratch, without utilizing any previous stat...
Collapse
In the context of IBM z/OS and mainframe systems, "collapse" refers to the process of **reducing the physical size or logical complexity of data**, ty...
Collating Sequence
In z/OS, a collating sequence defines the specific order in which characters are sorted or compared. It dictates the relative ranking of each characte...
Collection
In the context of IBM z/OS and enterprise computing, a **Collection** most commonly refers to a logical grouping of related entities. Its most promine...
Collection ID
A Collection ID in DB2 for z/OS is a logical name that identifies a group of DB2 packages. It serves as a qualifier for packages, allowing multiple ve...
Collision - Simultaneous access conflict
In the mainframe context, a collision refers to a simultaneous access conflict where multiple tasks, programs, or users attempt to access or modify th...
Colon - Delimiter character
A colon (:) is a special character used as a delimiter or separator in various mainframe contexts, including JCL, REXX, TSO/ISPF commands, and embedde...
Column
In the mainframe context, particularly within relational databases like DB2 for z/OS, a column represents a single, named attribute or field within a ...
Column Function - Aggregate Operation
An aggregate operation, often referred to as an aggregate function or column function in SQL, performs a calculation on a set of values in a column an...
Combiner - Merging multiple inputs
In the z/OS environment, a "combiner" refers to the function or process of merging multiple *already sorted* input data sets into a single, consolidat...
COMLIST - Communication List
A COMLIST (Communication List) is a fundamental mechanism in IBM mainframe programming, particularly in COBOL and Assembler, used to pass data (parame...
Command Area
In the mainframe context, a Command Area refers to a designated input field or buffer where users or programs enter commands for execution by the oper...
Command Level - CICS programming interface
Command Level is the standard application programming interface (API) for developing programs that run under CICS Transaction Server. It provides a hi...
Command Processor
A command processor in the z/OS environment is a specialized program designed to receive, parse, validate, and execute specific commands. It acts as a...
Commarea - Communication Area
A `Commarea` (Communication Area) is a contiguous block of memory used in CICS (Customer Information Control System) applications to pass data between...
Comment
In the mainframe environment, a **comment** is a non-executable line or block of text within source code, JCL, or other script files, intended solely ...
Commit
In the mainframe context, a **commit** operation finalizes a set of changes made to recoverable resources (such as databases or files) within a transa...
Commit Scope
Commit scope, often referred to as a **Unit of Work (UOW)**, defines the logical boundary of a transaction within which a set of related data modifica...
Common Queue Area
The Common Queue Area (CQA) is a critical component of z/OS virtual storage, residing within the Common Service Area (CSA) and Extended Common Service...
Commutation
While the term "Commutation" (meaning switching or substitution) is not a standard or commonly used technical term within the IBM mainframe z/OS ecosy...
Compaction
In the mainframe context, compaction refers to the process of reducing the physical size of data, typically to save storage space on DASD, reduce I/O ...
Comparand
A comparand, in the context of mainframe programming and operations, refers to a value, variable, or expression that is used as one of the operands in...
Compatibility
In the mainframe and z/OS context, **compatibility** refers to the ability of different hardware, software components, data formats, or system versio...
Compatibility Mode
In the mainframe context, Compatibility Mode refers to the ability of newer IBM mainframe hardware and z/OS operating system versions to execute appli...
Compensating Transaction
A compensating transaction is a subsequent, separate transaction designed to logically undo the effects of a previously committed transaction when a c...
Competitive - Requiring exclusive access
In the context of IBM mainframe systems, "competitive - requiring exclusive access" describes a resource that can only be safely used or modified by o...
Compilation
Compilation is the process of translating human-readable source code, written in a high-level programming language like COBOL, PL/I, or C/C++, into ma...
Compile Time
Compile time refers to the phase in the software development lifecycle where a program's source code is translated by a compiler into an executable fo...
Complement
In the context of mainframe computing, particularly for integer arithmetic, the **two's complement** is a mathematical operation used to represent sig...
Complete
In the context of IBM z/OS and mainframe operations, "complete" refers to the state where a process, such as a batch job, a started task, or a transac...
Component
In the mainframe and z/OS context, a component refers to a self-contained, modular, and often reusable part of a larger software system, application, ...
Composite
In mainframe computing, a **composite** entity refers to an item, structure, or identifier that is formed by combining two or more distinct, simpler c...
Composite Key
A composite key, also known as a multi-column key, is a primary or alternate key in a database table (or an index in a file) that consists of two or m...
Compound Condition
A Compound Condition in COBOL is formed by combining two or more simple conditions, or simple conditions and other compound conditions, using the logi...
Compression Exit
A Compression Exit is a user-written routine, typically developed in Assembler, COBOL, or PL/I, that is invoked by a z/OS system component, database m...
COMPX - Computational format
`COMPX` is a COBOL `USAGE` clause, typically an IBM extension, that specifies an **unsigned fixed-point binary** data item. It stores numeric values i...
COMTI - COM Transaction Integrator
COMTI (COM Transaction Integrator), now primarily known as Host Integration Server (HIS) Transaction Integrator (TI), is a Microsoft technology that e...
Concurrency
In the z/OS environment, concurrency refers to the ability of multiple independent tasks, programs, or users to execute or access shared resources see...
Concurrency Control
Concurrency Control in z/OS is a set of mechanisms and techniques used to manage simultaneous access to shared data and resources by multiple users, p...
Concurrent Copy
Concurrent Copy is a z/OS storage management feature that allows a consistent point-in-time copy of data to be created while applications continue to ...
Condition
In mainframe computing, a **condition** refers to a logical expression or a status that is evaluated to determine the subsequent flow of execution or ...
Condition Handler
In the context of z/OS, a condition handler is a specialized routine or block of code within a program designed to intercept, analyze, and respond to ...
Conditional
In the mainframe context, "conditional" refers to the execution of a specific action, statement, or block of code only if a predefined condition is me...
Conferencing - Multi-party communication
In the mainframe context, "Conferencing - Multi-party communication" refers to the coordinated exchange of information and actions among multiple z/OS...
Confidentiality
Confidentiality, in the mainframe context, refers to the principle of ensuring that sensitive data and resources are protected from unauthorized acces...
Configuration File
A configuration file in the z/OS environment is a dataset, a member within a partitioned dataset (PDS/PDSE), or a zFS file that contains parameters, s...
Confirmation - Acknowledgment of receipt
In the mainframe context, "Confirmation - Acknowledgment of receipt" refers to a mechanism where a receiving system, application, or process explicitl...
Conflict - Incompatible Requirements
In IBM z/OS and mainframe environments, a conflict due to incompatible requirements arises when two or more system components, applications, or config...
Conformance
In the mainframe and z/OS context, conformance refers to the degree to which a system, application, component, or process adheres to specified standar...
Connection
In the context of IBM mainframe systems and z/OS, a connection refers to an established, active communication pathway between two or more entities, su...
Connection Handle
In the mainframe context, a Connection Handle is an opaque identifier, typically an integer or pointer-like value, returned by a resource manager or m...
Connection Pooling
Connection pooling is a technique used in enterprise computing, including on z/OS, to manage and reuse a pool of established connections to backend re...
Connector
A software component or API that facilitates communication and data exchange between applications running on z/OS (e.g., CICS, IMS, DB2, batch) and ex...
Console Group
A Console Group in z/OS is a logical collection of operator consoles (both hardware and software-defined) that are configured to receive a specific su...
Constant
In the context of IBM mainframe systems, a constant is a fixed, unchangeable data value that is defined within a program, JCL, or script and remains u...
Constraint
In the context of IBM mainframe databases like DB2 for z/OS or IMS, a constraint is a rule or restriction defined on data to maintain its integrity an...
CICS Container
In CICS (Customer Information Control System), a container is a named, temporary data area used to pass data between CICS programs within a `channel`....
Contention
Contention in the mainframe context refers to the competition among multiple tasks, jobs, or users for access to a shared system resource. It occurs w...
Context
In z/OS, "context" refers to the specific environment, state, or set of conditions under which a program, transaction, or system component operates. I...
Context Switch
A context switch in z/OS is the process by which the operating system saves the current execution state (or "context") of a running program or task an...
Contingency Plan
A contingency plan in the mainframe context is a predefined, documented set of procedures and strategies designed to ensure the continued operation of...
Continuation
In the context of IBM mainframe systems, **continuation** refers to the mechanism by which a single logical statement or data element, such as a JCL s...
Continuity
In the mainframe context, continuity refers to the ability of critical business applications, data, and IT services to operate without interruption, ...
Continuous Operation - 24/7 Availability
In the mainframe context, **Continuous Operation - 24/7 Availability** refers to the capability of an IBM z/OS system and its associated applications ...
CA-7
A comprehensive job scheduling and workload automation tool from Broadcom (formerly Computer Associates) that manages batch processing workflows, depe...
Catalog
A system dataset that contains metadata about the location, characteristics, and attributes of other datasets on the mainframe system. The catalog pro...
CA - Computer Associates
CA Technologies, formerly Computer Associates, is a prominent independent software vendor (ISV) that provides a vast portfolio of mission-critical sof...
Cache
Cache refers to a high-speed storage component that stores frequently accessed data, instructions, or control information to reduce latency and improv...
Canceling
Canceling, in the z/OS context, refers to the premature termination of a running job, started task, or TSO user session before its normal completion. ...
CCW - Channel Command Word
A Channel Command Word (CCW) is an 8-byte instruction unit used by the mainframe's central processor to direct an I/O channel to perform a specific in...
Central Processor
The Central Processor (CP), often referred to as a General Purpose Processor (GPP) in the z/OS context, is the fundamental hardware component responsi...
Central Storage
Central Storage, also known as real storage or main memory, is the primary, high-speed, byte-addressable memory directly accessible by the CPU on an I...
Channel
A `channel` is a specialized processor within the IBM mainframe architecture that manages the flow of data between the central processing unit (CPU) a...
Channel Program
A Channel Program is a meticulously ordered sequence of Channel Command Words (CCWs) that defines and controls an I/O operation on an IBM mainframe. I...
Character Set
A character set is a defined collection of characters that a computer system can recognize and process, along with their corresponding numerical repre...
CICS - Customer Information Control System
CICS (Customer Information Control System) is a high-performance transaction manager and application server that runs on IBM z/OS mainframes. It provi...
CKD - Count Key Data
Count Key Data (CKD) is a fundamental data recording format used by IBM mainframe direct access storage devices (DASD). It defines how data is physica...
Class
In z/OS, a "Class" is a logical grouping mechanism used to categorize and manage various system resources, workloads, or entities. Its primary purpose...
CLIST - Command List
A Command List (CLIST) is a scripting language used on IBM z/OS systems, primarily within the TSO (Time Sharing Option) and ISPF (Interactive System P...
Cluster - VSAM dataset structure
In the context of IBM z/OS, a **VSAM cluster** is the fundamental storage object for Virtual Storage Access Method (VSAM) datasets. It represents the ...
CMS - Conversational Monitor System
CMS (Conversational Monitor System) is a single-user, interactive operating system component of IBM's VM (Virtual Machine) family of operating systems...
COBOL - Common Business Oriented Language
COBOL (Common Business Oriented Language) is a high-level programming language specifically designed for business, administrative, and financial appli...
Command
A command in the z/OS environment is an instruction issued to the operating system, a subsystem (like CICS or DB2), or an application to perform a spe...
Common Area
In the context of IBM z/OS, a Common Area refers to a portion of virtual storage that is accessible and shared by multiple address spaces or programs....
Common Service Area
The Common Service Area (CSA) is a critical region of virtual storage within a z/OS address space that contains control blocks and data structures acc...
Communication Server
IBM z/OS Communication Server is the integrated, high-performance networking component of the z/OS operating system. It provides comprehensive support...
Compiler
A compiler is a specialized program that translates source code written in a high-level programming language (such as COBOL, PL/I, C/C++, or Java) int...
Compression
Compression, in the mainframe context, refers to the process of reducing the physical size of data to optimize storage space on direct access storage ...
Concatenation
In z/OS, concatenation refers to the process of logically linking multiple sequential datasets or partitioned dataset (PDS/PDSE) members together to f...
Concurrent
In the context of IBM z/OS, **concurrent** refers to the ability of the operating system to manage and execute multiple tasks, programs, or processes ...
Condition Code
A Condition Code (CC) is a numeric status indicator set by the CPU, an operating system service, or an application program to reflect the outcome of a...
Configuration
Configuration in the mainframe context refers to the comprehensive process and resulting state of defining, customizing, and setting parameters for ha...
Console
A console, in the mainframe context, is the primary operator interface terminal used to monitor, control, and interact with the z/OS operating system,...
Control Block
A control block is a structured area of main storage (RAM) used by the z/OS operating system and its components to store critical information about sy...
Control Card
In the context of JCL and z/OS, a control card is a data record or set of records passed as input to a utility program or application program, contain...
Control Program
The Control Program is the core component of an operating system responsible for managing system resources, scheduling tasks, handling input/output (I...
CICS Control Region
The CICS Control Region is a dedicated z/OS address space where the CICS Transaction Server executes. It serves as the primary operational environment...
Control Section
In IBM mainframe assembly language and compiled languages like COBOL or PL/I, a Control Section (CSECT) is a relocatable unit of code or data that the...
Conversational Mode
In the mainframe context, **Conversational Mode** refers to an interactive processing technique where a program maintains its state and resources (lik...
COPYLEFT
Copyleft is a software licensing approach that grants users the freedom to run, study, modify, and distribute software and its modified versions, with...
Core Dump
A core dump, in the z/OS context, is a snapshot of a program's or system's memory and register contents taken at the time of an abnormal termination (...
Coupling Facility
A specialized hardware component that provides high-speed shared memory and processing capabilities for multiple z/OS systems within an **IBM Parallel...
CP - Control Program
In the context of IBM mainframe operating systems like z/OS, the `Control...
CPU - Central Processing Unit
The Central Processing Unit (CPU) on an IBM mainframe is the core hardware component responsible for executing program instructions, performing calcul...
Cross-Memory
Cross-memory is a z/OS facility that allows a program executing in one address space to directly access data located in another address space. It prov...
CSECT - Control Section
A Control Section (CSECT) is a relocatable unit of code or data within an assembly language program or a high-level language (HLL) compilation unit on...
CSR - Console Status Report
The Console Status Report (CSR) refers to the real-time information displayed on the z/OS system console in response to various operator `DISPLAY` com...
CVT - Communication Vector Table
The Communication Vector Table (CVT) is a fundamental, system-wide control block in z/OS that acts as a central repository of pointers to other critic...
Cylinder
A cylinder is a fundamental unit of disk storage organization on mainframe Direct Access Storage Devices (DASD), representing all tracks at the same r...
Cache Coherency
Cache coherency in the mainframe context refers to the mechanism that ensures consistency of data stored in multiple local caches across different pro...
Cache Hit
A cache hit occurs when a processor, storage controller, or software subsystem successfully retrieves requested data from its high-speed cache memory ...
Cache Line
A cache line is the smallest unit of data that can be transferred between a processor's cache memory (L1, L2, L3) and main memory (central storage) on...
Cache Miss
A `cache miss` occurs when a processor, storage controller, or software component attempts to access data, but that data is not found in its designate...
Caching
Caching in the mainframe context refers to the process of storing frequently accessed data or instructions in a faster, smaller memory component close...
CAE - Common Application Environment
A Common Application Environment (CAE) in the z/OS context refers to a standardized and integrated set of software components, tools, and architectura...
CAF - Call Attach Facility
The Call Attach Facility (CAF) is an IBM DB2 for z/OS application programming interface (API) that allows z/OS applications, typically batch programs ...
CAI - Computer Aided Instruction
Computer Aided Instruction (CAI) on the mainframe refers to interactive, self-paced educational programs delivered via mainframe terminals, designed t...
Calendar - Date scheduling system
In the mainframe context, a Calendar refers to a critical component within a workload automation or job scheduling system (e.g., IBM Z Workload Schedu...
Call
...
Call Level Interface (CLI) Programming Method
The Call Level Interface (CLI) is a standard programming interface that allows applications to access and manipulate data in a relational database (su...
Callable
In the mainframe context, a "callable" entity refers to a self-contained unit of code (such as a program, subroutine, or function) designed to be invo...
Callback
In the mainframe context, a **callback** refers to a function or routine that is passed as an argument to another program or system service, to be inv...
Calling Convention
In the z/OS environment, a **calling convention** defines the standardized rules and mechanisms by which one program (the caller) invokes another prog...
Calling Program
A calling program, in the mainframe context, is an executable program (e.g., a COBOL program, Assembler module, or PL/I program) that initiates the ex...
CAM - Channel Attention Module
The Channel Attention Module (CAM) is a fundamental hardware mechanism within IBM mainframe systems, primarily used by a channel to signal a control u...
CAP - Change Accumulation Program
A Change Accumulation Program (CAP) is an IBM IMS utility that processes IMS log records (OLDS/SLDS) to consolidate database changes that have occurre...
Capacity
In the mainframe context, **capacity** refers to the maximum capability of a system or its components (e.g., CPU, memory, I/O, storage, network) to pr...
Captive - Restricted environment
In the mainframe context, a **captive environment** refers to a highly controlled and isolated computing space designed to restrict user access, progr...
Cardinality
In the context of IBM mainframe databases like **DB2 for z/OS** or **IMS**, cardinality refers to the number of rows (or segments/occurrences for IMS)...
Carriage Control - Print positioning
In IBM mainframe systems, carriage control refers to special characters or bytes embedded as the first character of a print record that instruct the p...
Carrier
In the context of data transmission, a **carrier** refers to an analog signal (typically a sine wave) that is modulated to carry digital information o...
Cartridge
In the mainframe context, a **cartridge** refers to a self-contained, removable unit that houses a reel of magnetic tape, primarily used for storing l...
CASCADE
In the mainframe context, particularly within database management systems like DB2 or security systems like RACF, a **cascade** operation refers to an...
Case Sensitive
In the context of mainframe systems, **case sensitivity** refers to whether a system, program, or component distinguishes between uppercase and lowerc...
CASS - Common Assembly System
CASS (Common Assembly System) is a critical component of the **IBM High Level Assembler (HLASM)** for z/OS, providing a collection of common services,...
CAT - Catalog
A catalog (specifically a **VSAM Catalog** or **z/OS Catalog**) is a crucial system component within z/OS that records the location and attributes of ...
Catalog Recovery
In z/OS, Catalog Recovery refers to the process of restoring an `Integrated Catalog Facility (ICF)` catalog to a consistent and usable state after it ...
Catalog Search
In z/OS, a catalog search is the fundamental process by which the operating system locates a dataset's physical attributes and storage location (volum...
CBT - Chicago Board of Trade tape
The CBT tape is a widely recognized, historical, and continuously updated collection of public domain software, utilities, and tools for IBM mainframe...
CBTTAPE - CBT utilities collection
CBTTAPE refers to a widely recognized collection of user-contributed utilities, tools, and source code specifically designed for IBM mainframe z/OS en...
CCCA - Channel to Channel Adapter
A Channel to Channel Adapter (CCCA) is a specialized hardware component on IBM mainframe systems that provides a high-speed, direct connection between...
CCP - Communication Control Program
The Communication Control Program (CCP) is a fundamental internal component of IBM's CICS (Customer Information Control System) that is responsible fo...
CCS - Coded Character Set
A Coded Character Set (CCS) is a defined collection of characters (letters, numbers, symbols, control characters) where each character is assigned a u...
CCSID - Coded Character Set Identifier
A Coded Character Set Identifier (CCSID) is a 16-bit number that uniquely identifies a specific character encoding scheme used to represent textual da...
CD
In the context of IBM z/OS, `CD` (Change Directory) is a fundamental command used within the Unix System Services (USS) environment to alter the curre...
CDSA - Common Data Security Architecture
The Common Data Security Architecture (CDSA) is a modular, extensible framework that provides a standardized application programming interface (API) f...
Cell
In the context of mainframe programming, particularly COBOL, a **cell** refers to an individual data element or storage location within a larger struc...
Cell Pool
A `cell pool` is a specialized storage management mechanism in z/OS that pre-allocates and manages a collection of fixed-size storage blocks, known as...
Centralized
In the context of IBM mainframe systems and z/OS, "centralized" refers to an architecture where computing resources, data storage, and processing logi...
Certificate
A digital certificate is an electronic document that uses public-key cryptography to verify the identity of an individual, organization, or server. In...
CESD - Composite External Symbol Dictionary
The Composite External Symbol Dictionary (CESD) is a crucial section within an IBM z/OS load module or program object. It contains a comprehensive lis...
CEX - Crypto Express
Crypto Express (CEX) refers to a family of specialized hardware adapters on IBM zSystems mainframes designed to provide high-performance, secure crypt...
CFL - Compression Function Library
CFL, or Compression Function Library, is a set of IBM-provided routines on z/OS designed to efficiently compress and decompress data. It leverages spe...
CGI - Common Gateway Interface
CGI (Common Gateway Interface) is a standard protocol that defines how an information server, such as a web server running on z/OS, communicates with ...
Chain - Linked Sequence
In the mainframe context, a "chain" refers to a sequence of logically connected elements, typically control blocks, data buffers, or I/O commands, whe...
Chained List
A chained list, also known as a linked list, is a fundamental data structure where elements are stored non-contiguously in memory. Each element, or no...
Change Management
Change Management, in the mainframe context, refers to the structured process of controlling, tracking, and auditing modifications made to system soft...
Changed - Modified indicator
A `changed - modified indicator` is a flag or status bit associated with a data item, record, or screen field that signals whether its value has been ...
Character String
A character string, in the mainframe context, is a contiguous sequence of bytes representing textual data, where each byte (or sequence of bytes) corr...
Checkpoint
In the context of IBM mainframe systems, a **checkpoint** is a mechanism used to capture and save the current state of a running program, transaction,...
Checkpoint/Restart
Checkpoint/Restart is a vital recovery mechanism in z/OS that enables long-running batch jobs or online transactions to resume execution from an inter...
Child
In mainframe computing, a "child" or "subordinate element" refers to an entity that is dependent on, contained within, or directly related to a higher...
CICSPLEX - CICS complex
A CICSplex is a collection of CICS regions that operate as a single logical entity, providing a unified view of CICS resources and applications. Its p...
CICSRPT - CICS Report
A CICS Report, often referred to as CICSRPT, is a structured output generated from CICS (Customer Information Control System) monitoring and accountin...
Circular - Wrapping Around
This concept describes a data structure or resource management technique where, upon reaching the end of an allocated space, operations continue from ...
CLAIM
In the context of mainframe and z/OS, a "claim" refers to the act of asserting control or requesting exclusive access over a shared system resource, s...
Cleanup - Releasing resources
In mainframe computing, "cleanup" refers to the systematic process of releasing system resources (such as memory, files, datasets, locks, and devices)...
CLI
CLI is an acronym with two distinct yet important meanings within the mainframe and z/OS ecosystem. As **Command Line Interface**, it refers to a text...
Command String
In the context of CICS (Customer Information Control System), a Command String (CMDSTR) refers to a character string containing a C...
Coalesce
In the context of z/OS, "coalesce" refers to the process of combining smaller, non-contiguous fragments of free space or dataset extents into larger, ...
Code Page
A code page is a table that maps character codes (binary values) to specific characters (letters, numbers, symbols). In the mainframe and z/OS context...
Collision
In the context of IBM z/OS and mainframe computing, a collision refers to a simultaneous access conflict where multiple tasks, programs, or systems at...
Combiner
In the mainframe context, a "Combiner" refers to a utility function or process designed to consolidate multiple input datasets or data streams into a ...
Compaction - Data Compression
In the mainframe context, data compaction (often synonymous with data compression) refers to the process of reducing the physical size of data stored ...
COMPX
`COMPX` (or `COMPUTATIONAL-X`) is a COBOL `USAGE` clause that specifies a binary representation for numeric data items. In IBM COBOL for z/OS, `COMPX`...
Concurrency - Simultaneous execution
Concurrency in the mainframe z/OS environment refers to the operating system's and applications' ability to manage and execute multiple independent ta...
Conferencing
In the mainframe context, "conferencing" refers to systems or applications designed to facilitate multi-party communication and collaboration among us...
Console Group - Related operator consoles
A console group in z/OS is a logical collection of operator consoles, defined to facilitate message routing, command processing, and operator workload...
Continuation - Extending beyond
In mainframe computing, "continuation" refers to the practice and syntax rules that allow a single logical statement, parameter, or literal to...
Continuous Operation
In the mainframe context, **Continuous Operation** refers to the ability of a system or application to remain available and process workloads without ...
Contour
In a general computing context, a contour refers to the **boundary** or **outline** that defines the extent, shape, or limits of a particular entity, ...
Control Area
A Control Area (CA) is a fixed-size unit of physical storage space within a VSAM (Virtual Storage Access Method) dataset on z/OS. It is the largest un...
Control Flow
Control flow, often referred to as execution sequence, defines the order in which instructions, statements, or job steps are executed within a program...
Control Interval
A Control Interval (CI) is a fixed-length block of data that VSAM (Virtual Storage Access Method) uses as its fundamental unit for physical input/outp...
Control Point - Synchronization point
In the context of IBM z/OS and enterprise transaction processing, particularly within CICS, a **control point** or **synchronization point** (`syncpoi...
Control Table - System data structure
In mainframe systems, particularly z/OS and its subsystems (CICS, IMS, DB2), a control table is a structured collection of data used by programs or sy...
Control Unit - Device controller
In the IBM mainframe environment, a Control Unit (often referred to as a Device Controller) is a hardware component that acts as an intermediary betwe...
Controlled
In the z/OS environment, "controlled" refers to the systematic application of rules, policies, and mechanisms to manage, restrict, and govern access t...
Conversation
In the context of IBM mainframe transaction processing systems like CICS and IMS, a conversation refers to a series of logically related interactions ...
Conversion
...
Cooperative - Sharing Resources
In the z/OS environment, "cooperative - sharing resources" refers to the fundamental architectural principle and the various mechanisms that enable mu...
Coordinate
In the context of z/OS and enterprise computing, "coordinate" primarily refers to the process of ensuring atomicity and consistency across multiple in...
Coordinator
In the context of z/OS, a **coordinator** is a component, typically within a transaction manager like CICS or IMS, responsible for managing the integr...
Coprocessor - Auxiliary processor
In the mainframe context, a coprocessor or auxiliary processor is a specialized hardware component designed to perform specific, computationally inten...
Copy - Duplicate
In the mainframe context, "copy" refers to the process of creating an identical or near-identical replica of data, a program, a library member, or an ...
Copy Book
A copy book is a file containing reusable source code segments, typically used to define common data structures, record layouts, or procedural code. I...
Copy Pool
A Copy Pool is a logical grouping of storage volumes within an IBM DS8000 series storage system, specifically designated to serve as target volumes fo...
Core
In the context of IBM mainframes and z/OS, "Core" historically refers to **main storage** (also known as real storage or central storage). It is the p...
Coroutine - Cooperative Subroutine
A coroutine, in its general computing sense, is a program component that generalizes subroutines, allowing multiple entry points for suspending and re...
Corrective Service
A corrective service, often referred to as a fix or patch, is a software update provided by IBM or other vendors to address specific defects, security...
Correlation
In the context of IBM mainframe systems and z/OS, correlation refers to the process of linking related events, transactions, or data points across dif...
Correlator
A correlator is a unique identifier used in mainframe systems, particularly z/OS, to link related events, messages, or transactions across different c...
Corrupt
In the mainframe context, **corrupt** refers to data, a file, a dataset, a program, or a system component that has become damaged, inconsistent, or in...
COS - Class of Service
Class of Service (COS) is a network management mechanism used in IBM's Systems Network Architecture (SNA) and extended to IP networks on z/OS to defin...
Cost
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Cost Estimate - Predicted Resource Usage
A cost estimate in the mainframe context refers to the prediction of resource consumption (e.g., CPU cycles, I/O operations, memory, storage) required...
Count
In the context of IBM mainframe systems, "count" primarily refers to the number of times a specific data item, record, or event is repeated or observe...
Counter
In mainframe programming, particularly with languages like COBOL and PL/I, a counter is a numeric variable used to keep track of the number of occurre...
Coupled
In the z/OS environment, "coupled" primarily refers to the state where multiple z/OS systems are logically connected and operate together as a single ...
Coupling Dataset
A Coupling Dataset (CPLXDS) is a specialized dataset residing on a DASD device that serves as a repository for control information and definitions for...
Coupling Services
Coupling Services, primarily facilitated by the **Coupling Facility (CF)**, provide high-speed, shared memory and specialized hardware functions that ...
Coverage
In the mainframe context, **test coverage** refers to the degree to which the source code of a program (e.g., COBOL, PL/I, Assembler) or a system's fu...
CPA - Common Programming Interface
While the standard IBM mainframe acronym for this concept is **CPI** (Common Programming Interface), this term refers to a set of standardized applica...
CPDUMP - Coupling Facility Dump
A CPDUMP (Coupling Facility Dump) is a specialized diagnostic tool in IBM z/OS used to capture the contents of a specific Coupling Facility (CF) struc...
CPID - Communication Process ID
In the context of IBM z/OS and SNA (Systems Network Architecture), a CPID (Communication Process ID) is an internal identifier used by **VTAM (Virtual...
CPP - CICS Problem Program
A CICS Problem Program (CPP) is an application program, typically written in COBOL, PL/I, or Assembler, designed to execute within an IBM CICS (Custom...
CPSMF - Common Platform SMF
CPSMF, or Common Platform SMF, refers to a solution or framework designed to collect, consolidate, and stream System Management Facilities (SMF) data ...
CPU Bound
A workload or program is considered CPU bound when its performance is primarily limited by the speed and availability of the central processing unit (...
CQS - Common Queue Server
CQS (Common Queue Server) is a z/OS component that provides high-performance, high-availability shared queue services for multiple client address spac...
CR - Carriage Return
Carriage Return (`CR`) is a control character, primarily defined in ASCII as `X'0D'`, that historically signaled a print head or cursor to return to t...
Crash
A crash, in the mainframe context, refers to the unexpected and uncontrolled termination of a z/OS operating system, a specific subsystem (like CICS o...
CRC - Cyclic Redundancy Check
CRC (Cyclic Redundancy Check) is an error-detecting code used in digital networks and storage devices to detect accidental changes to raw data. In the...
Create
In the context of IBM z/OS and mainframe systems, "create" refers to the process of allocating, defining, or instantiating a new resource, object, or ...
Credentials
In the mainframe context, credentials refer to the authentication information required by a user, program, or system component to verify its identity ...
Critical
In the mainframe context, "critical" refers to a state, resource, task, or problem that is essential for the continued operation, integrity, or availa...
Critical Section
A critical section in z/OS refers to a segment of code that accesses shared resources (e.g., data structures, files, memory areas) and must be execute...
Cross Check
A cross-check, in the mainframe context, refers to a verification process where data or calculated results from one source or method are compared agai...
Cross Invalidate
In a z/OS sysplex, cross invalidate refers to the process where one system notifies other systems that a cached copy of a shared data block has become...
Cross Memory Mode
Cross Memory Mode is a z/OS facility that enables a program executing in one address space to directly access data or execute code residing in another...
Cross Partition - Spanning LPARs
In the context of IBM mainframes, "cross-partition" or "spanning LPARs" refers to processes, resources, or communication mechanisms that operate, inte...
Cross Reference
A cross reference, in the context of IBM mainframe systems and z/OS, is a listing or mechanism that identifies where specific program elements (such a...
Cross System
In the context of IBM mainframes and z/OS, "cross system" refers to operations, data sharing, or resource management that spans multiple independent z...
CRP - Channel Reconfiguration Program
CRP, or Channel Reconfiguration Program, is a z/OS component that enables **dynamic reconfiguration of the I/O configuration** without requiring an IP...
CRT - Cathode Ray Tube
A Cathode Ray Tube (CRT) is an obsolete vacuum tube technology that produced images by firing an electron beam onto a phosphorescent screen. In the ma...
Cryptography
Cryptography on z/OS refers to the practice and study of secure communication techniques, primarily involving the use of mathematical algorithms and s...
CSASIZ - CSA Size parameter
`CSASIZ` is a parameter specified in the `IEASYSxx` member of `SYS1.PARMLIB` that defines the initial size of the **Common Service Area (CSA)** and **...
CSD - CICS System Definition
The CICS System Definition (CSD) is a VSAM Key-Sequenced Data Set (KSDS) that serves as the central repository for all CICS resource definitions. It s...
CSECT Name - Control Section Name
A Control Section (CSECT) is a relocatable unit of code or data within an object module, defining an independent, addressable block that can be proces...
CSMF - CICS System Management Facility
CSMF (CICS System Management Facility) is a CICS component that provides a standardized, programmatic interface for external system management product...
CSMT - CICS Master Terminal Transaction
`CSMT` (CICS Master Terminal) is a powerful, privileged CICS transaction used by system programmers and operators to **monitor and control the CICS re...
CT - Control Table
A Control Table (CT) in the mainframe context is a structured data area, typically residing in memory, used by programs, subsystems, or the operating ...
CTCA - Channel to Channel Adapter
A Channel to Channel Adapter (CTCA) is a hardware device or a logical construct that enables high-speed, direct communication between two IBM mainfram...
CTC Ring
A CTC Ring, or Channel-to-Channel Ring, is a specialized hardware and software configuration used in IBM mainframe environments to facilitate high-spe...
CTHREAD - CICS Thread
A CICS Thread is a dedicated connection or pathway established between a CICS region and an external resource manager, most commonly a **DB2 subsystem...
CTL - Control
In the mainframe context, "Control" (often abbreviated as `CTL`) refers to **control statements** or **control cards** that provide specific instructi...
CTR - Counter
A counter, in the context of IBM mainframe systems and z/OS, is a numeric variable or register used to track the number of occurrences of an event, it...
CUA - Common User Access
Common User Access (CUA) is a set of IBM guidelines for designing consistent user interfaces, primarily for character-based terminals like the 3270, p...
CUE - Communication User Exit
A Communication User Exit (CUE) is a user-written program or routine that allows system programmers to intercept and customize the behavior of communi...
Cumulative
In the context of z/OS and mainframe systems, "cumulative" refers to a metric or value that continuously accumulates or sums up over a defined period,...
Currency
In the context of mainframe databases and file systems, **currency** refers to the current logical position within a dataset, database segment, or rec...
Current
In the z/OS environment, "current" refers to the active, most recent, or presently executing state of a resource, process, or data element. It signifi...
Current Row - Active database row
In the context of mainframe database access (e.g., DB2, IMS), the **current row** refers to the specific database record or segment that a program is ...
Cursor
In the mainframe context, a **cursor** primarily refers to the visual position indicator on a 3270 terminal screen (or emulator) that shows where the ...
Cursor Stability (CS) - Isolation Level
Cursor Stability (CS) is an isolation level in database management systems like DB2 for z/OS that ensures any row read by a transaction will not be ch...
Custom
In the mainframe context, "custom" refers to software, configurations, or procedures that are specifically developed or modified to meet unique busine...
Customization
Customization in the z/OS environment refers to the process of modifying standard IBM or third-party vendor software to meet the unique operational re...
Cutover
In the context of IBM mainframe systems and z/OS, a cutover is the critical final phase of a project where a new or upgraded system, application, or i...
CVD - Convert to Decimal
`CVD` (Convert to Decimal) is an IBM mainframe machine instruction that converts a 64-bit signed binary integer from a general-purpose register (GPR) ...
Cycle
In the context of IBM mainframe systems, a "cycle" refers to a recurring, scheduled sequence of batch jobs, system processes, or data processing tasks...
Cycle Stealing - Priority interrupt
**Cycle Stealing** is a hardware mechanism, primarily associated with mainframe I/O channels, that allows peripheral devices or their controllers to d...
Cyclic
In the context of z/OS, "cyclic" primarily refers to a pattern of data set usage where a predefined set of data sets is reused sequentially in a repea...
CYL - Cylinder
A **cylinder** (CYL) on an IBM mainframe Direct Access Storage Device (DASD) refers to the set of all tracks that are equidistant from the center of t...
D
Data Alignment
Data alignment refers to the requirement that certain data items in memory or storage must begin at a memory address that is a multiple of their size ...
D2D - Disk to Disk
In the context of IBM mainframe systems and z/OS, D2D (Disk to Disk) refers to the process of transferring data directly from one disk storage device ...
DAE - Dump Analysis and Elimination
DAE (Dump Analysis and Elimination) is a z/OS component designed to automatically analyze and suppress duplicate or non-critical system dumps (SVC dum...
DAOS - Distributed Application Operating System
DAOS (Distributed Application Operating System) refers to a conceptual or architectural framework, often implemented through a combination of middlewa...
Dark Fiber
Dark Fiber, in the context of mainframe systems, refers to installed fiber optic cable infrastructure that is not currently "lit" or actively transmit...
DASD Cache
DASD Cache, or disk cache memory, is a high-speed memory component integrated within a Direct Access Storage Device (DASD) controller or storage subsy...
DASDM - DASD Management
DASD Management (Direct Access Storage Device Management) refers to the comprehensive set of processes, tools, and policies used to administer, optimi...
Data Capture
...
Data Compression
Data compression on z/OS is the process of reducing the physical size of data by encoding it more efficiently, primarily to optimize storage utilizati...
Data Currency
Data currency refers to the degree to which data is up-to-date and accurately reflects the current state of the real-world entities it represents. In ...
Data Description - Metadata
In the mainframe context, metadata, often referred to as data description, is data about data. It describes the characteristics, structure, format, an...
Data Dictionary
A Data Dictionary is a centralized repository that stores metadata, which is "data about data." In the mainframe context, it serves as a comprehensive...
Data Encryption
Data encryption on z/OS involves transforming sensitive data into an unreadable format (ciphertext) using an algorithm and a cryptographic key, preven...
Data Entry
In the mainframe context, **Data Entry** refers to the process of inputting raw data into a computer system, typically via a terminal or through batch...
Data Exception
A Data Exception (often resulting in an S0C7 abend) is a type of program check that occurs on IBM z/OS systems when a program attempts to perform an o...
Data Extraction
Data Extraction on z/OS involves retrieving specific subsets of data from various mainframe data sources, such as VSAM files, DB2 tables, IMS database...
Data Hiding and Encapsulation
In the mainframe context, data hiding and encapsulation refer to the principle of structuring programs and systems such that the internal implementati...
Data Independence
Data independence is the ability to modify the schema or physical organization of data without requiring changes to the application programs that acce...
Data Integrity
In the mainframe and z/OS environment, **Data Integrity** refers to the accuracy, consistency, and reliability of data throughout its lifecycle. It en...
Data Interchange
Data Interchange on IBM z/OS refers to the structured exchange of information between different applications, systems, or organizations, typically inv...
Data Model
A data model is an abstract representation that defines the structure, organization, relationships, and constraints of data within an information syst...
Data Object
In the mainframe context, a **data object** refers to a discrete, identifiable unit of information that is stored, processed, or manipulated by progra...
Data Origin
In the mainframe context, **Data Origin** refers to the specific system, application, process, or external source from which a particular set of data ...
Data Propagation
Data propagation in the mainframe context refers to the process of copying, moving, or synchronizing data from one source to one or more target locati...
Data Provider
In the mainframe context, a Data Provider is a component, service, or system that makes specific data available to other applications, services, or ex...
Data Rate
In the mainframe context, **Data Rate** refers to the speed at which data is transferred between components, such as between a CPU and storage devices...
Data Replication
Data replication in the z/OS environment is the process of creating and maintaining consistent copies of data across different storage systems, Logica...
Data Security
Data security in the mainframe context refers to the comprehensive measures and controls implemented within IBM z/OS environments to protect informati...
Data Segment
A `data segment` in the context of z/OS primarily refers to a distinct section within a program's virtual storage address space or `load module` that ...
Data Sensitivity - Importance Level
Data sensitivity, in the context of IBM z/OS, refers to the classification of data based on its confidentiality, integrity, and availability requireme...
Data Set Attributes
Data set attributes are metadata properties that describe the characteristics and organization of a data set on an IBM z/OS system. They define how da...
Data Sharing - Concurrent Access
In the z/OS environment, data sharing with concurrent access refers to the capability for multiple independent applications, address spaces, or even d...
Data Stream
In the mainframe context, a **data stream** refers to a continuous, sequential flow of data, typically bytes or characters, between two points. These ...
Data Structure
In the mainframe context, a **data structure** defines the organization and format of data elements, typically within a record, file, or memory area, ...
Data Type
In the mainframe and z/OS context, a data type defines the kind of data a variable or field can hold, such as numeric, alphanumeric, or packed decimal...
Data Validation
Data validation is the process of ensuring that data entered into or processed by an IBM mainframe system is accurate, complete, consistent, and adher...
Data Warehouse
A Data Warehouse is a centralized repository of integrated, historical, and subject-oriented data, primarily used for reporting and analytical purpose...
Database Administrator
A Database Administrator (DBA) on IBM mainframe systems is a highly specialized technical professional responsible for the design, implementation, mai...
Database Buffer Pool
A Database Buffer Pool is a dedicated area of main memory (RAM) within the z/OS address space, managed by a database system (like DB2 for z/OS or IMS ...
Database Descriptor
A Database Descriptor (DBD) is a control block in IBM's Information Management System (IMS) that defines the physical structure of an IMS database. It...
Database Manager
A Database Manager, often referred to as a Database Management System (DBMS) component, is the core software responsible for organizing, storing, retr...
Database Mirroring - Real-time copy
Database mirroring, in the z/OS environment, refers to the continuous, real-time replication of database changes from a primary system or storage volu...
Datagram
A datagram is a self-contained, independent unit of data that carries enough information to be routed from a source to a destination without requiring...
DATACLAS - Data Class
A Data Class (`DATACLAS`) is a component of the z/OS Storage Management Subsystem (SMS) that defines a set of attributes for a dataset, such as record...
DATAMOVE
`DATAMOVE` refers to a class of utilities or specific software products on `z/OS` designed for the efficient and reliable transfer of data between var...
Dataset Contention
Dataset contention in z/OS occurs when multiple `jobs`, `tasks`, or `address spaces` attempt to access the same `dataset` simultaneously, and their ac...
Dataset Control Block
The Dataset Control Block (DCB) is a critical data structure residing in virtual storage that contains comprehensive information about a specific data...
Dataset Label
A dataset label is a block of identification and descriptive information associated with a dataset on an IBM z/OS system. It contains critical metadat...
Dataset Organization - Structure type
Dataset organization refers to the physical and logical structure by which records within a dataset are arranged and accessed on a storage device, pri...
Dataset Protection - Security controls
Dataset protection in z/OS refers to the security mechanisms and policies implemented to control and restrict access to datasets stored on direct acce...
Date Format
Date format refers to the standardized representation of calendar dates within IBM mainframe systems, z/OS applications, and data storage. It defines ...
DATEFMT
`DATEFMT` is a parameter used in various IBM mainframe utilities and programs, primarily DFSORT and ICETOOL, to specify the format of date fields with...
DATETIME
In mainframe computing, a datetime value represents a specific point in time, combining both a date (year, month, day) and a time (hour, minute, secon...
Datum
In the mainframe context, a **datum** refers to a single, atomic piece of information or a single data point. It is the smallest unit of data that can...
DB2 Catalog
The DB2 Catalog is a fundamental set of system tables within a DB2 for z/OS subsystem that stores all metadata about the DB2 environment. It contains ...
DB2 Connect
DB2 Connect is a software product that enables applications running on distributed platforms (such as Linux, Unix, Windows, Java, .NET) to access and ...
DB2 Directory
The DB2 Directory is a set of critical internal control tables within the DB2 subsystem that stores essential metadata about the entire DB2 environmen...
DB2 Governor
The DB2 Governor is a crucial component within DB2 for z/OS designed to monitor and control the resource consumption of SQL statements and application...
DB2 PM - Performance Monitor
DB2 PM (Performance Monitor) is a crucial IBM product designed to monitor, analyze, and report on the performance of Db2 for z/OS subsystems. It colle...
DB2 Precompiler
The DB2 Precompiler is a utility in the IBM z/OS environment that processes application programs containing embedded SQL statements. Its primary purpo...
DB2 Subsystem
In the z/OS environment, a **DB2 Subsystem** is a specific, independently operating instance of the IBM Db2 for z/OS relational database management sy...
DBA - Database Administrator
A Database Administrator (DBA) on IBM mainframe systems is a highly specialized professional responsible for the design, implementation, maintenance, ...
DBADM
`DBADM` (Database Administrator authority) is a specific authorization level within IBM Db2 for z/OS that grants a user comprehensive administrative c...
DBAT - Database Access Thread
A Database Access Thread (DBAT) is a specific type of thread within DB2 for z/OS that handles connections and requests originating from distributed cl...
DBCLOB - Double Byte Character CLOB
`DBCLOB` (Double Byte Character Large Object) is a data type in IBM Db2 for z/OS designed to store extremely large strings of double-byte character se...
DBCS - Double Byte Character Set
DBCS (Double Byte Character Set) is a character encoding scheme predominantly used on IBM mainframes to represent characters from languages that requi...
DBCTL - Database Control
DBCTL (Database Control) is a feature within IBM's IMS (Information Management System) that allows CICS (Customer Information Control System) applicat...
DBD - Database Description
A DBD (Database Description) is an IMS (Information Management System) control block that defines the physical and, optionally, logical structure of a...
DBID - Database Identifier
A DBID (Database Identifier) is a unique, internal 2-byte binary integer assigned by IBM IMS (Information Management System) to each defined database....
DBRM - Database Request Module
A Database Request Module (DBRM) is a member in a partitioned dataset (PDS or PDSE) that contains the SQL statements extracted from an application pro...
DBSPJAVA - Stored procedure Java
A Java stored procedure (often referred to as DBSPJAVA in the context of DB2 for z/OS) is a program written in Java that is stored in the DB2 catalog ...
DC
DC is an acronym with two primary meanings in the mainframe context: 1. **Data Center:** A physical facility housing computer systems, including main...
DCA - Document Content Architecture
Document Content Architecture (DCA) is a set of IBM architectures that define the structure and content of documents, enabling their interchange and p...
DCBE - Data Control Block Extension
The Data Control Block Extension (DCBE) is a control block in z/OS that provides additional parameters and capabilities beyond those found in the stan...
DCD - Device Characteristics Directory
The Device Characteristics Directory (DCD) is an in-memory control block structure within z/OS that contains detailed technical specifications and cap...
DCF - Document Composition Facility
DCF (Document Composition Facility) is an IBM mainframe program product used for high-quality, batch-oriented document formatting and text processing....
DCI - Database Call Interface
The Database Call Interface (DCI) refers to the programmatic method used by application programs, primarily in IBM's Information Management System (IM...
DCOLLECT - Data Collector
`DCOLLECT` (Data Collector) is an IBM utility within `DFSMS` (Data Facility Storage Management Subsystem) used to gather comprehensive information abo...
DCS - Distributed Computing Services
In the context of IBM z/OS, Distributed Computing Services (DCS) refers to the capabilities and mechanisms by which the mainframe platform provides, c...
DD Card - Data Definition card
A DD (Data Definition) card is a Job Control Language (JCL) statement used to define and describe data sets or other I/O resources required by a progr...
DDF - Distributed Data Facility
The Distributed Data Facility (DDF) is a core component of DB2 for z/OS that enables distributed relational database access. It allows remote applicat...
DDL - Data Definition Language
DDL (Data Definition Language) is a subset of SQL used in IBM DB2 for z/OS to define, modify, and manage the structure of database objects. It allows ...
DDM - Distributed Data Management
Distributed Data Management (DDM) is an architecture that enables applications on one system to access data located on another, remote system in a tra...
Deadlock Detector
A Deadlock Detector is a system component or utility within a mainframe environment (such as z/OS, DB2, or IMS) designed to identify situations where ...
Deallocation
Deallocation in z/OS is the process of releasing system resources that were previously allocated to a job, step, or program. This action makes the res...
Debug
In the mainframe and z/OS environment, debugging is the systematic process of identifying, analyzing, and resolving errors (often called **bugs**) in ...
Debug Mode
Debug mode, in the context of z/OS, refers to the execution of a program or system component with enhanced diagnostic capabilities enabled. This typic...
Debug Tool
IBM Debug Tool is an interactive source-level debugger for applications running on z/OS. It allows developers to step through program execution, inspe...
Debugger
A debugger is a specialized software tool used by developers and system programmers on z/OS to identify, analyze, and resolve errors (bugs) in applica...
DEC - Digital Equipment Corporation
Digital Equipment Corporation (DEC) was a pioneering American computer company, prominent from the 1960s through the 1990s, known primarily for its mi...
Decimal
In the context of IBM mainframe systems and z/OS, "Decimal" refers to the base-10 number system used for representing numeric data, primarily for busi...
Decision - Conditional branch
A conditional branch is a fundamental control flow mechanism in mainframe programming that alters the sequential execution path of a program based on ...
Decision Support - Analysis tools
In the mainframe context, Decision Support - Analysis tools refer to specialized software and utilities designed to extract, transform, and analyze la...
Declaration
In the context of mainframe programming, particularly COBOL, declaration refers to the process of defining data items (variables) within a program, sp...
Declarative - Specifying what not how
In the mainframe context, "declarative" refers to a programming or configuration style where you describe *what* you want to achieve rather than *how*...
Decode
In the mainframe context, **decoding** refers to the process of converting data from one encoded format or character set into another, typically to ma...
Decrement
In the mainframe context, **decrement** refers to the operation of decreasing the value of a numeric variable, register, or counter by a specific amou...
Decryption
Decryption, in the z/OS environment, is the process of converting encrypted, unreadable data back into its original, intelligible form using a specifi...
Dedicated
In the mainframe context, "dedicated" refers to a resource (such as a device, volume, processor, or memory region) that is exclusively allocated for a...
Distributed Execution Environment
A Distributed Execution Environment (DEE) on z/OS refers to the architectural patterns and technologies that enable z/OS-based applications and data t...
Default
In the context of mainframe and z/OS, a **default** refers to a pre-assigned value, setting, or action that is automatically used by the system, an ap...
Deferral
In the mainframe context, **deferral** refers to the act of postponing an operation, task, or resource request until a later time or until specific co...
Deferred Update - Delayed write
In mainframe systems, a **deferred update**, also known as a **delayed write**, is a strategy where changes to data (e.g., in a database or file) are ...
DD Statement
A Data Definition (DD) statement in JCL (Job Control Language) is used to define and describe the characteristics of a data set or other I/O resources...
Degradation
In the context of IBM z/OS, **degradation** refers to a measurable reduction in the performance of a system, application, or specific workload, often ...
DEK - Data Encryption Key
A Data Encryption Key (DEK) is a symmetric cryptographic key used specifically to encrypt and decrypt the actual user data (payload) on IBM z/OS syste...
Delegate
In the context of IBM z/OS, "delegate" primarily refers to the act of assigning or transferring authority, responsibility, or access rights from one e...
DELETE
In the mainframe context, `DELETE` refers to the operation of removing data, which can range from individual records within a file or database, to ent...
Delimiter
A delimiter is a character or sequence of characters used to mark the beginning or end of a data item, field, or statement, or to separate distinct el...
Delivery
In the context of IBM z/OS, **delivery** refers to the process of transmitting and making available job output, messages, or data files to their desig...
Delta
In the mainframe context, a **delta** refers to the difference or change between two versions of a resource, such as source code, data, or configurati...
Demand - Immediate requirement
In the mainframe context, "demand - immediate requirement" refers to a critical need for rapid processing, resource allocation, or system response tha...
Demand Paging
Demand paging is a memory management technique used in z/OS where pages of a program or data are loaded into real storage only when they are actually ...
Demarcation
In the context of IBM z/OS and enterprise computing, **demarcation** refers to the establishment of clear boundaries or divisions between different sy...
Demilitarized Zone
A Demilitarized Zone (DMZ) is a perimeter network that protects an organization's internal local area network (LAN) from untrusted external networks, ...
Denial of Service - DoS attack
A Denial of Service (DoS) attack on a mainframe system aims to make a z/OS system, its applications, or network resources unavailable to legitimate us...
Dense
In the context of mainframe computing, "dense" primarily refers to data that is stored or represented in a compact, space-efficient format. This appro...
Dependency
In the mainframe context, a dependency refers to a required relationship where one component, program, job, or resource relies on another to function ...
Deploy
In the mainframe context, "deploy" refers to the process of installing, activating, and making software components, applications, or configurations av...
Deployment
In the z/OS environment, deployment refers to the structured process of installing, configuring, and making available software components, application...
Deprecated
In the context of IBM mainframe systems and z/OS, a "deprecated" feature, command, API, or component is one that is no longer recommended for use by I...
Depth - Level in hierarchy
In the context of mainframe and z/OS, "depth" refers to the number of levels or layers from the root (topmost element) of a hierarchical structure to ...
Deque - Double-ended queue
A Deque (Double-ended queue) is a linear data structure that permits elements to be added or removed from either the front (head) or the back (tail). ...
Dequeue
Dequeue, in the mainframe context, refers to the act of removing an item from a queue or releasing a previously acquired serially reusable resource. I...
Dereference
In the context of mainframe programming, **dereferencing** is the operation of accessing the data value stored at the memory address indicated by a po...
Derivation
In the context of mainframe and z/OS, **derivation** refers to the process of creating new data values or fields by applying specific rules, calculati...
Derived
In the mainframe context, **derived data** refers to data values that are not directly stored but are computed or calculated from one or more existing...
DES - Data Encryption Standard
DES, or Data Encryption Standard, is a symmetric-key block cipher algorithm published by NIST in 1977. On IBM mainframes and z/OS, it was historically...
Descendant
In mainframe computing, a **descendant** refers to an entity that is subordinate to another entity (its **parent**) within a hierarchical structure. I...
Descriptor
In the mainframe context, a descriptor is a structured piece of information that defines the attributes, characteristics, and properties of a specific...
Deserialize
Deserialization, in the mainframe context, is the process of converting a stream of bytes or a structured data format (like JSON, XML, or a flat file ...
Designate
In the context of IBM z/OS, "designate" refers to the act of explicitly assigning a specific purpose, role, resource, or attribute to a system compone...
Destination Name
A Destination Name is a symbolic identifier used within IBM mainframe systems, primarily z/OS, to specify a target location or resource for data, mess...
Destruct - Cleanup operation
In the context of mainframe systems, "Destruct" refers to the essential process of performing **cleanup operations** at the end of a program, transact...
Detail Record
A `detail record` typically represents an individual transaction, event, or specific piece of information within a dataset or file, often used as inpu...
Deterministic
In the mainframe context, a deterministic process or system is one that, given the same initial state and identical inputs, will consistently produce ...
Detour - Alternative path
In the context of mainframe programming and z/OS, a "detour" refers to a deviation from the normal, sequential execution path of a program or system p...
Development
In the mainframe context, development refers to the entire process of designing, coding, testing, and implementing software applications or system com...
Device Class
In z/OS, a **Device Class** is a logical grouping of I/O devices that share similar characteristics, capabilities, and operational attributes. It prov...
Device Driver
In the mainframe z/OS environment, a device driver refers to the low-level software component, often integrated within the operating system's I/O Supe...
Device ID - Device Identifier
In the z/OS environment, a Device ID (or Device Identifier) is a unique hexadecimal address assigned to a specific I/O device, such as a disk drive (D...
Device Independence
Device independence in the z/OS environment refers to the ability of application programs to access and process data without needing to know the speci...
Device Support
Device Support refers to the collection of software components within the z/OS operating system that enable it to recognize, control, and communicate ...
DEVSERV - Device Services
`DEVSERV` (Device Services) is a powerful z/OS operator command used to display detailed information about the status, characteristics, and allocation...
DEVTYPE - Device Type
DEVTYPE, or Device Type, is an attribute or parameter used in IBM z/OS to specify the *class* or *category* of an I/O device required for a dataset or...
DFDSM - Data Facility Data Set Management
DFDSM, or Data Facility Data Set Management, is a core component of IBM's DFSMS (Data Facility Storage Management Subsystem) on z/OS. It provides comp...
DFH
`DFH` is the standard three-character prefix used by IBM for most CICS Transaction Server components, modules, macros, messages, and some system trans...
DFHCMACD
`DFHCMACD` is a core CICS system module that contains the macro definitions for CICS command-level statements. It is primarily used by the CICS transl...
DFHCOMMAREA
`DFHCOMMAREA` (CICS Communication Area) is a block of transient storage used by CICS application programs to pass data between programs, typically whe...
DFHEIB - Execute Interface Block
The `DFHEIB` (Execute Interface Block) is a CICS control block that provides an application program with information about the current task and the re...
DFHEIBLK - EIB block
The CICS **E**xecution **I**nterface **B**lock (`DFHEIBLK`) is a crucial control block that provides a standard interface between an application progr...
DFHSIT - System Initialization Table
The System Initialization Table (SIT) is a crucial CICS control table that defines the operating parameters and characteristics for a CICS region at s...
DFHTCT - Terminal Control Table
The Terminal Control Table (DFHTCT) is a fundamental CICS control block that defines all terminals, logical units, and associated communication charac...
DFLT - Default
In mainframe systems, "default" refers to a pre-defined or automatically assumed value, setting, or behavior that is used when no explicit alternative...
DFS - Distributed File System
The z/OS Distributed File Service (DFS) is a component of z/OS UNIX System Services that enables file sharing between z/OS and other operating systems...
DFSORT - Data Facility Sort
DFSORT, or Data Facility Sort, is a high-performance, general-purpose utility program for IBM z/OS that efficiently sorts, merges, copies, and summari...
DFSS - Data Facility Storage Services
DFSS (Data Facility Storage Services) is a fundamental component of the IBM z/OS Data Facility Storage Management Subsystem (DFSMS). It provides the c...
DFSMS/MVS
DFSMS/MVS (Data Facility Storage Management Subsystem for MVS) is a core component of IBM z/OS that provides automated, policy-based management of dat...
DFT - Distributed Function Terminal
A Distributed Function Terminal (DFT) is a type of IBM 3270-compatible terminal connection that allows a single physical terminal device to establish ...
DHCP - Dynamic Host Configuration Protocol
Dynamic Host Configuration Protocol (DHCP) is a network protocol used to automatically assign IP addresses and other network configuration parameters ...
Diagnostics
In the z/OS environment, diagnostics refers to the systematic process and specialized tools used to identify, analyze, and resolve problems within the...
Dialect
In the context of mainframe computing, a dialect refers to a specific variant or implementation of a programming language (like COBOL, PL/I, or SQL) t...
Dialog
In mainframe computing, particularly within z/OS, a **dialog** refers to an interactive exchange between a user and an application, often spanning mul...
Dictionary
In the context of IBM mainframe systems, a Dictionary (often referred to as a Data Dictionary or Data Directory) is a centralized repository of metada...
Difference
In the context of IBM z/OS, "difference" refers to the observable variance or disparity between two or more items, such as datasets, program versions,...
Digital - Discrete numeric representation
In the context of IBM mainframe systems and z/OS, "digital - discrete numeric representation" refers to the fundamental principle that all numerical d...
Digital Certificate
A digital certificate is an electronic credential used within z/OS to verify the identity of users, applications, or systems, and to enable secure, en...
Digital Signature
A digital signature is a mathematical scheme used to verify the authenticity and integrity of digital messages, documents, or software. In the mainfra...
Dimension
In the context of data warehousing and business intelligence on IBM z/OS, a dimension is a structural component that categorizes and describes data in...
DIR - Directory
In the z/OS environment, a directory primarily refers to a special type of file within the z/OS UNIX System Services (USS) hierarchical file system th...
Direct Access - Non-sequential storage
Direct access storage refers to the ability to retrieve or store data directly at any specific location on a storage device without having to read thr...
Direct Connect
A "Direct Connect" in the mainframe context refers to a dedicated, unmediated communication path established between two components, systems, or devic...
Direct Insert
A database operation, primarily in DB2 for z/OS, that allows data to be inserted into a table while bypassing the standard logging mechanism. Its main...
Direction - Forward or backward
In mainframe computing, "direction - forward or backward" refers to the sequential order in which data records are processed, accessed, or traversed w...
Directive
In mainframe programming, a directive is an instruction embedded within source code that guides a compiler, assembler, or preprocessor on how to proce...
DIRMAINT - Directory Maintenance
`DIRMAINT` is a key component of the `z/VM` operating system on IBM mainframes, providing an automated and secure way to manage the `z/VM` user direct...
Dirty
In mainframe and z/OS contexts, "dirty" describes data that has been modified in memory (e.g., within a buffer, cache, or virtual storage page) but ha...
Dirty Page
A **dirty page** in z/OS refers to a 4KB block of virtual storage that resides in real storage (main memory) and has been modified by a program or the...
Dirty Read
A Dirty Read, also known as an Uncommitted Read, occurs when a transaction reads data that has been modified by another transaction but has not yet be...
Disable
In the mainframe context, to **disable** means to temporarily or permanently render an entity (such as a resource, function, or user access) inoperab...
Disarm - Deactivate
In z/OS, "disarm" or "deactivate" refers to the controlled process of making a system component, resource, or function inactive, non-operational, or n...
Disassemble
In the mainframe context, **disassembly** is the process of converting machine code (executable instructions, typically found in a load module or prog...
Discard - Throwing away
In the context of mainframe and z/OS systems, "discarding" refers to the deliberate act of ignoring, releasing, or removing data, messages, or resourc...
Disconnect
In the mainframe context, a **disconnect** refers to the termination of an established logical or physical connection between two entities, such such ...
Discovery
In the mainframe and z/OS context, **Discovery** refers to the process of identifying and cataloging available system resources, configurations, and d...
Discrete
In the context of mainframe systems, "discrete" refers to an individual, distinct, and separately identifiable entity or component, often a resource, ...
Discriminator
A discriminator, in the context of mainframe data processing, is a specific field or value within a data record, message, or control block that serves...
Disjoint
In the context of IBM mainframe systems and z/OS, "disjoint" or "non-overlapping" describes two or more entities, such as memory regions, data areas, ...
Disk Array
A **Disk Array** in the mainframe context refers to a high-performance, fault-tolerant storage subsystem composed of multiple physical disk drives (of...
Disk Mirroring
Disk mirroring, also known as RAID-1, is a data redundancy technique in mainframe environments where data is simultaneously written to two or more sep...
Dismount
In the context of IBM z/OS, dismounting a volume refers to the process of logically detaching a storage volume (typically a magnetic tape cartridge or...
Dispatch
In the context of IBM z/OS, **dispatching** is the fundamental operating system process by which the z/OS dispatcher component selects the next ready ...
Dispatcher
The Dispatcher is a fundamental component of the z/OS operating system kernel responsible for allocating CPU resources to ready units of work, primari...
Dispatching Priority
Dispatching priority is a numerical value assigned to an address space, task, or work unit in z/OS that determines its precedence for CPU allocation. ...
Display
In the mainframe context, "Display" refers to the act of presenting information to a user, operator, or log file, typically via a 3270 terminal, an op...
Display Station - Terminal
A display station, commonly referred to as a terminal in the mainframe context, is an input/output device used by end-users to interact with mainframe...
Disposition
In z/OS JCL, the final disposition specifies the action the system should take with a dataset after the job step that used it completes. It dictates w...
Disruptive Event
A disruptive event in a mainframe environment is an occurrence, either planned or unplanned, that causes an interruption to normal system operations, ...
Disseminate
In the context of IBM z/OS and mainframe systems, "disseminate" refers to the process of distributing information, data, reports, messages, or softwar...
Distance Vector - Routing algorithm
A Distance Vector routing algorithm is a class of dynamic routing protocols where each router periodically shares its entire routing table with its di...
Distortion
In the context of mainframe systems, distortion refers to the unintended alteration or corruption of data or signals during processing, storage, or tr...
Distribute
In the mainframe context, "distribute" refers to the process of sending data, reports, software components, or workload requests to multiple designate...
Distributed
In the context of IBM mainframe systems and z/OS, "distributed" refers to computing resources, data, or processes that are spread across multiple inte...
Distributed Database
A distributed database is a database system where data is stored across multiple physical locations (nodes or sites) but is logically presented as a s...
Distributed Lock Manager
In the context of IBM z/OS, a Distributed Lock Manager (DLM) refers to the mechanism and services that coordinate and manage locks across multiple z/O...
Distributed Relational Database Architecture (DRDA) Protocol
The Distributed Relational Database Architecture (DRDA) is a set of protocols that enables distributed relational database access, allowing applicatio...
Distributed Transaction
A distributed transaction is a logical unit of work that spans multiple independent resource managers (e.g., databases, message queues) across differe...
Distribution
In the mainframe context, **distribution** primarily refers to the automated process of delivering output (such as reports, documents, and data files)...
Distribution List
In the context of IBM z/OS, a Distribution List refers to a predefined group of recipients or destinations used to route output, messages, or data to ...
Divergence
Divergence, in the mainframe context, refers to the state where components, configurations, data, or processes within a z/OS environment deviate from ...
Diversity
In the context of IBM mainframe systems, "diversity" refers to the z/OS operating system's inherent capability to support a wide array of programming ...
Division
In COBOL, a program is logically structured into four main divisions: `IDENTIFICATION`, `ENVIRONMENT`, `DATA`, and `PROCEDURE`. These divisions organi...
DL/I - Data Language Interface for IMS
DL/I (Data Language Interface) is the programming interface used by application programs to access and manipulate data stored in IBM's IMS (Informatio...
DLI - Database Language Interface
DLI, or Database Language Interface, is the programmatic interface used by application programs (primarily COBOL, PL/I, and Assembler) to interact wit...
DLL - Dynamic Link Library
A Dynamic Link Library (DLL) in the z/OS environment is a type of load module containing re-entrant, shareable code and data that is loaded into memor...
DLM - Distributed Lock Manager
A Distributed Lock Manager (DLM) in the z/OS environment is a critical component that provides serialization and resource management across multiple z...
DLPAR - Dynamic LPAR
DLPAR, or Dynamic LPAR, is a feature on IBM zSystems that allows system administrators to dynamically add, remove, or modify hardware resources (such ...
DLQ - Dead Letter Queue
A Dead Letter Queue (DLQ) is a special queue used by a message queuing system, such as IBM MQ for z/OS, to store messages that cannot be delivered to ...
DM - Data Manager
In the mainframe context, a Data Manager (DM) refers to a system component or software responsible for the organized storage, retrieval, update, and d...
DML - Data Manipulation Language
Data Manipulation Language (DML) is a family of programming languages used to retrieve, insert, update, and delete data in a database. In the z/OS env...
DMZ - Demilitarized Zone
A Demilitarized Zone (DMZ) is a perimeter network segment that separates an organization's internal, trusted network from an untrusted external networ...
DN - Distinguished Name
A Distinguished Name (DN) is a unique identifier for an entry within an LDAP (Lightweight Directory Access Protocol) directory. In the mainframe and z...
DNS - Domain Name System
The Domain Name System (DNS) on z/OS is a hierarchical and distributed naming system that translates human-readable hostnames (e.g., `www.example.com`...
Document
In the context of IBM mainframes and z/OS, a "document" typically refers to a **dataset**, which is a named collection of related data or programs sto...
Documentation - Reference Materials
In the mainframe context, documentation refers to the comprehensive set of written materials that describe the design, implementation, operation, and ...
Domain
In the context of IBM mainframe systems, a **domain** refers to a logical grouping or scope of control, resources, or authority within a system, netwo...
Domain Name
A domain name is a human-readable identifier used to locate resources on a network, such as servers or services, and is resolved into an IP address by...
Dormant
In the mainframe context, "dormant" describes a resource, task, or process that is currently inactive or suspended but remains loaded in memory or ava...
DOS - Disk Operating System
DOS (Disk Operating System) refers primarily to a family of single-user, single-tasking operating systems designed for personal computers, most notabl...
Double Byte Character
A Double Byte Character (DBC) is a character represented by two bytes of storage, primarily used on IBM mainframes and z/OS to support character sets ...
Doubleword
A doubleword is a fundamental unit of data storage and processing in IBM mainframe systems, consisting of eight bytes (64 bits). It is primarily used ...
Down - Not operational
In the mainframe context, "down" or "not operational" describes a state where a system, subsystem, application, component, or service is unavailable, ...
Download
In the mainframe context, "download" refers to the process of transferring data or files from a mainframe system (the remote host) to a client worksta...
Downtime
Downtime refers to a period during which a mainframe system, application, or component is unavailable for use by its intended users or processes. In t...
DP - Data Processing
In the mainframe context, `Data Processing` refers to the systematic collection, manipulation, and transformation of raw data into meaningful informat...
DPI - Dots Per Inch
DPI (Dots Per Inch) is a measure of spatial printing resolution, indicating the number of individual dots of ink or toner a printer can place within a...
DPMOD - Distributed Print Model
DPMOD, or Distributed Print Model, is a strategy within z/OS for managing and distributing print output (SYSOUT) from the mainframe to network-attache...
DR - Disaster Recovery
Disaster Recovery (DR) in the mainframe context refers to the comprehensive process and set of procedures designed to restore critical z/OS systems, a...
Draft - Preliminary Version
In the context of IBM mainframe systems and z/OS, a "draft" or "preliminary version" refers to an early, incomplete, or unapproved iteration of a prog...
Drag - Moving with pointer
This term primarily describes an action in graphical user interfaces (GUIs) where a user selects an object with a mouse or pointer and moves it to a n...
Drain
In the mainframe context, "draining" refers to the controlled process of stopping new work from being accepted by a system, subsystem, or resource, wh...
DRDA - Distributed Relational Database Architecture
DRDA (Distributed Relational Database Architecture) is an open, client-server architecture that defines the protocols for distributed relational datab...
Drive
In the mainframe context, a **drive** refers to a physical or logical storage unit, primarily a Direct Access Storage Device (DASD) or a tape drive, u...
Driver
In the z/OS context, a driver refers to a specialized software component or interface program that facilitates communication, control, or data exchang...
DROP
In the context of IBM mainframes and z/OS, `DROP` refers to the action of permanently deleting a defined object or resource from a system. This operat...
DS - Data Set
A data set (DS) is the fundamental unit of data storage and organization in IBM z/OS, analogous to a file in other operating systems. It represents a ...
DSA - Data Set Association
Data Set Association (DSA) in z/OS refers to the process of logically connecting a program or job step to a specific data set, making it available for...
DSECT - Dummy Section
A DSECT (Dummy Section) is an assembly language construct used to define the symbolic layout of a data structure without actually allocating storage f...
DSN - Data Set Name
A Data Set Name (DSN) is a unique, hierarchical identifier used by the z/OS operating system to locate and manage a collection of related data on a st...
DSNDB01
DSNDB01 is the **DB2 directory database**, a critical internal database within an IBM Db2 for z/OS subsystem. It stores essential metadata and control...
DSNDB06
`DSNDB06` is a critical system database within DB2 for z/OS that houses the DB2 Catalog and the DB2 Directory. It is fundamental for the operation and...
DSORG - Data Set Organization
`DSORG` (Data Set Organization) is a critical attribute on IBM z/OS that defines the physical structure and access method of a data set. It dictates h...
DSP - Digital Signal Processor
A Digital Signal Processor (DSP) is a specialized microprocessor designed to perform rapid mathematical operations on digitized real-world signals, su...
DSPSERV - Data Space Services
`DSPSERV` is a z/OS macro instruction that provides services for creating, managing, and accessing data spaces and hiperspaces. It allows programs to ...
DSPSTATS - Dispatcher Statistics
`DSPSTATS` (Dispatcher Statistics) is a z/OS console command used to display real-time statistics about the z/OS dispatcher's activity. It provides cr...
DTE - Data Terminal Equipment
In the context of IBM mainframes and z/OS, **Data Terminal Equipment (DTE)** refers to the end-user device or application that acts as the source or d...
DTF - Define The File
DTF (Define The File) is a control statement used in **DOS/VSE** (Disk Operating System/Virtual Storage Extended) to define the characteristics of a f...
DTR - Data Terminal Ready
DTR (Data Terminal Ready) is a control signal in serial communication, typically part of the RS-232 standard, used by a Data Terminal Equipment (DTE) ...
Dual
In the context of IBM mainframe systems, particularly z/OS, "Dual" refers to the practice of maintaining two identical, synchronized copies of a resou...
Dual Mode
In the context of IBM z/OS, "Dual Mode" most commonly refers to the capability of a program or system component to operate in two distinct **addressin...
Dub - Copy or duplicate
The term "Dub" is not a standard or recognized technical term within the IBM mainframe and z/OS ecosystem to denote the action of "copying" or "duplic...
DUMPDS - Dump Data Set
A DUMPDS, or Dump Data Set, is a specialized data set on IBM z/OS used to store a snapshot of a system's memory, registers, and control blocks at a sp...
Duplex - Two-way communication
In the context of IBM mainframe systems and z/OS, **duplex** refers to a communication mode that allows for simultaneous, two-way data transmission be...
Duplicate
The act of creating an **exact copy** of an existing entity, such as a data set, file, record, program, or storage volume, ensuring that the replica i...
Duplicate Key
A duplicate key refers to a record identifier or index value that is not unique within a dataset, file, or database table. In mainframe systems, it si...
Duration
In the mainframe and z/OS context, **duration** refers to the length of time an activity, process, or resource allocation persists. It is a critical m...
DW - Data Warehouse
A Data Warehouse (DW) in the mainframe context is a centralized, subject-oriented repository of integrated, time-variant, and non-volatile data primar...
Dwell Time - Residence Period
Dwell time, also known as residence period, refers to the total duration a specific entity (e.g., a transaction, a job step, a data record, or a proce...
DWIM - Do What I Mean
"Do What I Mean" (DWIM) is a design philosophy where a system attempts to infer a user's intent and perform the most likely desired action, even if th...
DXC - Data Transfer Control
DXC, or Data Transfer Control, is a VTAM (Virtual Telecommunications Access Method) macro instruction and its associated control block used by applica...
Dynamic
In the mainframe context, "dynamic" refers to the ability of a system, program, or resource to be modified, allocated, or bound during program executi...
Dynamic Allocation
Dynamic allocation is a z/OS mechanism that allows application programs or system utilities to allocate and deallocate datasets, devices, or other sys...
Dynamic Backout
Dynamic backout is an automatic process in mainframe transactional systems (like CICS, IMS, and DB2) that reverses all changes made by an incomplete o...
Dynamic Link - Runtime Connection
A dynamic link, in the z/OS context, refers to the process where a program resolves and loads external routines or modules during its execution, rathe...
Dynamic Loading
Dynamic loading in the z/OS environment refers to the process of loading an executable program module, subroutine, or data into memory during the exec...
Dynamic Modification - Runtime Change
Dynamic modification, in the context of z/OS and mainframe systems, refers to the ability to alter system components, application resources, or config...
Dynamic Plan Selection
Dynamic Plan Selection, in the context of IBM Db2 for z/OS, refers to the capability to choose a specific Db2 package (and thus its associated access ...
Dynamic Reconfiguration
Dynamic Reconfiguration refers to the capability within IBM z/OS and its underlying hardware to modify system resources, hardware components, or softw...
Dynamic SQL
Dynamic SQL in the z/OS context, primarily within DB2 for z/OS, refers to SQL statements that are constructed and prepared for execution at applicatio...
DYNALLOC - Dynamic Allocation
Dynamic Allocation, often referred to as DYNALLOC, is a z/OS facility that allows an executing program to allocate or deallocate system resources, pri...
DYNAM - Dynamic Call
`DYNAM` (Dynamic) is a COBOL compiler option that enables a program to call another program whose name is not known until runtime. Instead of linking ...
Data Compaction
Data compaction, in the context of z/OS, refers to the process of reducing the physical storage size of data. This is achieved by applying algorithms ...
DASD
Magnetic disk storage devices that allow direct access to any data location without sequential searching. DASD is the primary online storage medium fo...
Dataset
A collection of related data records stored as a unit on mainframe storage, equivalent to a file in other operating systems. Datasets are the fundamen...
DB2
IBM's enterprise-class relational database management system for z/OS, supporting SQL and providing scalable, secure data management for mission-criti...
DCB
A control structure containing information about dataset characteristics such as record format, block size, record length, and access method. The DCB ...
DFSMS
IBM's integrated storage management system providing automated space management, backup, migration, and data protection services for z/OS. DFSMS simpl...
DRDA
A protocol enabling database communication between different platforms and DBMS products, allowing distributed DB2 access and remote SQL execution acr...
DASD - Direct Access Storage Device
DASD, or Direct Access Storage Device, is a fundamental type of non-volatile storage in IBM mainframe environments, allowing data to be accessed direc...
Data Class
A Data Class is a component of the z/OS Storage Management Subsystem (SMS) that defines a set of physical and logical attributes for a dataset. It spe...
Data Control Block
A Data Control Block (DCB) is a memory-resident control block used by z/OS and its access methods to describe the attributes of a dataset. It contains...
Data Definition (DD) Statement
A Data Definition (DD) statement is a fundamental Job Control Language (JCL) statement used in IBM z/OS to define and allocate input/output resources ...
Data Facility
Data Facility refers to a suite of IBM software products within the z/OS environment designed to manage, store, protect, and optimize access to data. ...
Data In Virtual
Data In Virtual (DIV) is an IBM z/OS access method that allows an application program to treat data residing on a Direct Access Storage Device (DASD) ...
Data Management
In the z/OS environment, data management refers to the comprehensive set of system functions and services responsible for organizing, storing, retriev...
Data Mover
In the mainframe context, a Data Mover is a specialized software facility or component designed to efficiently and reliably transfer large volumes of ...
Data Set
A fundamental unit of data storage on IBM mainframe systems running z/OS, representing a collection of logically related records. It is the mainframe ...
Data Space
A Data Space is a block of virtual storage that an `address space` can create and use to store data. Unlike an `address space`, a Data Space contains ...
DB2 - Database 2
DB2 (Database 2) is IBM's flagship relational database management system (RDBMS) specifically designed for the z/OS mainframe platform. It provides a ...
DCB - Data Control Block
A Data Control Block (DCB) is an in-memory control block used by z/OS access methods to manage and describe the characteristics of a data set during I...
DCE - Data Communication Equipment
In the context of IBM mainframes and z/OS, Data Communication Equipment (DCE) refers to devices that establish, maintain, and terminate data transmiss...
DDNAME - Data Definition Name
A `DDNAME` (Data Definition Name) is a symbolic name used in JCL (Job Control Language) to refer to a specific data set or other I/O resource required...
Deadlock
A deadlock is a condition in a multi-tasking or multi-threaded z/OS environment where two or more tasks are perpetually blocked, each waiting for a re...
Deferred Mount
Deferred mount is a z/OS allocation technique used primarily for tape devices, where the actual mounting of a tape volume by an operator is delayed un...
Defragmentation
Defragmentation on z/OS refers to the process of reorganizing data on Direct Access Storage Device (DASD) volumes to consolidate scattered data extent...
Destination
In the context of IBM z/OS and mainframe systems, a destination refers to the specific target or location where output, messages, or data are directed...
Device
In the mainframe context, a device refers to a physical hardware unit that performs input or output operations, or both, for the system. These devices...
Device Allocation
Device allocation in z/OS is the process by which the operating system assigns specific hardware resources, such as disk drives (DASD), tape drives, o...
Device Number
In z/OS, a device number (also known as a Unit Address or UCB address) is a unique hexadecimal identifier assigned to a specific hardware device (such...
DFP - Data Facility Product
DFP (Data Facility Product) was a core component of IBM's MVS operating system, responsible for fundamental data management services for datasets. It ...
DFSMS - Data Facility Storage Management Subsystem
DFSMS (Data Facility Storage Management Subsystem) is a suite of z/OS components that provides automated, policy-driven management of data storage, ac...
DFSORT
DFSORT is IBM's high-performance sort, merge, and copy utility for the z/OS operating system. It is an essential component for batch processing, enabl...
DIF - Data Interchange Format
DIF (Data Interchange Format) is a text-based file format designed for exchanging tabular data between applications, primarily spreadsheet programs. I...
Directory
In the context of IBM z/OS, a **Directory** is a control block structure within a Partitioned Data Set (PDS) or Partitioned Data Set Extended (PDSE) t...
Disk
A physical storage device that uses magnetic platters to store data persistently. In the mainframe context, this primarily refers to **Direct Access S...
Distributed Processing
Distributed Processing, in the mainframe context, refers to an architecture where computing tasks, data, or application components are spread across m...
DIV - Data In Virtual
DIV (Data In Virtual) is a z/OS facility that allows an application to map a portion of a data set or an entire data set into its virtual storage, tre...
DLI - Data Language Interface
DLI, or Data Language Interface, is the application programming interface (API) used by programs to interact with IBM's Information Management System ...
Dump
A dump, in the mainframe context, is a snapshot of the contents of main storage (memory) and/or auxiliary storage at a specific point in time, written...
DATEFMT - Date Format parameter
`DATEFMT` is a parameter or option used in various IBM z/OS contexts to specify the format in which dates are presented, interpreted, or expected. Its...
DBADM - Database Administrator Authority
`DBADM` (Database Administrator authority) is a powerful authorization level within **DB2 for z/OS** that grants extensive control over a *specific* d...
Declarative
In the context of mainframe computing, a **declarative** approach focuses on *specifying what* needs to be achieved rather than *how* to achieve it. I...
DEE - Distributed Execution Environment
A Distributed Execution Environment (DEE) in the mainframe context refers to the infrastructure and mechanisms that allow z/OS systems to initiate, ma...
DEFINE
In the context of IBM z/OS, `DEFINE` refers to the process of formally creating, allocating, and specifying the attributes and characteristics of a re...
Definition - Specification or description
In the context of IBM mainframe systems and z/OS, a "definition" refers to the precise, structured description or specification of a resource, data st...
Dependent
In the context of IBM mainframe systems, a "dependent" entity is one whose successful execution, completion, or availability relies directly on the pr...
Deprecated - Obsolete but supported
In the context of IBM z/OS and related software, "deprecated" refers to a feature, function, API, or component that is still available and fully suppo...
Design
In the mainframe context, **design** refers to the structured planning and specification phase of developing or modifying systems, applications, datab...
Destination Name - Target identifier
A `destination name` or `target identifier` in mainframe systems is a symbolic or explicit name used to specify the intended recipient or endpoint for...
Destruct
In the mainframe context, a "destruct" or "cleanup operation" refers to the systematic process of releasing system resources, deallocating memory, clo...
Detail
In the mainframe context, a "detail" typically refers to a **detail record** or **detail line**. This is a single record or line of data that contains...
Detect - Discovering occurrence
In the context of IBM z/OS and mainframe systems, "detecting an occurrence" refers to the process of identifying and recognizing specific events, cond...
DETOUR
In the context of z/OS system programming, a "detour" refers to a mechanism that alters the normal sequential execution flow of a program, typically t...
Software Development
Software development on z/OS refers to the entire process of designing, coding, testing, deploying, and maintaining applications that run on IBM mainf...
DFHEIBLK
The `DFHEIBLK`, or Executive Interface Block, is a control block automatically provided by CICS to every application program. It contains critical inf...
Data Comparison Utilities
Data Comparison Utilities on z/OS are specialized software tools designed to identify and report differences between two datasets, members, or files. ...
Digest
A digest, often referred to as a cryptographic hash, is a fixed-size string of characters, typically hexadecimal, generated from an input data set, me...
Digital Data Representation
In the mainframe context, "digital" refers to the fundamental method by which all information—including numbers, characters, and machine instructions—...
Directly
In the context of IBM mainframe systems and z/OS, "directly" refers to the ability to access data or resources without sequentially traversing precedi...
Deactivation
Deactivation, often conceptually referred to as "disarming" in certain contexts, is the process of rendering a system component, resource, user, or fu...
Discard
In the context of mainframe systems, "discard" refers to the intentional act of ignoring, deleting, or releasing data, messages, or resources that are...
Disconnect - Terminating connection
In the mainframe context, "disconnect" refers to the process of terminating an active connection or session between two entities, such as a user termi...
Disruptive
Describes an action, change, or event within the mainframe environment that necessitates an interruption of service, such as a system restart (IPL), s...
Dissemination
In the context of IBM z/OS and mainframe systems, dissemination refers to the process of distributing data, reports, job output, system messages, or o...
Distance Vector
A class of routing algorithms, such as `Routing Information Protocol (RIP)`, used by `TCP/IP stacks` on z/OS to determine the optimal path for IP pack...
Distributed Relational Database - DRDA protocol
DRDA (Distributed Relational Database Architecture) is a set of open protocols that enables applications to access relational databases located on dif...
Domain - Area of authority
In the context of IBM z/OS, a **domain** refers to a logical grouping of resources, users, or systems over which a specific administrative entity, sec...
Double Byte Character Set
A Double Byte Character Set (DBCS) is a character encoding system where each character is represented by two bytes (16 bits), allowing for the represe...
Drive - Storage device
In the context of IBM mainframes and z/OS, a "drive" refers to a physical or virtual hardware component used for persistent data storage. This primari...
Driver - Control software
In the mainframe context, a "driver" (or control software) refers to a program or software component designed to initiate, manage, or facilitate inter...
Due
In the context of mainframe operations, "due" refers to the state or condition where a specific task, process, report, or system action is expected or...
Duplex
...
Dynamic Linking
Dynamic linking, in the mainframe context, is a mechanism where external program modules (subroutines, functions, or entire programs) are resolved and...
DB2 Tablespace Types
DB2 tablespace types define how data for one or more tables is physically stored and organized within a DB2 database on z/OS. They determine character...
DB2 Access Path Selection
DB2 Access Path Selection is the process by which the DB2 optimizer, a component of the DB2 database manager, determines the most efficient method to ...
E
Event and Condition Detection
In the mainframe context, Event and Condition Detection refers to the systematic process of identifying specific occurrences, states, or patterns with...
EAE - Enterprise Application Edition
EAE, often an acronym for **Enterprise Application Environment** (or sometimes referred to as Enterprise Application Edition in specific contexts), is...
EATTR - Extended Attributes
`EATTR` (Extended Attributes) is a data set attribute in z/OS that controls whether a data set can utilize Extended Address Volumes (EAVs) and/or be a...
EB - Exabyte
An Exabyte (EB) is a unit of digital information storage equal to one quintillion bytes, or 10^18 bytes (1,000 Petabytes). In the mainframe context, w...
EBOOST - Enhanced Boost
EBOOST, or Enhanced Boost, is a z/OS capability that allows certain general-purpose processor (CP) work to execute on specialty engines, primarily **S...
EBR - Enhanced Batch Region
EBR, or Enhanced Batch Region, is a feature of the z/OS Workload Manager (WLM) designed to dynamically manage and optimize the virtual storage region ...
EC
In the context of IBM mainframes, **EC** primarily refers to an **Engineering Change**, which is a formal modification issued by IBM for hardware or m...
ECDT - External CICS Data Table
An External CICS Data Table (ECDT) is a type of CICS data table that resides in a dedicated CICS region, known as the *data-owning region* (DOR), sepa...
Echo
In the mainframe context, "echo" primarily refers to the immediate display of characters typed by a user on a terminal screen, confirming input. It al...
ECM - Enterprise Content Management
Enterprise Content Management (ECM) in the mainframe context refers to the systematic capture, storage, management, preservation, and delivery of unst...
ECP - Extended Common Pool
The Extended Common Pool (ECP) is a specific subpool within the Extended Common Service Area (ECSA) of a z/OS system. It provides a shared storage are...
ECSA - Extended Common Service Area
ECSA (Extended Common Service Area) is a crucial area of virtual storage in z/OS, located above the 16MB line but below the 2GB bar. It contains syste...
Edge
In the context of IBM mainframe systems, the "edge" refers to the network boundaries and interfaces where the highly secure z/OS environment connects ...
Edge Server - Front-end system
In the context of IBM mainframe systems, an **Edge Server** or **Front-end system** refers to a distributed computing platform or application that act...
EDI - Electronic Data Interchange
Electronic Data Interchange (EDI) on the mainframe refers to the automated, standardized exchange of business documents (such as purchase orders, invo...
Edit
In the context of IBM z/OS, "Edit" refers to the interactive process of modifying the content of datasets, typically members within Partitioned Datase...
Edition
In the context of IBM mainframe software, an **Edition** refers to a specific, named release or major version of a product, such as an operating syste...
Editor
In the mainframe z/OS environment, an editor is a utility program primarily used to create, view, and modify text-based datasets, including source cod...
EDM - External Data Manager
EDM (External Data Manager) in DB2 for z/OS is a crucial component responsible for managing the EDM pool, an in-memory storage area for frequently acc...
EDMPOOL - External Data Manager Pool
The EDMPOOL (External Data Manager Pool) is a crucial memory area within the DB2 for z/OS `DBM1` address space, managed by the External Data Manager (...
EDP - Electronic Data Processing
EDP, or Electronic Data Processing, refers to the use of electronic computers to process commercial data, primarily for business applications. It repr...
EDTENTRY
An EDT Entry (Eligible Device Table Entry) is a data structure within the z/OS operating system that describes a specific tape device type or a pool o...
EE - Enterprise Edition
"Enterprise Edition" (EE) is a common designation used by IBM and other vendors to denote a specific version or packaging of a software product design...
EEB - Early Event Broadcasting
Early Event Broadcasting (EEB) is a facility within z/OS UNIX System Services (USS) that provides a mechanism for processes to broadcast and receive n...
EECBT - Extended Exit Control Block Table
The Extended Exit Control Block Table (EECBT) is a crucial z/OS control block that defines and manages **extended exits**. It serves as a central repo...
Effective - Currently active
In the context of IBM mainframe systems and z/OS, "effective" refers to the state where a configuration, policy, parameter, or software component is *...
Efficiency - Resource Optimization
In the mainframe context, resource optimization refers to the strategic management and tuning of system resources—such as CPU, I/O, memory, and storag...
EGRESS - Outbound traffic
Egress, in the context of z/OS and mainframe networking, refers to any network traffic or data that originates from the z/OS system and is transmitted...
EIB - Execute Interface Block
The Execute Interface Block (EIB) is a crucial CICS control block that is automatically passed to every CICS application program. It serves as the pri...
EIBRESP - EIB Response
EIBRESP (Execute Interface Block Response) is a halfword binary field within the CICS Execute Interface Block (EIB) that contains the primary response...
EIBTRNID
`EIBTRNID` (Execution Interface Block Transaction ID) is a field within the CICS `EIB` (Execution Interface Block) that contains the 4-character ident...
EIBTIME - EIB Time
`EIBTIME` is a field within the **Execute Interface Block (EIB)** that contains the elapsed time, in hundredths of a second, since the current CICS ta...
EIM - Enterprise Identity Mapping
Enterprise Identity Mapping (EIM) is an IBM technology designed to manage and map a single user identity across multiple distinct user identities on d...
EIRR - Enhanced IMS Resource Reader
EIRR (Enhanced IMS Resource Reader) is an IBM-supplied batch utility for z/OS that reads and formats various IMS control blocks and resource definitio...
Elapsed Time
Elapsed time, in the context of IBM z/OS, refers to the total "wall-clock" duration from the initiation to the completion of a job, task, transaction,...
Element
In the context of mainframe Software Configuration Management (SCM) systems (e.g., CA Endevor, IBM z/OS Change Management), an **element** represents ...
Elevate
In the context of IBM z/OS, to **elevate** refers to the act of increasing the privilege level of a program, task, or user to allow it to perform oper...
Eligible
In the z/OS environment, "eligible" describes a unit of work (such as a Task Control Block (TCB) or Service Request Block (SRB)) or a resource that is...
Elimination
In the mainframe context, "Elimination" refers to the process of removing or purging data, records, or system resources that are no longer needed, are...
ELM -
...
Embed
The act of incorporating a distinct set of instructions, data, or source code directly within a larger program, script, or data stream. In the mainfra...
Embedded SQL
Embedded SQL refers to SQL statements directly incorporated within a host programming language, such as COBOL, PL/I, C, or REXX, on IBM z/OS. It allow...
Emulation
Emulation, in the mainframe context, refers to the process of simulating the hardware and software behavior of an IBM mainframe system on a different,...
Enable
In the context of IBM z/OS and mainframe systems, "enable" refers to the process of activating a specific feature, function, component, or resource, m...
Enablement
In the context of IBM mainframe and z/OS, "enablement" refers to the process of activating, configuring, or preparing a system, software component, or...
Encapsulate
In the mainframe context, **encapsulation** refers to the practice of bundling data with the methods or procedures that operate on that data, or more ...
Enclose - Surrounding
In the context of mainframe systems, "enclosing" or "surrounding" refers to the practice of using specific characters, keywords, or structural constru...
Encode
In the mainframe context, to **encode** means to convert data, especially character data, from one representation or character set to another, or to s...
Encounter - Meeting Condition
In the mainframe context, "Encounter - Meeting Condition" refers to the detection and fulfillment of a predefined state, event, or criterion within a ...
Encrypt
Encryption is the process of transforming data (plaintext) into an unreadable, encoded format (ciphertext) using a cryptographic algorithm and a key. ...
END - Termination statement
In the mainframe context, `END` is a control statement or keyword used to mark the logical or physical termination of a program, a block of code, a da...
End User
In the mainframe context, an **End User** is the individual who directly interacts with business applications running on z/OS, typically without needi...
Endless - Continuous
In the context of IBM z/OS, "Endless - Continuous" refers to the characteristic of a system, application, or process designed for uninterrupted operat...
Endpoint - Communication terminus
In the mainframe and z/OS context, an endpoint refers to a specific network address and port combination that uniquely identifies a communication chan...
Endurance
In the mainframe context, endurance refers to the sustained ability of a system, component, or application to operate continuously and reliably over e...
Enforcement
In the mainframe context, enforcement refers to the automated or programmatic mechanisms by which z/OS and its subsystems ensure adherence to predefin...
Engine
In the context of IBM z/OS mainframes, an "engine" primarily refers to a **processor core** or a **logical processor** (CPU) responsible for executing...
Engineering Change - Modification
An Engineering Change - Modification, in the mainframe context, refers to a formal, controlled process for altering existing software components (e.g....
Enhanced
In the context of IBM mainframe systems and z/OS, "enhanced" refers to a version of a software product, feature, or capability that has been improved,...
Enlargement
In z/OS, enlargement refers to the process of increasing the allocated storage capacity for a resource, primarily datasets or the virtual storage regi...
ENQ - Enqueue resource
ENQ (Enqueue) is a fundamental z/OS serialization mechanism used to control concurrent access to shared resources, ensuring data integrity and prevent...
ENQ Contention
In z/OS, **ENQ contention** refers to a situation where multiple tasks or address spaces attempt to acquire exclusive access to the same serialized re...
ENQUEUE
ENQUEUE (often abbreviated as ENQ) is a fundamental z/OS serialization mechanism used to control access to shared resources, ensuring data integrity a...
Enterprise - Organization-wide
In the mainframe context, an "enterprise" refers to a large, complex organization (e.g., a bank, insurance company, government agency) that relies on ...
Entity
In the mainframe context, an **entity** primarily refers to a distinct, identifiable real-world object or concept about which an organization stores d...
Entry
In the context of IBM z/OS, an **entry** refers to a distinct record or descriptor within a structured collection, such as a catalog, directory, queue...
Entry Point
In IBM mainframe systems, an entry point is the specific memory address within a load module or program where execution begins when that program or ro...
Entry Sequenced - ESDS organization
An Entry Sequenced Data Set (ESDS) is a type of VSAM (Virtual Storage Access Method) file organization where records are stored in the physical order ...
Enumerate
In the z/OS environment, "enumerate" refers to the systematic process of listing, identifying, or iterating through a collection of system resources, ...
ENV - Environment
In the context of IBM z/OS and mainframe computing, an "environment" refers to the specific set of conditions, resources, and configurations under whi...
Envelope
In the mainframe context, particularly within distributed messaging and web services, an "envelope" refers to a structured container that encapsulates...
Environment Variable
In the z/OS environment, an environment variable is a dynamic named value that can affect the way running processes behave. Primarily utilized within ...
EOF - End of File
In IBM mainframe systems, particularly z/OS, the End Of File (EOF) condition signifies the logical termination point of a data set or file, indicating...
EOJ - End of Job
EOJ (End of Job) signifies the completion of all processing for a batch job submitted to the z/OS operating system. It marks the point where the Job E...
EOL - End of Line
In the mainframe context, End of Line (EOL) refers to the character or sequence of characters that signifies the termination of a line of text or a re...
EOT - End of Transmission
EOT (End of Transmission) is a control character used in mainframe communication protocols to signal the conclusion of a message, block of data, or an...
Epoch
An epoch, in computing, refers to a fixed point in time from which system time is measured. While z/OS has its own native timekeeping mechanisms, the ...
EQ - Equal
`EQ` is a symbolic comparison operator used in IBM z/OS environments, primarily within JCL, utility control statements, and programming languages, to ...
Equality
In the mainframe context, equality refers to the condition where two values, data items, or expressions are determined to be identical. This evaluatio...
Equate
In mainframe computing, "equate" refers to the process of assigning a symbolic name or alias to a value, address, register, or resource, thereby estab...
Equipment - Hardware Devices
In the mainframe context, "equipment" refers to the physical hardware components that constitute an IBM zSystem (or compatible mainframe) and its asso...
Equivalence - Logical equality
In the context of mainframe computing, **logical equality** refers to the evaluation of whether two data items, expressions, or conditions hold the sa...
ER - Entity Relationship
Entity-Relationship (ER) modeling is a conceptual data modeling technique used to represent the structure of a database by illustrating entities (data...
Erase
In the mainframe context, "erase" primarily refers to the process of deleting or removing data, datasets, or storage objects from a storage volume (DA...
ERE - Event Recording and Editing
ERE (Event Recording and Editing) is a core component of CICS (Customer Information Control System) responsible for capturing and recording significan...
EREP - Environmental Record Editing and Printing
EREP (Environmental Record Editing and Printing) is an IBM z/OS utility program used to process and format error records collected by the operating sy...
ERO - Emergency Restart Override
ERO, or Emergency Restart Override, is a CICS (Customer Information Control System) mechanism used during region startup to explicitly dictate the typ...
ERROR - Abnormal Condition
In the context of IBM mainframe systems and z/OS, an error or abnormal condition refers to any unexpected event, deviation from normal program executi...
Error Code
An error code in the mainframe/z/OS context is a numeric or alphanumeric value that indicates a specific problem, abnormal condition, or exceptional e...
Error Handler - Recovery Routine
An error handler, specifically a recovery routine in the mainframe z/OS context, is a specialized program component designed to gain control when an a...
Error Log
An error log in the mainframe context is a persistent record of error conditions, abnormal terminations (abends), warnings, or significant events gene...
Error Message
In the z/OS environment, an **error message** is a textual notification generated by the operating system, a utility, or an application program to ind...
Error Recovery
Error recovery in the mainframe context refers to the comprehensive set of mechanisms and procedures designed to detect, diagnose, and resolve failure...
Escalate
In the context of IBM z/OS and mainframe systems, "escalate" primarily refers to the act of increasing the **dispatching priority** of a workload, tas...
ESCON Director
An ESCON Director is a specialized fiber optic switching device used in IBM mainframe environments to provide high-speed, any-to-any connectivity betw...
ESD - External Symbol Dictionary
The External Symbol Dictionary (ESD) is a crucial component within an `object module` or `load module` on z/OS. It serves as a directory that lists al...
ESDS - Entry Sequenced Data Set
An Entry Sequenced Data Set (ESDS) is a type of VSAM (Virtual Storage Access Method) data set where records are stored in the physical order they are ...
ESM - External Security Manager
An External Security Manager (ESM) is a mainframe software product, such as IBM's `RACF` (Resource Access Control Facility), Broadcom's `ACF2`, or Bro...
ESOTERIC
In z/OS, an **ESOTERIC** device group name is a user-defined symbolic name that represents a collection of physically similar or functionally equivale...
ESP - Enhanced System Productivity
ESP (Enhanced System Productivity) is a leading workload automation and job scheduling product for IBM z/OS environments, developed by Broadcom (forme...
ESS - Enterprise Storage Server
An Enterprise Storage Server (ESS), often synonymous with IBM's DS8000 series, is a high-performance, highly available disk storage system designed to...
Establish
In the context of IBM z/OS and enterprise computing, to **establish** typically refers to the process of initiating and setting up a logical connectio...
Estimate - Approximation
In the mainframe context, an estimate or approximation refers to a reasoned judgment or calculation of a future value, quantity, or duration, often ma...
ESV - External Security Verification
ESV, or External Security Verification, is the process by which an application or system component on z/OS delegates the authorization check for a use...
ET - Event Trace
Event Trace (ET) is a diagnostic and performance monitoring facility in IBM z/OS that records specific events occurring within the operating system, i...
Ethernet - Network protocol
Ethernet is a widely adopted family of computer networking technologies that define the physical and data link layers of the OSI model. In the context...
ETL - Extract Transform Load
ETL (Extract, Transform, Load) is a three-phase process used to collect data from various sources, transform it into a usable format, and load it into...
ETOM - Enhanced Telecommunications Operations Map
ETOM, or Enhanced Telecommunications Operations Map, is a specialized component within IBM's `NetView` product on `z/OS` designed to automate the moni...
ETO - Enhanced Terminal Option
Enhanced Terminal Option (ETO) is a CICS feature that provides dynamic definition of CICS terminals and Logical Units (LUs) at sign-on or connection t...
ETSO - Extended TSO
ETSO, or Extended TSO, refers to the enhanced, full-screen, menu-driven interactive environment provided to z/OS users. It significantly extends the c...
EBCDIC
The character encoding scheme used by IBM mainframes to represent text characters, different from ASCII used in most other computing systems. EBCDIC u...
Enclave
A collection of related work that executes under a single service class for performance management purposes. Enclaves enable Workload Manager (WLM) to...
Enterprise COBOL
IBM's modern COBOL compiler for z/OS, supporting contemporary features like object-oriented programming, XML processing, and Java integration while ma...
ESDS
A VSAM dataset where records are stored in the order they are written, similar to sequential files but with VSAM's advanced features. ESDS provides se...
EBCDIC - Extended Binary Coded Decimal Interchange Code
EBCDIC (Extended Binary Coded Decimal Interchange Code) is an 8-bit character encoding used primarily on IBM mainframe operating systems like z/OS. It...
Edit Macro
An `ISPF` Edit macro is a user-defined or system-provided program that automates a sequence of `ISPF` Edit commands or `TSO` commands to perform compl...
Emulator
An emulator, in the mainframe context, is a software program that allows a non-mainframe system (typically a PC or server) to mimic the behavior of a ...
Encryption
Encryption is the process of transforming data into an unreadable, encoded format (ciphertext) to prevent unauthorized access. In the z/OS environment...
ENF - Event Notification Facility
ENF (Event Notification Facility) is a core component of IBM's z/OS operating system, integrated with Global Resource Serialization (GRS), that provid...
ENQ - Enqueue resource request
ENQ (Enqueue) is a fundamental z/OS serialization mechanism used to control access to shared resources, preventing concurrent updates or conflicting o...
Environment
In a mainframe context, an "environment" refers to the specific set of system settings, configurations, resources, and software components that define...
EOD - End of Data
EOD, or End of Data, is a condition signaled by the operating system or access method to an application program when all records in a dataset or file ...
EOT - End of Tape
EOT, or End of Tape, is a physical or logical indicator on a magnetic tape volume that signifies the approaching or actual end of the usable recording...
EOV - End of Volume
EOV, or End of Volume, is a condition in z/OS that signifies a data set has reached the physical or logical capacity limit of a single storage volume,...
EREP - Environmental Recording Editing and Printing
EREP (Environmental Recording Editing and Printing) is an IBM z/OS utility program designed to process and report on hardware error records collected ...
ESCON - Enterprise Systems Connection
ESCON (Enterprise Systems Connection) is a high-speed, serial, full-duplex, fiber optic channel architecture developed by IBM for connecting mainframe...
ESO - Exclusive System Owner
ESO (Exclusive System Owner) is a resource serialization mechanism in z/OS that ensures only one system within a **sysplex** can hold exclusive contro...
ESP - External Security Package
An External Security Package (ESP) is a generic term for a security software product used on IBM z/OS mainframe systems to provide comprehensive acces...
Esoteric Name - Symbolic device group name
An esoteric name in z/OS is a symbolic name assigned to a group of similar I/O devices, allowing a job step to request any available device from that ...
ETR - External Time Reference
The External Time Reference (ETR) is a hardware component used in IBM mainframe environments to synchronize the Time-of-Day (TOD) clocks of multiple z...
Event
In the context of z/OS, an **event** is a significant occurrence, change in state, or condition within the system or an application that requires atte...
EXEC Statement
The `EXEC` (Execute) statement is a fundamental Job Control Language (JCL) statement in z/OS that marks the beginning of a job step. Its primary purpo...
EXECUTE
In the mainframe context, **execution** refers to the process by which the z/OS operating system loads a compiled program (a `load module`) into an a...
Effective
In the context of IBM mainframe systems, "effective" or "currently active" describes the state where a specific configuration, parameter, resource, or...
EGRESS
In the context of IBM z/OS and mainframe networking, egress refers to the flow of data *out* of the z/OS system, a specific logical partition (LPAR), ...
EIBTRNID - EIB Transaction ID
`EIBTRNID` is a field within the CICS (Customer Information Control System) Execute Interface Block (EIB) that contains the 4-character identifier of ...
EITG - Enterprise Integration Technologies Gateway
The Enterprise Integration Technologies Gateway (EITG) is a conceptual or architectural component, often implemented using various IBM technologies on...
Elevate - Increase privilege level
In the z/OS environment, "elevating privilege" refers to the process by which a program, task, or user gains increased authorization to access protect...
Elimination - Removing
In the context of IBM mainframe systems and z/OS, "Elimination - Removing" refers to the controlled process of permanently or temporarily deactivating...
ELM - Extended Link Module
An Extended Link Module (ELM) is a specialized program module used by CICS (Customer Information Control System) to facilitate the linking of a progra...
Embedded Statements
Embedded statements refer to database manipulation language (DML) or data definition language (DDL) statements, such as SQL for DB2 or DL/I calls for ...
Compliance Enforcement
In the mainframe context, compliance enforcement refers to the systematic application and monitoring of rules, policies, and standards to ensure that ...
Engine - Processing component
An engine, in the context of IBM zSystems, refers to a core processing component that provides computational power. It typically denotes a Central Pro...
Enlarge
In the context of z/OS, "enlarge" primarily refers to increasing the allocated storage space for a dataset on direct access storage devices (DASD) or ...
Enterprise
...
Entity Bean
An **Entity Bean** is a component within the **Java EE (Java Platform, Enterprise Edition)** architecture designed to represent persistent data stored...
Enumerate - Listing items
In the context of z/OS, "enumerate" refers to the act of systematically listing, detailing, or cataloging items, resources, or conditions within the m...
ETC - Et Cetera
"Et Cetera" (often abbreviated as ETC or etc.) is a Latin phrase meaning "and other things" or "and so on." In the context of mainframe systems, it is...
Ethernet
Ethernet, in the context of IBM mainframe systems and z/OS, refers to the widely adopted family of computer networking technologies that provide the p...
ETW - Event Tracing for Windows
Event Tracing for Windows (ETW) is a high-performance, general-purpose, block-based event tracing facility provided by the Microsoft Windows operating...
EVALUATE
In the context of mainframe programming, particularly COBOL, `EVALUATE` is a powerful multi-way conditional statement used to select one of several po...
Event Control Block - ECB synchronization
An Event Control Block (ECB) is a 16-byte control block in z/OS used to represent the occurrence or completion of an event. ECB synchronization refers...
Event Driven
In the context of IBM mainframe systems and z/OS, "event-driven" describes a system or program design paradigm where the flow of execution is determin...
Evict
In the context of IBM z/OS and mainframe systems, `evict` refers to the process of removing data, code, or control blocks from a specific storage area...
EWA - Enhanced Work Area
EWA (Enhanced Work Area) is a CICS-specific data area primarily used by COBOL programs to pass parameters between linked or transferred programs. It i...
Exact - Precise match
An exact or precise match refers to a comparison operation where two values, strings, or data elements must be identical in content, case, and length ...
Examine - Inspecting
`EXAMINE` and `INSPECT` are COBOL verbs used to analyze and manipulate character strings within data items. `INSPECT` is the modern, more powerful suc...
Exception
In the mainframe and z/OS context, an **exception** refers to an unusual or erroneous condition that occurs during the execution of a program or syste...
Exception Handling
Exception handling in the mainframe context refers to the programmatic mechanisms used to detect, intercept, and respond to abnormal conditions or err...
Exclamation - Alert symbol
The exclamation mark (`!`) is a special character that, within the IBM mainframe and z/OS environment, is primarily used by applications, scripts, and...
Exclude
In the context of mainframe data processing and utilities, "exclude" refers to the action of filtering out or removing specific records, data elements...
Exclusive Access
In the context of IBM z/OS, **Exclusive Access** refers to a state where a specific system resource (such as a dataset, a database record, or a contro...
Exclusive Lock
An exclusive lock is a concurrency control mechanism that grants a single task or transaction sole access to a specific resource, preventing any other...
EXCPVR - Execute Channel Program Virtual
EXCPVR (Execute Channel Program Virtual) is a low-level z/OS macro instruction that allows an authorized program to perform direct I/O operations to a...
Executable
In the context of IBM z/OS, an executable refers to a program in a machine-readable format, typically a **load module** or **program object**, that is...
Execute Channel Program - EXCP I/O
Execute Channel Program (EXCP) is a low-level I/O access method on IBM z/OS and its predecessors that allows a program to directly control I/O operati...
Execution
In the mainframe and z/OS context, **execution** refers to the process of a program, job, or transaction being loaded into memory and run by the centr...
Executive - Control program
In the context of IBM mainframes and z/OS, an "Executive" or "Control Program" refers to the core component of the operating system responsible for ma...
Exempt
In the context of z/OS, "exempt" refers to a specific entity (such as a user, resource, or process) being explicitly **excluded from a general rule, p...
Exhaust
In the context of mainframe systems, "exhaust" refers to the complete consumption or depletion of a finite system resource, such as memory, CPU cycles...
EXHST - Exhaust
In mainframe computing, "exhaust" (often abbreviated as `EXHST` in custom contexts) refers to the complete processing or consumption of a finite data ...
Exist
In the context of z/OS, "exist" refers to the state of an entity (such as a dataset, program, job, task, or system resource) being present, identifiab...
Exit
In the mainframe context, an "exit" refers to a predefined point within an IBM operating system (like z/OS), a subsystem (such as CICS, DB2, or IMS), ...
Exit Routine
An exit routine is a user-written program or module that gains control at specific, predefined points within an IBM z/OS operating system component, s...
Expand - Increasing size
In the mainframe context, "expand" primarily refers to increasing the allocated size or capacity of a resource, such as a dataset, a storage area, or ...
Expansion
In the context of IBM z/OS, "expansion" primarily refers to **data set expansion**, the process by which a data set automatically or manually acquires...
Expectation
In the mainframe context, "expectation" refers to the act of a program, system component, or operator waiting for a specific event, condition, or inpu...
Expedite
In the mainframe context, "expedite" refers to the act of assigning a higher priority to a specific job, task, transaction, or process to ensure its f...
Expiration
In the context of IBM z/OS, **expiration** refers to the predefined date or period after which a resource, most commonly a data set, is no longer cons...
Expiration Check
An expiration check in the mainframe context is the process of verifying whether a resource, data element, or security credential is still valid for u...
Explicit
In the context of mainframe and z/OS, "explicit" refers to something that is directly and unambiguously stated or defined by a programmer or system ad...
Explicit Lock - Requested by program
An explicit lock, requested directly by an application program, is a mechanism used to serialize access to a shared resource, such as a database table...
Explode
In the context of mainframe systems, "exploding" refers to the process of decompressing or expanding data that was previously compressed. This operati...
Exploit
In the context of mainframe and z/OS, "exploit" refers to the act of strategically leveraging or making full, effective use of a system's inherent fea...
Exponent - Power indicator
In the context of IBM mainframe systems, an **exponent** is a component of a floating-point number that indicates the power to which the base (typical...
Export
In the mainframe and z/OS context, "export" refers to the process of extracting data from a z/OS system or its components (e.g., DB2, IMS, VSAM, seque...
Exposure - Vulnerability
In the context of IBM mainframe systems, a **vulnerability** refers to a weakness or flaw in the z/OS operating system, installed software, custom app...
Express - Fast or direct
In the context of IBM mainframe systems and z/OS, "Express" or "Fast/Direct" refers to specialized architectural components, processing modes, or data...
Expression
In the context of IBM mainframe systems, an expression is a combination of operands (such as variables, literals, or constants) and operators (arithme...
EXSM - External Security Module
An External Security Module (EXSM) is a specialized program module on z/OS that provides an interface between an application or system component and a...
Extend
Dataset extension is the process of increasing the allocated storage space for an existing dataset on an IBM z/OS system. This operation allows a data...
Extended
In the context of IBM mainframe systems and z/OS, "Extended" typically refers to an enhancement or expansion of a system resource, capability, or arch...
Extended Architecture - Larger addressing
Extended Architecture (XA) refers to a significant evolution in IBM mainframe architecture that introduced 31-bit addressing, expanding the virtual st...
Extended Common Storage
Extended Common Storage (ECS) is a crucial area of z/OS virtual storage located above the 16MB line (24-bit address boundary). It serves as a shared m...
Extended Format
Extended Format refers to a data set organization type in z/OS that allows for significantly larger data sets and enhanced capabilities compared to tr...
Extended Recovery
In the mainframe context, **Extended Recovery** refers to advanced mechanisms and protocols, primarily within subsystems like CICS, IMS, or DB2, that ...
Extensible
In the context of IBM mainframe systems and z/OS, "extensible" refers to the capability of a system, application, or component to be enhanced, modifie...
Extent - Allocated space
An extent in the mainframe context refers to a contiguous block of physical storage space on a Direct Access Storage Device (DASD) that is allocated t...
Extent Separation - Spreading allocations
Extent separation, often referred to as spreading allocations, is a technique used in z/OS to improve I/O performance and availability for multi-volum...
External
In mainframe computing, "external" generally refers to resources, components, or code that reside outside the immediate scope or address space of a sp...
External Data
In the context of IBM mainframe systems and z/OS, "external data" refers to any data that originates from sources outside the immediate processing sco...
External Interrupt - Hardware signal
An external interrupt is a hardware-generated signal that causes the CPU to stop its current execution and transfer control to a specific interrupt ha...
External Reference
An **external reference** in the mainframe context refers to a symbolic name (such as a program name, subroutine entry point, or data item) that is re...
External Security Manager
An External Security Manager (ESM) is a software product on z/OS that provides centralized control over system resources, user authentication, and aut...
External Writer
An External Writer is a specialized program or started task in z/OS that processes output from the Job Entry Subsystem (JES) spool. It acts as an outp...
Extract
In the mainframe context, **Extract** refers to the process of selecting and copying a subset of data from a larger data source, such as a sequential ...
Extraction
"Extraction" in the mainframe context refers to the process of selectively retrieving specific data records or fields from a larger dataset, file (e.g...
F
FTP
Standard protocol for transferring files between systems over TCP/IP networks, supported on mainframes for data exchange with distributed platforms. F...
FTPS
Secure version of FTP using SSL/TLS encryption for protected file transfers, providing confidentiality and integrity for data in transit between mainf...
Facility
In the context of IBM z/OS and mainframe systems, a **facility** refers to a distinct, often named, component, service, or set of integrated functions...
Factory
In the context of mainframe application development, particularly for object-oriented languages like Java or C++ running on z/OS, a Factory is a desig...
Factory Default
While the specific term "factory default" is not standard mainframe jargon, it conceptually refers to the initial, vendor-supplied configuration and s...
Fail
In the context of IBM mainframe systems, to **fail** refers to the abnormal termination or inability of a program, job, transaction, or system compone...
Failback - Returning to primary
Failback is the process of returning IT operations, applications, and data processing to the original, primary system or site after a failover event. ...
Failover
Failover is a critical process in mainframe environments that involves automatically or manually switching to a redundant or standby system, component...
Failsafe
In the context of IBM mainframe systems and z/OS, "failsafe" refers to the design and implementation of mechanisms that ensure a system, application, ...
Failure
In the mainframe and z/OS context, a **failure** refers to the unsuccessful completion of a program, job, transaction, or system component operation. ...
Fair Share
In the context of IBM z/OS, **Fair Share** refers to a Workload Manager (WLM) principle that ensures equitable distribution of system resources, prima...
FALSE
In mainframe programming, `FALSE` represents the logical negative outcome of a condition or a binary state indicating "no," "off," or "not true." It i...
Family
In mainframe computing, a "family" refers to a group of related hardware, software products, or data entities that share a common lineage, architectur...
Fan-In
In mainframe computing, "fan-in" refers to the number of other modules, programs, or components that directly call, invoke, or depend on a single spec...
Fan-Out
In the context of IBM mainframe systems and z/OS, **fan-out** refers to a design pattern or operational characteristic where a single source distribut...
FAP - Fortran Assembly Program
FAP, or Fortran Assembly Program, was an assembly language specifically designed for the IBM 7090 and 7094 series mainframe computers in the early 196...
FAQ - Frequently Asked Questions
An FAQ (Frequently Asked Questions) is a collection of common questions and their corresponding answers, compiled to provide quick solutions and infor...
Fast Path
**Fast Path** is an optional, high-performance component of **IMS DB/DC** designed to handle extremely high transaction volumes with very low response...
FAT - File Allocation Table
The File Allocation Table (FAT) is a legacy file system architecture primarily associated with DOS, early versions of Microsoft Windows, and various e...
Fatal Error
A fatal error in the mainframe context refers to an unrecoverable condition that causes the immediate and abnormal termination of a program, job step,...
Fault
In mainframe systems, a fault refers to an underlying defect or imperfection within hardware, software, or configuration that has the potential to cau...
Fault Tolerance
Fault tolerance in the z/OS environment refers to the ability of a system or application to continue operating correctly and without interruption desp...
FBA - Fixed Block Architecture
Fixed Block Architecture (FBA) is a storage device architecture where data is organized and accessed in fixed-size blocks, typically 512 bytes, each i...
FBSET - Fixed Block Set
FBSET (Fixed Block Set) refers to a record format, specified as `RECFM=FBS`, primarily used for sequential data sets on magnetic tape in z/OS. In this...
FC - Function Complete
In the context of mainframe software development and...
FCA - Fibre Channel Adapter
An FCA (Fibre Channel Adapter) is a hardware component within an IBM mainframe that provides high-speed, serial I/O connectivity to Fibre Channel Stor...
FCB - File Control Block / Forms Control Buffer
FCB is an acronym with two distinct meanings in the mainframe and z/OS environment: **File Control Block** and **Forms Control Buffer**. A **File Cont...
FCQRDATA - Fast Communication Query Data
FCQRDATA (Fast Communication Query Data) is an internal VTAM (Virtual Telecommunications Access Method) data area on z/OS designed to provide quick ac...
FD - File Descriptor
In COBOL, `FD` stands for File Description. It is a declarative paragraph within the `FILE SECTION` of the `DATA DIVISION` that defines the characteri...
FDR - Fast Dump Restore
FDR (Fast Dump Restore) is a leading third-party software product from Innovation Data Processing, widely used on IBM z/OS systems for high-speed back...
FDSA - Fixed Direct Storage Access
FDSA (Fixed Direct Storage Access) refers to a type of data set organization on IBM z/OS where records are stored and retrieved based on their fixed l...
Feature
In the context of IBM mainframe systems and z/OS, a **feature** refers to a distinct capability, function, or enhancement provided by an operating sys...
Feature Code
A Feature Code, in the IBM mainframe context, is an alphanumeric identifier used to specify a particular component, option, or capability of an IBM ha...
Federate
To `federate` in the mainframe context typically refers to the process of integrating disparate data sources, applications, or services, often across ...
Federation
In the z/OS and enterprise computing context, **data federation** refers to the technology and process of integrating data from multiple, disparate da...
Feedback - Response Information
In the mainframe context, "Feedback - Response Information" refers to the various codes, messages, and diagnostic data generated by z/OS, batch jobs, ...
Feeder
In the context of IBM z/OS, a **feeder** refers to a program, job step, or process specifically designed to prepare and supply input data to a subsequ...
Fetch
In mainframe computing, "Fetch" primarily refers to two distinct but related concepts: the dynamic loading of an executable program or module into vir...
FFS
In the context of z/OS, while "FFS" is not a standard acronym for a specific component, it generally refers to a **File System**, which is a method an...
FFT - Fast Fourier Transform
The Fast Fourier Transform (FFT) is an efficient algorithm used to compute the Discrete Fourier Transform (DFT) and its inverse. In the mainframe and ...
Fiber Optic Cable
A fiber optic cable is a networking cable that contains one or more optical fibers, which are thin strands of glass or plastic used to transmit data a...
Fiber Channel
Fiber Channel is a high-speed networking technology primarily used in mainframe environments to connect z/OS systems to Storage Area Networks (SANs) a...
Fidelity
In the mainframe context, **fidelity** refers to the degree of exactness or accuracy with which data, processes, or system states are reproduced, main...
Field - Data element
In mainframe computing, a **field** is the smallest meaningful unit of data within a record, file, or database. It represents a specific piece of info...
FIFO - First In First Out
FIFO (First In First Out) is a fundamental principle in computing and data structures where the first element added to a queue or buffer is the first ...
File
In the context of IBM z/OS, a **file** is commonly referred to as a **dataset**, representing a named collection of related data records stored on a d...
File Allocation - Space Assignment
File allocation, in the z/OS context, refers to the process of reserving and assigning specific storage space on a Direct Access Storage Device (DASD)...
File Control
File Control is a core component of CICS (Customer Information Control System) that provides application programs with a high-level interface to acces...
File Handle
In the context of z/OS, a **file handle** (or dataset handle) is a system-assigned identifier that represents an open dataset or file within a program...
File Sharing - Multiple access
In the z/OS environment, file sharing with multiple access refers to the capability for multiple jobs, users, or address spaces to concurrently read f...
File Transfer
In the mainframe context, **File Transfer** refers to the process of moving data, typically in the form of datasets or dataset members, between an IBM...
Fill - Populating with data
In the context of mainframe computing, "filling" or "populating with data" refers to the process of initializing data structures, variables, files, or...
Filter
In the context of IBM z/OS, a filter refers to the process or mechanism of selecting a specific subset of data, records, messages, or members from a l...
Final - Last in sequence
In the context of IBM mainframe z/OS batch processing and application programming (e.g., COBOL), "Final - Last in sequence" refers to a condition or i...
Finalization - Cleanup process
In the mainframe context, **finalization** or **cleanup** refers to the systematic process of releasing system resources, closing files, deallocating ...
Finalize - Completing
In the mainframe context, "finalizing" or "completing" refers to the process by which a task, job, transaction, or resource operation reaches its conc...
Finance - Financial Processing
Financial processing on the mainframe refers to the execution, management, and recording of monetary transactions, accounting operations, and financia...
Find
In the context of z/OS, `Find` refers to the operation of locating specific character strings, patterns, or hexadecimal values within datasets, member...
Fine Grained
In the mainframe context, "fine-grained" refers to a high level of detail, specificity, or granularity in control, access, or management of resources,...
Fingerprint
In the z/OS context, a "fingerprint" refers to a unique, fixed-size cryptographic hash value generated from a block of data, a file, or a program. Its...
Finite - Limited
In the context of IBM mainframe systems and z/OS, "finite" or "limited" refers to the inherent, bounded nature of all system resources, capacities, an...
Firewall
A firewall, in the context of mainframe security, is a network security system that monitors and controls incoming and outgoing network traffic based ...
Firmware
Firmware is a specialized type of embedded software that provides low-level control for a device's specific hardware. In the mainframe context, it res...
First Failure
In the context of mainframe systems, "first failure" refers to the initial error, anomaly, or event that triggers a chain of subsequent problems, syst...
First Level Interrupt Handler - FLIH processing
A First Level Interrupt Handler (FLIH) is a highly optimized, low-level routine in z/OS that gains control immediately after a hardware interrupt occu...
First Pass - Initial processing
In the context of compilers (like COBOL) or assemblers (like HLASM) on z/OS, the "first pass" refers to the initial scan of the source code. Its prima...
FIST - Federation for Information Systems Technology
The acronym `FIST` (Federation for Information Systems Technology) is **not a standard or commonly recognized term, technology, or organization within...
Fixed - Not variable
In mainframe computing, particularly within z/OS, 'fixed' refers to an attribute where the size, length, or capacity of a data element, record, or sto...
Fixed Format
In the context of IBM z/OS, "Fixed Format" primarily refers to data records or source code where each record or line has a predefined, unchanging leng...
Fixed Length
In mainframe computing, **Fixed Length** refers to data elements, records, or files where every instance occupies a predetermined, constant amount of ...
Fixed Point - Integer arithmetic
Fixed-point integer arithmetic on the mainframe refers to computations performed using integer data types where the decimal point is *implicitly* fixe...
Flag - Indicator or marker
In the mainframe and z/OS context, a flag is a bit, byte, or a small field used as a binary or multi-state indicator to signal a specific condition, s...
Flash Storage
Flash storage, often implemented as Solid State Drives (SSDs) within enterprise...
FlashCopy - Fast disk copy
FlashCopy is a hardware-assisted feature of IBM storage systems, primarily the DS8000 series, that creates an instantaneous, point-in-time copy of a s...
Flat File
A flat file on z/OS is a simple, non-relational data set where records are typically stored in a sequential manner without complex internal structures...
Flatness
In the mainframe context, "flatness" primarily refers to the absence of complex, multi-level hierarchical structures in data organization or processin...
Flavor
In the context of mainframe computing, "flavor" is a colloquial and informal term used to refer to a specific variant, version, configuration, or spec...
Flexibility and Adaptability
In the mainframe context, **Flexibility and Adaptability** refer to the inherent capacity of z/OS systems, applications, and operational practices to ...
Flip - Reversing state
In mainframe computing, "flipping" refers to the action of reversing the state of a binary value, flag, bit, or condition from one opposite to another...
Float - Floating Point Number
A floating-point number is a numerical data type used to represent real numbers (numbers with fractional parts) in a computer system. On IBM mainframe...
Floating Point - Decimal arithmetic
Decimal floating-point (DFP) arithmetic is a method of representing and performing calculations on real numbers (numbers with fractional parts) using ...
Floppy - Removable disk
A floppy disk is a type of magnetic data storage device composed of a thin and flexible magnetic storage...
Flow
In the context of IBM mainframe systems, "flow" refers to the sequential execution of instructions within a program or job, the progression of a trans...
Flow Control - Regulating transmission
In the context of IBM mainframe and z/OS, flow control refers to the mechanisms used in data communication to manage the rate of data transmission bet...
Flowchart - Process diagram
A flowchart is a graphical representation of a process, algorithm, or workflow. In the mainframe context, it visually depicts the sequence of operatio...
Fluctuation/Variation
In the context of IBM mainframe systems and z/OS, "Fluctuation/Variation" refers to the observable changes or deviations in system metrics, resource u...
Flush
In the mainframe and z/OS context, "flush" refers to the process of writing buffered data from main memory (storage buffers) to a persistent storage d...
FMH - Function Management Header
A Function Management Header (FMH) is a control block used within IBM's Systems Network Architecture (SNA) to carry specific control information betwe...
FMT - Format
In the mainframe and z/OS context, "format" refers to the precise structure, arrangement, and characteristics of data, records, files, messages, or sc...
Fold - Case conversion
In mainframe computing, case conversion, often referred to as "folding," is the process of transforming characters between their uppercase and lowerca...
Font
In the mainframe context, a **font** refers to a complete set of characters (letters, numbers, symbols) of a specific design, style, and size, primari...
Footprint
In the mainframe context, "footprint" refers to the total amount of system resources (e.g., memory, disk space, CPU cycles, I/O operations) consumed b...
FOR - Iteration construct
An iteration construct, often conceptually referred to as a "FOR loop," is a control flow statement used in programming languages to repeatedly execut...
FORCE
In the context of IBM z/OS, "force" refers to an administrative action taken to override normal system procedures or immediately terminate a hung, unr...
Forecast - Prediction
In the mainframe context, forecasting and prediction refer to the process of analyzing historical operational data to anticipate future trends in reso...
Foreground - Interactive priority
In the context of z/OS, "Foreground - Interactive priority" refers to the execution of tasks or applications that directly interact with a user, provi...
Foreign Key
A `FOREIGN KEY` is a column or a set of columns in a DB2 for z/OS table that refers to the `PRIMARY KEY` (or a `UNIQUE KEY`) in the same table or anot...
Forensics
Mainframe forensics, in the context of IBM z/OS, is the systematic process of collecting, preserving, analyzing, and presenting digital evidence relat...
Fork
In the context of z/OS, `fork()` refers to a POSIX-compliant system call available within z/OS UNIX System Services (z/OS UNIX) that creates a new pro...
Data Entry Screen
A Data Entry Screen, often referred to as a "form" in modern computing, is a character-based interactive display presented on a 3270 terminal or emula...
Format
In the mainframe and z/OS context, "format" refers to the predefined structure, arrangement, or layout of data, records, files, screens, or instructio...
Forms - Printed output
In the context of IBM mainframes and z/OS, "forms" refers to both the physical pre-printed paper stock used for output (e.g., invoices, checks) and th...
Formula - Calculation expression
In the context of mainframe computing, a calculation expression (often referred to as a formula) is a sequence of operands and operators that evaluate...
FORTRAN
FORTRAN (Formula Translation) is one of the oldest high-level programming languages, originally developed by IBM in the 1950s for scientific and engin...
Forward Recovery
Forward recovery, also known as roll-forward recovery, is a data recovery technique used in mainframe environments to restore a database or dataset to...
z/OS Operating System
z/OS is IBM's flagship mainframe operating system, serving as the foundational software layer for enterprise-grade workloads on IBM Z hardware. It pro...
FP - Floating Point
Floating Point (FP) is a method for representing real numbers (numbers with fractional parts) in a computer system, allowing for a wide dynamic range ...
FPU - Floating Point Unit
A Floating Point Unit (FPU) is a specialized hardware component within an IBM mainframe's processor designed to perform arithmetic operations on float...
Fragment
In mainframe computing, a fragment typically refers to a small, unusable or inefficiently used piece of storage or data space. This condition, known a...
Fragmentation
Fragmentation, in the context of IBM z/OS, refers to the inefficient utilization of storage space (either disk or virtual memory) due to the scatterin...
Frame
A **frame** in the context of z/OS networking refers to a data unit at the Data Link Layer (Layer 2) of the OSI model. It encapsulates higher-layer ne...
Frame Relay
Frame Relay is a high-performance, connection-oriented packet-switching wide area network (WAN) protocol that operates at the data link layer (Layer 2...
Framework
In the context of IBM z/OS, a framework refers to a collection of reusable components, standardized processes, and architectural guidelines that provi...
Free Storage and Free Space
In the context of z/OS, "Free" primarily refers to unallocated or unused resources that are available for immediate use. This commonly applies to **Fr...
Free Form - Unstructured
In the mainframe context, "free form" or "unstructured" typically refers to data or input that does not conform to a predefined, fixed-column format o...
Free Space
In the mainframe context, "free space" refers to unallocated or unused storage within a data set, volume, or database structure (such as VSAM clusters...
Freelist - Available items list
A freelist is a data structure, typically a linked list, that maintains a collection of available (free) blocks of memory or other system resources th...
Freemain
`Freemain` is a z/OS system service used by programs to release dynamically acquired virtual storage back to the operating system or a specific storag...
Frequency
In the context of IBM z/OS and mainframe systems, **frequency** refers to the rate at which specific events, transactions, or operations occur within ...
Front End
In the mainframe context, a "Front End" refers to the user interface layer that provides a means for users to interact with and access applications, d...
Front-End Processor (FEP) Communications
A Front-End Processor (FEP), typically an IBM `37xx` Communication Controller, is a specialized hardware device that offloads communication tasks from...
FS - File System
In the mainframe context, a File System (FS) refers to the method and structure used by z/OS to organize, store, retrieve, and manage data. While trad...
FSR - Function Status Return
In the context of IBM mainframe systems and z/OS, FSR typically refers to a **Function Status Return** code or register used by various system compone...
FSYNC - File Synchronization
`fsync` is a POSIX system call available within z/OS UNIX System Services (USS) that forces all modified in-memory data and metadata (e.g., file size,...
FTP - File Transfer Protocol
File Transfer Protocol (FTP) is a standard network protocol used to transfer computer files from a server to a client on a computer network. In the z/...
Full
In the context of mainframe systems, "Full" describes a state where a storage resource (such as a dataset, DASD volume, or buffer) or a processing que...
Full Backup
A full backup in the z/OS environment involves creating a complete copy of all selected data, whether it's an entire volume, a set of datasets, or a d...
Full Duplex
Full Duplex is a communication mode that allows simultaneous, two-way data transmission between two connected devices. In the mainframe context, this ...
Full Screen
In the context of IBM mainframe systems, "Full Screen" refers to an interactive display mode where an entire screen of a 3270-type terminal (or its em...
Fullword
A fullword is a standard unit of data storage on IBM mainframe systems, consisting of four contiguous bytes (32 bits). It is primarily used to store s...
Function
In mainframe programming, particularly within languages like COBOL, PL/I, and C/C++, a **function** is a self-contained, reusable block of code design...
Function Code - Operation identifier
In the mainframe context, a Function Code or Operation Identifier is a specific value (often numeric or an alphanumeric mnemonic) that designates the ...
Function Key
In the mainframe context, a Function Key (often referred to as a Program Function key or PF key, or Program Attention key or PA key) is a special key ...
Function Shipping
Function Shipping is a CICS intercommunication facility that allows an application program in one CICS region to access resources (such as files, temp...
Functional - Operational
This distinction refers to the two primary dimensions along which a mainframe system, application, or component is evaluated and managed: its intended...
Functionality - Capabilities
In the context of IBM mainframe systems, z/OS, and enterprise computing, "functionality" or "capabilities" refers to the complete set of operations, f...
Funnel - Combining multiple sources
In the mainframe context, "funneling" refers to the process of consolidating data from multiple disparate input sources into a single, unified output ...
FW - Fullword
A **Fullword** (FW) is a fundamental fixed-length data unit in IBM mainframe architecture, occupying 4 bytes (32 bits) of contiguous storage. It is pr...
FX - Fixed or Effects
In the context of IBM mainframe systems and z/OS, 'FX' primarily refers to **Fixed**, denoting a predetermined, unvarying size or structure for data e...
G
GDG
A group of related sequential datasets organized chronologically, with each dataset called a generation. GDGs are useful for maintaining historical ve...
GDDM
IBM software for creating graphical presentations, charts, and business graphics in mainframe applications. GDDM provides graphics primitives and high...
GEAC
Enterprise resource planning (ERP) software commonly run on mainframe systems, particularly in government and utilities sectors. GEAC provides integra...
Green Screen
Colloquial term for traditional mainframe terminal interfaces, named after the green monochrome displays of early 3270 terminals. Refers to character-...
GSAM
An IMS access method for processing sequential datasets within IMS applications, providing integration between IMS transactions/programs and standard ...
GAM - Global Access Method
GAM (Global Access Method) is an IBM mainframe facility that provides shared access to VSAM (Virtual Storage Access Method) data sets across multiple ...
Gang Scheduling - Group Scheduling
In the context of z/OS, "Gang Scheduling" or "Group Scheduling" refers to the operating system's capability, primarily through the Workload Manager (W...
GAP - Generic Alert Processor
GAP (Generic Alert Processor) is an IBM NetView component that processes unsolicited messages and events from z/OS and its subsystems, transforming th...
Garbage Collection
In the context of z/OS, Garbage Collection (GC) is an automatic memory management process primarily used by Java Virtual Machines (JVMs) to reclaim me...
Gate - Control Point
A "gate" or "control point" in the mainframe context refers to a specific juncture within a system, application, or process where conditions are evalu...
Gateway
A gateway, in the z/OS context, is a specialized network device or software component that acts as an interface between different networks or protocol...
GB - Gigabyte
A Gigabyte (GB) is a standard unit of digital information storage, representing 1,024 megabytes (MB) or 2^30 bytes. In the mainframe and z/OS context,...
GBP - Group Buffer Pool
A Group Buffer Pool (GBP) is a shared data cache residing in an IBM Coupling Facility (CF), primarily used by DB2 for z/OS Data Sharing Groups. Its ma...
GCF - Global Configuration File
The Global Configuration File (GCF) in the z/OS environment primarily refers to a dataset or member used by **IBM Tivoli Monitoring (ITM)** components...
GCS - Group Control System
GCS (Group Control System) is a component of the **VM/ESA** (Virtual Machine/Enterprise System Architecture) operating system, designed to provide a *...
GDPS - Geographically Dispersed Parallel Sysplex
GDPS (Geographically Dispersed Parallel Sysplex) is an IBM z/OS-based high-availability and disaster recovery solution designed to provide continuous ...
GDT - Global Descriptor Table
The Global Descriptor Table (GDT) is a data structure used in **x86 architecture** (Intel/AMD processors) to define memory segments, their base addres...
GE - Greater or Equal
`GE` (Greater or Equal) is a relational operator used in IBM mainframe environments, primarily within JCL and programming languages like COBOL, to per...
Gemstone - Object database
Gemstone/S (and its successor Gemstone/J) is an object-oriented database management system (OODBMS) designed to store and manage complex data structur...
General - Widely applicable
In the context of mainframe systems, "General - Widely applicable" describes a component, concept, or practice that is fundamental, versatile, and uti...
General Purpose Register - GPR storage
General Purpose Registers (GPRs) are high-speed storage locations within the Central Processing Unit (CPU) of an IBM mainframe, used to temporarily ho...
General Register
A general register is a high-speed storage location directly within the CPU, used by the processor to temporarily hold data, addresses, or intermediat...
Generate
In the context of IBM mainframe systems, "generate" refers to the process of creating or producing specific artifacts, configurations, or executable c...
Generation
In the context of z/OS, a **generation** refers to a specific, chronologically ordered version or instance of a data set within a **Generation Data Gr...
Generation Data Group
A Generation Data Group (GDG) is a collection of chronologically related non-VSAM datasets on z/OS that share a common base name. Its primary purpose ...
Generator
A Generator, in the mainframe context, refers to a specialized software tool or utility designed to automatically create source code (e.g., COBOL, PL/...
Generic - General purpose
In the context of IBM mainframe systems and z/OS, "generic" or "general purpose" refers to a component, utility, language, or system designed for broa...
Generic Alert
A Generic Alert is a standardized, structured notification mechanism used within IBM z/OS and its subsystems to report significant events, problems, o...
Geographically Dispersed
In the context of IBM mainframe systems and z/OS, "geographically dispersed" refers to an architectural strategy where critical computing resources, d...
Geometry - Spatial Layout
In the context of IBM mainframe systems, "Geometry" primarily refers to the physical and logical organization of data on Direct Access Storage Devices...
GET
In the context of IBM IMS (Information Management System) databases, `GET` refers to a set of DL/I (Data Language/I) calls used by application program...
GETMAIN
`GETMAIN` is a z/OS macro instruction used by programs to dynamically acquire contiguous blocks of virtual storage from the system during execution. I...
GFS - Grandfather Father Son
GFS (Grandfather Father Son) is a widely used data retention and backup strategy in mainframe environments, particularly for sequential datasets like ...
GHz - Gigahertz
Gigahertz (GHz) is a unit of frequency representing one billion cycles per second. In the context of IBM mainframe systems, it primarily measures the ...
GID - Group Identifier
A Group Identifier (GID) in z/OS is a numeric value assigned to a **RACF group profile** that uniquely identifies a group of users for security and ac...
Global
In the context of IBM mainframe systems, "global" refers to resources, data, or settings that are accessible, visible, or affect a broad scope, typica...
Global Catalog - Shared Catalog
The Global Catalog is a critical **VSAM Key-Sequenced Data Set (KSDS)** that serves as the master index for all user catalogs within a z/OS system or ...
Global Queue - Shared Work Queue
In the context of IBM z/OS, a Global Queue, often referred to as a Shared Work Queue, is a data structure residing in a **Coupling Facility (CF)** tha...
Global Resource Serialization (GRS) Locking
Global Resource Serialization (GRS) is a z/OS facility that provides system-wide serialization of resources across multiple z/OS systems within a sysp...
Global Variable
In the context of z/OS, a global variable refers to a data item or storage area that is accessible and modifiable by multiple independent program modu...
Glossary - Term definitions
A glossary, in the context of mainframe and z/OS technologies, is an alphabetical list of specialized terms and their definitions, designed to clarify...
GMT - Greenwich Mean Time
Greenwich Mean Time (GMT) is a historical time standard based on the mean solar time at the Prime Meridian (0° longitude) in Greenwich, London. In the...
Goal - Target objective
In the context of z/OS Workload Manager (WLM), a "goal" represents a target objective or performance specification defined for a workload. It dictates...
Goal Mode - WLM service policy
Goal Mode is the primary operational mode of the z/OS Workload Manager (WLM) where performance objectives are defined for workloads, and WLM dynamical...
Governor
A governor in z/OS is a system mechanism designed to control and limit the consumption of specific resources (e.g., CPU, I/O, elapsed time) by workloa...
GPL - General Public License
The General Public License (GPL) is a widely used free software license that guarantees end users the freedom to run, study, share, and modify the sof...
GPR - General Purpose Register
A General Purpose Register (GPR) is a high-speed storage location within the CPU on IBM mainframe systems (z/Architecture) used to temporarily hold da...
GPS - Global Positioning System
Global Positioning System (GPS) is a satellite-based radionavigation system that provides geolocation and time information to a GPS receiver anywhere ...
Graceful Shutdown
A **graceful shutdown**, also known as an **orderly shutdown**, is the controlled and systematic termination of a z/OS system, a specific subsystem (l...
Grade
In the mainframe context, "Grade" or "Quality Level" refers to the classification or assessment of the performance, reliability, availability, securit...
Gradual - Incremental Change
Gradual or incremental change in the mainframe context refers to a strategic approach of implementing modifications, upgrades, or migrations in small,...
Grain
In mainframe computing, "grain" refers to the level of detail or the scope of an entity, such as data, a lock, or a processing unit. It describes the ...
Granularity
In the mainframe context, **granularity** refers to the level of detail or the size of the smallest unit at which a resource, data, or process is mana...
Grant
In the mainframe context, a `GRANT` statement or command is used to bestow specific access privileges or permissions to users, groups, or roles on var...
Graphic - Visual element
In the context of IBM mainframe systems and z/OS, a graphic refers to a visual representation or image element, typically generated or processed by ma...
Graphical User Interface
A Graphical User Interface (GUI) in the mainframe context refers to a client-side application that provides a visual, interactive interface for users ...
Graphics - Visual elements
In the context of IBM mainframe systems and z/OS, "graphics" refers to the programmatic generation and display of visual information, often character-...
Grep
`grep` (Global Regular Expression Print) is a powerful command-line utility within z/OS UNIX System Services (USS) used to search plain-text data sets...
Grid - Two-dimensional array
A two-dimensional array, often referred to as a **grid** or **table**, is a data structure that organizes data in rows and columns. In mainframe progr...
Grid Computing
Grid computing, in the context of mainframe systems, refers to a distributed computing paradigm where multiple heterogeneous or homogeneous computing ...
Ground - Reference point
In the context of IBM mainframe systems and z/OS, the term "Ground - Reference point" does not refer to a specific software component, programming con...
Group
A logical collection of user IDs within the z/OS security environment, primarily managed by **RACF** (Resource Access Control Facility), used to simpl...
Group Buffer Pool
A Group Buffer Pool (GBP) is a shared cache structure residing in the IBM z/OS Coupling Facility (CF) that manages data pages (table spaces and index ...
Grouping
Grouping, in the mainframe context, refers to the process of organizing or categorizing related items—such as data records, system resources, workload...
Growth
In the mainframe context, **growth** refers to the increase in size, capacity, or demand for various system resources, data storage, application workl...
GRS - Global Resource Serialization
Global Resource Serialization (GRS) is a z/OS component that manages access to shared resources across multiple z/OS systems within a sysplex. Its pri...
GRSCNF
`GRSCNF` (Global Resource Serialization Configuration) is a member within `SYS1.PARMLIB` that defines the configuration for Global Resource Serializat...
GT - Greater Than
`GT` (Greater Than) is a relational operator used in mainframe programming languages, utilities, and JCL to compare two values and determine if the fi...
GTE - Greater Than or Equal
GTE (Greater Than or Equal) is a relational operator used in mainframe programming languages and utilities, such as COBOL, JCL, and DFSORT, to compare...
GTF - Generalized Trace Facility
The Generalized Trace Facility (GTF) is a powerful z/OS component used to capture detailed, event-driven trace data from various parts of the system. ...
GTRACE - Generalized Trace
GTRACE, or Generalized Trace, is a powerful z/OS system component that provides a flexible and comprehensive facility for tracing system events, progr...
Guard
A "guard" in mainframe computing refers to a protective mechanism designed to ensure the integrity, consistency, or controlled access of resources, da...
Guardian - Monitoring Process
A Guardian, in the context of z/OS, refers to a dedicated background process or agent designed to continuously observe, collect, and analyze performan...
Guest - Virtual machine
A guest, in the context of mainframe virtual machines, refers to an operating system (such as z/OS, Linux on Z, or z/VSE) that runs within a virtual m...
GUI - Graphical User Interface
A Graphical User Interface (GUI) is a type of user interface that allows users to interact with electronic devices through graphical icons and visual ...
GUID - Globally Unique Identifier
A GUID (Globally Unique Identifier) is a 128-bit number used to uniquely identify information in computer systems. While a general computing concept, ...
Guideline - Recommended Practice
In the mainframe context, a guideline or recommended practice refers to a set of established principles, procedures, or conventions that, while not st...
GWA - Global Work Area
The Global Work Area (GWA) is a storage area within a CICS (Customer Information Control System) region that is accessible to all transactions and pro...
H
HCD
An ISPF dialog used to define and manage I/O configuration for z/OS systems. HCD provides a centralized interface for configuring channels, control un...
Hercules
An open-source software implementation of mainframe hardware that allows mainframe operating systems (MVS, z/OS, z/VM, etc.) to run on commodity hardw...
HIPAA
Healthcare data protection regulation that many mainframe systems must comply with when processing medical information. HIPAA requires specific securi...
HLQ
The first part of a dataset name that typically identifies the owner or category of the dataset. HLQs are used for organizing datasets and controlling...
Hexadecimal
Hexadecimal (often shortened to "hex") is a base-16 number system that uses sixteen distinct symbols: 0-9 for values zero to nine, and A-F for values ...
HA - High Availability
High Availability (HA) refers to the capability of an IT system or component to remain operational and accessible for a high percentage of the time, m...
Hack
In the mainframe context, a "hack" primarily refers to an unauthorized attempt or successful act of gaining access to a z/OS system, its data, or reso...
HAD - Hardware Activity Display
HAD (Hardware Activity Display) is a z/OS component that provides real-time and historical performance data for various hardware resources, including ...
Halfword
A halfword is a fundamental unit of data storage and processing on IBM mainframe systems, consisting of two bytes (16 bits) of data. It is primarily u...
Halt
In the mainframe context, a **halt** refers to the intentional or unintentional cessation of execution for a program, task, subsystem, or the entire z...
Hand - Manual operation
In the context of mainframe operations, "hand" or "manual operation" refers to any task or process that requires direct human intervention, typically ...
Handshake
In the context of mainframe and z/OS, a **handshake** refers to a multi-step communication process between two entities (e.g., a client and a server, ...
Handle
In the context of IBM z/OS and mainframe programming, a **handle** is an opaque identifier, typically an integer or a pointer, returned by a system se...
Handler - Processing routine
A handler, in the context of z/OS, is a specialized processing routine or program module designed to intercept, manage, and respond to specific events...
Handling
In the context of IBM mainframe systems and z/OS, "handling" refers to the systematic management and processing of various conditions, events, or data...
Handoff
In mainframe computing, "handoff" or "transfer of control" refers to the act of one program, module, or system component relinquishing execution contr...
Hang
In the context of IBM mainframe systems and z/OS, a "hang" refers to a state where a program, task, subsystem, or the entire operating system ceases t...
HAO - Host Access Option
The Host Access Option (HAO) is a key component of the IBM CICS Transaction Gateway (CTG) that enables non-CICS client applications (such as Java, .NE...
Hard - Permanent or physical
In mainframe computing, the term "hard" often describes attributes that are physical, permanent, fixed, or difficult to change without significant sys...
Hard Coded
In the mainframe context, a "hard-coded" value refers to data, parameters, or logic that is directly embedded within a program's source code or a JCL ...
Hard Copy
In the mainframe context, **hard copy** refers to any physical, tangible output generated by the system, typically printed on paper. This includes rep...
Hard Disk
A hard disk, in the context of IBM mainframe systems, refers to the physical direct access storage device (DASD) used for persistent, high-speed stora...
Hard Error
A hard error in the mainframe context refers to a permanent, unrecoverable failure of a hardware component, I/O operation, or software resource that p...
Hard Limit
A hard limit in the mainframe context refers to a fixed, non-negotiable maximum boundary for a system resource, operational parameter, or software com...
Hardware
Hardware, in the mainframe context, refers to the physical components of the IBM zSystems platform, including processors, memory, storage devices, I/O...
Hardware Configuration Definition
Hardware Configuration Definition (HCD) is an interactive, menu-driven component of z/OS that defines and manages the hardware configuration of an IBM...
Harmony - Compatibility
In the mainframe context, **compatibility** refers to the ability of different hardware, software, and data components within the z/OS ecosystem to co...
Harvesting Resources
In the z/OS context, "harvesting resources" refers to the systematic collection and aggregation of operational data, performance metrics, log entries,...
Hash
In the mainframe context, a **hash** (or hash value, message digest) is a fixed-size alphanumeric string generated from an input of arbitrary size dat...
Hash Function
A hash function is an algorithm that transforms an input of arbitrary size (e.g., a record key) into a fixed-size value, known as a **hash value**, **...
Hash Table
A hash table, also known as a hash map, is a data structure that implements an associative array abstract data type, mapping keys to values. It uses a...
Hashing
Hashing, in the mainframe context, refers to the process of transforming an input key (such as a record key or data block) into a fixed-size value, kn...
HASP - Houston Automatic Spooling Priority
HASP, an acronym for Houston Automatic Spooling Priority, was an early and influential software component for IBM mainframe operating systems, primari...
HCD - Hardware Configuration Definition
Hardware Configuration Definition (HCD) is a z/OS component used to define, activate, and manage the hardware configuration of an IBM mainframe system...
HCM - Hardware Configuration Manager
HCM (Hardware Configuration Manager) is a z/OS component and a graphical user interface (GUI) tool used to define, manage, and activate hardware confi...
HD - Hard Disk
In the mainframe context, a Hard Disk (HD) refers to the physical magnetic storage medium that constitutes a Direct Access Storage Device (DASD). It i...
HDA - Hard Disk Assembly
In the context of IBM mainframe systems, an HDA (Hard Disk Assembly) refers to the sealed, electromechanical unit that forms the core physical compone...
HDR - Header
In the context of IBM mainframe systems and z/OS, a "header" (HDR) refers to the initial segment of a data record, file, message, or data block that c...
HDUMP - Hexadecimal Dump
A hexadecimal dump (HDUMP) is a formatted display of the raw contents of memory, registers, or a data set, presented in both hexadecimal and character...
Head - First element
In mainframe systems, "Head - First element" refers to the initial, primary, or leading component within a sequence, structure, or process. This conce...
Header
A header, in the mainframe and z/OS context, refers to a block of data or metadata that precedes the main body of information (e.g., a file, message, ...
Heap
In the z/OS environment, a **heap** refers to a region of dynamic memory that programs can request and release at runtime. It is primarily used for al...
Heartbeat - Alive signal
A heartbeat, in the mainframe context, refers to a periodic, low-overhead signal transmitted by a system, application, or component to indicate its op...
Heat - Thermal Issue
In the context of IBM mainframe systems, a **thermal issue** refers to an abnormal increase in operating temperature within the mainframe hardware or ...
Heavy - Resource intensive
In mainframe computing, "heavy" or "resource-intensive" describes a workload, program, transaction, or process that consumes a significant amount of s...
Height
In the context of IBM mainframe systems, "height" primarily refers to the vertical dimension of a display screen, such as a 3270 terminal, or the numb...
HELD - Held output
`HELD` output, often referred to as "held output," is a status assigned to a SYSOUT dataset within the Job Entry Subsystem (JES) spool. When SYSOUT is...
Helper Component
A helper component in the mainframe context refers to a modular program, routine, or utility designed to perform a specific, often reusable, supportin...
Heterogeneous
In the context of IBM z/OS and enterprise computing, "heterogeneous" refers to environments, systems, or data structures composed of diverse and often...
Heuristic - Rule of thumb
In the context of z/OS and mainframe computing, a heuristic is a practical, experience-based technique or "rule of thumb" used to solve problems, make...
Hex - Hexadecimal
Hexadecimal, often shortened to Hex, is a base-16 number system used extensively in mainframe computing to represent binary data in a more compact and...
Hexadecimal Dump
A hexadecimal dump, often simply called a "dump," is a raw, byte-by-byte representation of a specific portion of memory or a data area, displayed in h...
HFS - Hierarchical File System
HFS (Hierarchical File System) is a file system implementation within z/OS UNIX System Services (USS) that provides a POSIX-compliant, byte-stream ori...
HH - Hour
`HH` is a common two-digit representation for the hour component of a time or timestamp, typically following a 24-hour clock format (00-23). In mainfr...
HHC
HHC is the standard prefix used by the Hercules mainframe emulator for its console messages, commands, and log entries. It serves to clearly identify ...
JCL
JCL (Job Control Language) is a scripting language used on IBM mainframe operating systems like z/OS to instruct the operating system on how to execut...
Hierarchical - Tree structured
In the context of IBM mainframes and z/OS, "hierarchical" refers to a data organization or system structure where elements are arranged in a tree-like...
Hierarchy - Ranked structure
In the mainframe context, a hierarchy refers to a ranked or tree-like organizational structure where elements are arranged in levels of importance, co...
High Availability - HA systems
High Availability (HA) refers to systems designed to operate continuously without significant downtime, ensuring uninterrupted access to critical appl...
High Level Language - HLL programming
High Level Languages (HLLs) in the mainframe context are programming languages that provide a strong abstraction from the underlying hardware architec...
High Order
"High Order" refers to the most significant part of a data item, such as a byte, word, or field, in terms of its value or position. In the context of ...
High Performance
...
High Water Mark
In the mainframe context, a **High Water Mark** refers to the maximum value or peak level that a specific resource, metric, or counter has reached ove...
Higher
In the mainframe context, "higher" typically refers to a position, rank, or level that is superior, more abstract, or takes precedence over another. I...
Hiperbatch
Hiperbatch is a z/OS feature designed to significantly improve the I/O performance of batch jobs by caching frequently accessed data in memory (expand...
Hiperspace - High performance space
Hiperspace, or High Performance Space, is a type of virtual storage in z/OS designed to provide high-speed access to large amounts of data by keeping ...
Historical Data
Historical data, in the mainframe context, refers to information collected and retained over a period to track system performance, application activit...
Hit
In the context of mainframe systems, a **hit** signifies a successful access to a requested resource, data block, or program module that is found in a...
Hit Rate
In the mainframe context, a **hit rate** measures the percentage of times a requested data item is found in a faster access mechanism, such as a buffe...
Hit Ratio
In the context of IBM z/OS and mainframe systems, the Hit Ratio represents the percentage of times a requested data block or record is successfully fo...
HLL - High Level Language
In the mainframe context, a High-Level Language (HLL) is a programming language that provides a strong abstraction from the underlying hardware archit...
HMC - Hardware Management Console
The Hardware Management Console (HMC) is a dedicated workstation, either physical or virtual, that provides a single point of control for managing and...
HOD - Host On Demand
IBM Host On-Demand (HOD) is a Java-based, web-to-host connectivity solution that provides secure, browser-based access to mainframe (3270), AS/400 (52...
HOL - Head of Line
In the mainframe context, Head of Line (HOL) refers to a situation where the first item in a queue or the first task requesting a shared resource prev...
Hold
In z/OS, "Hold" primarily refers to a mechanism used to temporarily prevent a job from executing or to prevent a SYSOUT dataset from being processed (...
Hold Queue
A Hold Queue, within the IBM z/OS environment, is a designated waiting area managed by the Job Entry Subsystem (JES) where jobs, SYSOUT datasets, or o...
Hole
In mainframe computing, a "hole" refers to a missing record or a gap in a logically or physically ordered sequence of data within a file, dataset, or ...
Home
In the context of z/OS, "Home" most commonly refers to a user's **home directory** within **UNIX System Services (USS)**, which serves as the default ...
Home Address
In the context of IBM mainframe Direct Access Storage Devices (DASD), the **Home Address** is a special control block written at the very beginning of...
Homogeneous
In the context of IBM mainframe systems and z/OS, **homogeneous** refers to an environment, system, or data structure where all components, elements, ...
Hook - Intercept point
In the context of IBM mainframe systems and z/OS, a "hook" or "intercept point" refers to a predefined location or mechanism within an operating syste...
Hop - Network jump
In the context of z/OS and mainframe networking, a "hop" refers to a single segment of a data packet's journey across a network, from one network devi...
Horizontal
In mainframe computing, "horizontal" refers to the distribution of workload, data, or processing across multiple equivalent, independent instances or ...
Horsepower
In the context of IBM mainframes, **horsepower** refers to the raw processing capability or computational power of the system. It quantifies the amoun...
Host
In the context of mainframe computing, the **host** refers to the central, powerful IBM mainframe system that provides the primary computing resources...
Host Code Page
A Host Code Page, in the context of IBM mainframes and z/OS, refers to the character encoding scheme used by the operating system and its applications...
Host Language
...
Host Name
In the context of IBM mainframe systems and z/OS, a Host Name is a human-readable label assigned to a specific z/OS instance (typically an LPAR) withi...
Host Variable - Program variable
A host variable is a program variable declared within an application program (e.g., COBOL, PL/I, C/C++) that is used to exchange data with an embedded...
Hosted - Running on system
"Hosted - Running on system" on the mainframe refers to the execution of applications, services, or workloads directly on the IBM z/Architecture hardw...
Hot
In mainframe computing, "hot" refers to data, code, or system resources that are subject to exceptionally high access frequency or intense utilization...
Hot Fix
In the mainframe context, a hot fix is an immediate, urgent software patch or correction applied directly to a production system to resolve a critical...
Hot Key - Shortcut key
In the mainframe context, a **Hot Key** or **Shortcut Key** refers to a single key or a combination of keys on a 3270 terminal or emulator keyboard th...
Hot Spot - Contention Point
In the context of IBM mainframe systems and z/OS, a **hot spot** or **contention point** refers to a specific resource, data element, or code path tha...
Hot Standby
A high-availability configuration where a secondary system (or set of resources) is fully operational, continuously synchronized with the primary syst...
Hot Swap
In the context of IBM z/OS and mainframe hardware, a hot swap refers to the ability to replace or add a hardware component (e.g., a disk drive, power ...
Hotspot
In the context of mainframe systems, a **hotspot** refers to a specific resource (data, code, or hardware component) that is disproportionately access...
Housekeeping
In the context of IBM mainframe systems and z/OS, "housekeeping" refers to the set of routine, often scheduled, maintenance tasks performed to ensure ...
HP
HP, commonly known as Hewlett Packard, is a technology company primarily associated with personal computers, printers, and enterprise server solutions...
HPA - High Performance Access
High Performance Access (HPA) is a feature within IBM z/OS that significantly enhances the I/O performance of Virtual Storage Access Method (VSAM) dat...
HPO - High Performance Option
HPO, or High Performance Option, refers to a collection of advanced features and optimizations within IBM's DFSORT utility on z/OS designed to signifi...
HPU - Hardware Processing Unit
A Hardware Processing Unit (HPU) in the IBM mainframe context refers to a specialized processor designed to execute specific types of workloads, there...
HQM - Highly Qualified Master
While not a universally standardized acronym in the mainframe lexicon, a "Highly Qualified Master" (HQM) within the z/OS context refers to a master fi...
HR - Human Resources
In the context of mainframe systems, HR (Human Resources) refers to the suite of enterprise applications and business processes designed to manage an ...
HSCDMUX - HSCD Multiplexer
HSCDMUX, or HSCD Multiplexer, is a crucial communication component within the IBM zSystems hardware management infrastructure, typically residing on t...
HSM - Hierarchical Storage Manager
HSM (Hierarchical Storage Manager) is a z/OS component that automates the management of data across different levels of storage, from fast, expensive ...
HTML - Hypertext Markup Language
HTML, in the mainframe context, refers to the standard markup language used to structure and present web content that often originates from or interac...
HTTP - Hypertext Transfer Protocol
HTTP (Hypertext Transfer Protocol) is an application-layer protocol for transmitting hypermedia documents, such as HTML, over the internet. In the z/O...
HTTPS - HTTP Secure
HTTPS (Hypertext Transfer Protocol Secure) is the secure version of HTTP, primarily used on z/OS to provide encrypted communication and secure identif...
Hub Monitoring Server
A Hub Monitoring Server, within the IBM OMEGAMON monitoring suite, acts as the central aggregation and distribution point for monitoring data collecte...
Human - Person using system
In the context of IBM mainframe systems, a "Human - Person using system" refers to any individual who interacts with the z/OS operating system, its ap...
HV - Hypervisor
In the IBM mainframe context, a hypervisor is a layer of software or firmware that creates and runs virtual machines (VMs). The primary hypervisor on ...
HVLCB - High Volume Lock Control Block
The High Volume Lock Control Block (HVLCB) is an internal control block used by IBM's IMS (Information Management System) to manage database locks for...
HVS - High Volume Sharing
HVS, or High Volume Sharing, refers to a set of `VSAM` (Virtual Storage Access Method) sharing options and techniques designed to enable multiple `CIC...
HVSHARE - High Volume Share
HVSHARE (High Volume Share) is a specific attribute within **VSAM Record Level Sharing (RLS)** designed to optimize performance and concurrency for **...
HVTOC - High Capacity VTOC
HVTOC, or High Capacity VTOC, is an enhanced version of the Volume Table of Contents specifically designed to support the significantly larger storage...
HW - Hardware
In the mainframe context, hardware refers to the physical components of an IBM Z-series system, including processors, memory, I/O channels, storage de...
Hybrid
In the mainframe context, "hybrid" refers to the architectural strategy of integrating traditional IBM z/OS systems and applications with modern distr...
Hyperlink
A hyperlink, or simply a link, is a reference within a digital document or web interface that, when activated, directs the user to another location wi...
Hyperspace
Hyperspace is an extended storage object in z/OS that provides a large, contiguous block of virtual storage (up to 2GB) for an application's use. Unli...
Hypertext
Hypertext, within the context of IBM z/OS, refers to text that contains embedded links to other text, documents, or media, enabling non-linear navigat...
Hyperthread
While `Hyperthread` is a term commonly associated with Intel processors, the analogous technology in IBM z/Architecture is called **Simultaneous Multi...
Hypervisor
A hypervisor, often referred to as a virtual machine monitor (VMM), is a layer of software or firmware that creates and runs virtual machines (VMs). O...
Hyphen
In IBM z/OS mainframe systems, the hyphen, also known as a dash, is a significant special character (`X'60'` in EBCDIC) used for various purposes, inc...
Hypothesis
In the context of IBM mainframe systems and z/OS, a hypothesis refers to a proposed explanation, a testable proposition, or an educated guess made as ...
Hz - Hertz frequency
Hertz (Hz) is the standard international unit of frequency, representing one cycle per second. In the mainframe and z/OS context, it primarily quantif...
I
Initial Program Load
Initial Program Load (IPL) is the process of starting or restarting an IBM mainframe system, loading the z/OS operating system (or another OS like z/V...
IAAS
Cloud computing model increasingly used for mainframe workload migration and hybrid architectures, providing virtualized computing resources over the ...
IDCAMS
A utility program for managing VSAM datasets, catalogs, and performing various file operations. IDCAMS (Integrated Data Cluster Access Method Services...
IDMS
A network model database management system from Broadcom (formerly CA Technologies), widely used before relational databases. IDMS uses a CODASYL netw...
IMS
IBM's hierarchical database and transaction processing system, designed for high-volume online and batch processing. IMS has been a cornerstone of ent...
IMS DB
The database component of IMS using a hierarchical data model for organizing information. IMS DB represents data as tree structures with parent-child ...
IMS DC
The transaction processing component of IMS for managing online terminal interactions and message-driven applications. IMS DC provides high-volume tra...
Initiator
A z/OS component that selects jobs from the JES input queue and allocates resources for their execution. Initiators bridge between the job entry subsy...
IOCS
The portion of the operating system that manages all input and output operations, handling physical I/O, buffering, error recovery, and device managem...
IOCP
Utility used to define I/O configuration for mainframe systems, generating IOCDS (I/O Configuration Data Set) that describes hardware configuration to...
IPL
The mainframe equivalent of booting or restarting the operating system. IPL loads the z/OS nucleus into memory and initializes the system for operatio...
ISPF
IBM's menu-driven interface for z/OS providing tools for program development, file management, and system administration. ISPF is the primary interact...
ISQL
Tool for executing SQL statements and managing DB2 databases interactively. ISQL provides an immediate feedback environment for database queries and a...
I/O - Input Output
In the mainframe and z/OS context, I/O (Input/Output) refers to the fundamental process of transferring data between the central processing unit (CPU)...
I/O Bound
An I/O bound workload or program is one whose overall execution time is primarily limited by the speed and volume of its input/output (I/O) operations...
I/O Channel
An I/O Channel is a dedicated hardware component within an IBM mainframe system responsible for managing the high-speed transfer of data between main ...
I/O Configuration - Device Setup
In z/OS, I/O Configuration refers to the process of defining and managing the hardware components that allow the mainframe to communicate with externa...
I/O Device
An I/O (Input/Output) device in the mainframe context refers to any peripheral hardware component that allows the z/OS system to receive data (input) ...
I/O Interrupt
In the z/OS environment, an I/O interrupt is an asynchronous event signal generated by an I/O device or its channel subsystem to the CPU, indicating t...
I/O Operation
In the mainframe context, an **I/O Operation** (Input/Output Operation) refers to the process of transferring data between the central processing unit...
I/O Request
An I/O Request, often synonymous with a transfer request in the mainframe context, is a fundamental operation initiated by a program or the z/OS opera...
I/O Subsystem
The I/O Subsystem in a mainframe environment refers to the integrated hardware and software components responsible for managing all data transfers bet...
IAC - Inter Application Communication
In the z/OS environment, Inter Application Communication (IAC) refers to the mechanisms and protocols that enable different applications or components...
IACAPPL
`IACAPPL` (often referred to simply as an `APPL` name) is the unique identifier for an application program within a VTAM (Virtual Telecommunications A...
IAM - Indexed Access Method
IAM (Indexed Access Method) is a third-party, high-performance **VSAM-compatible access method** for IBM z/OS systems. It provides significant perform...
IAS - Immediate Access Storage
IAS, or Immediate Access Storage, is a historical term referring to the fastest form of storage directly accessible by the CPU, primarily used for act...
IASID - Internal ASID
An IASID (Internal Address Space ID) is a specific type of ASID (Address Space ID) used by the z/OS operating system itself to identify and manage its...
IBC - Inter-Block Gap
The Inter-Block Gap (IBC), also known as the Inter-Record Gap (IRG), is a physical blank space on a magnetic tape that separates consecutive data bloc...
IBM - International Business Machines
IBM (International Business Machines Corporation) is a multinational technology and consulting company renowned as the primary developer and vendor of...
IBMLINK
IBMLINK was a comprehensive, secure online service provided by IBM, primarily to its enterprise customers, for accessing technical support, product in...
IC
In the context of IBM mainframes and z/OS, the **Instruction Counter (IC)** is a critical component of the CPU's Program Status Word (PSW) that holds ...
ICAM - Integrated Computer Aided Manufacturing
Integrated...
ICB - Intermediate Control Block
An Intermediate Control Block (ICB) is a data structure created by the z/OS Linkage Editor or Loader within a load module. It contains control informa...
ICC - Inter-Component Communication
Inter-Component Communication (ICC) refers to the mechanisms and techniques used by different software components, programs, tasks, or address spaces ...
ICD - Interface Control Document
An Interface Control Document (ICD) is a formal technical specification that defines the precise interaction, data exchange, and communication protoco...
ICF - Integrated Catalog Facility
The Integrated Catalog Facility (ICF) is a fundamental component of z/OS that provides a centralized, high-performance cataloging system for all datas...
ICF Catalog
The ICF Catalog is the primary catalog structure in z/OS, responsible for managing information about datasets and VSAM objects. It serves as a central...
ICMF - ISPF Configuration Management Facility
ICMF, the ISPF Configuration Management Facility, is a component of IBM's ISPF (Interactive System Productivity Facility) that provides centralized co...
Icon
In the context of IBM mainframe systems and z/OS, an icon refers to a small graphical symbol used within modern graphical user interface (GUI) tools a...
ICS - Intermediate Control Storage
Intermediate Control Storage (ICS) is a specialized, high-speed storage area within an IBM mainframe processor that holds microcode instructions. Its ...
ICSS - Interactive Computing and Control Facility
ICSS (Interactive Computing and Control Facility) is a powerful, low-level interactive facility within IBM z/OS that provides system programmers and a...
ICSF - Integrated Cryptographic Service Facility
ICSF (Integrated Cryptographic Service Facility) is a z/OS component that provides a secure, high-performance cryptographic services platform, leverag...
ICU - International Components for Unicode
ICU (International Components for Unicode) is a mature, widely used set of C/C++ and Java libraries that provides robust support for Unicode and softw...
ID - Identifier
In the mainframe context, an **Identifier (ID)** is a unique name or label assigned to a resource, entity, user, program, or data component to disting...
IDA - Interactive Debug Aid
IDA, or Interactive Debug Aid, is an IBM-supplied interactive debugging utility for z/OS that allows developers to diagnose problems in batch and onli...
IDAA - DB2 Analytics Accelerator
The IBM Db2 Analytics Accelerator (IDAA) is a hybrid appliance or software solution designed to significantly accelerate complex analytical and data w...
IDCAMS - Access Method Services utility
IDCAMS (Access Method Services) is a powerful, multi-purpose utility program on IBM z/OS used primarily for managing VSAM (Virtual Storage Access Meth...
IDE - Integrated Development Environment
An Integrated Development Environment (IDE) in the z/OS context is typically a client-side graphical user interface (GUI) application that provides co...
Identical
In the mainframe context, "identical" refers to two or more entities (such as datasets, files, records, programs, or system configurations) having pre...
Identification
In the z/OS environment, identification refers to the process of asserting and verifying the identity of a user, program, or system component attempti...
Identifier
In the context of IBM mainframe systems and z/OS, an **identifier** is a symbolic name or code assigned to a program element, data item, resource, or ...
Identify
In the mainframe and z/OS context, "identify" refers to the initial process where a user or a system component asserts its unique identity to the oper...
Identity
In z/OS, identity refers to the unique set of attributes that authenticate and authorize a user, a started task, or a system component to access resou...
Idle
In the mainframe context, "idle" describes a state where a system resource, component, task, or user session is available and operational but not acti...
Idle Time
Idle time, in the context of IBM z/OS and mainframe systems, refers to the period during which a specific resource, most commonly the Central Processi...
IDP - Interactive Debug Program
IDP, or Interactive Debug Program, is a foundational interactive debugging tool on IBM z/OS that allows developers to step through the execution of ap...
IDR - Install Data Record
An Install Data Record (IDR) is a component of a Program Temporary Fix (PTF) or Authorized Program Analysis Report (APAR) fix that contains specific i...
IDS - Intrusion Detection System
An Intrusion Detection System (IDS) on IBM z/OS is a security mechanism designed to monitor system activities, network traffic, and audit logs for sig...
IE
The acronym "IE" does not refer to a single, standalone technology or component within the IBM mainframe z/OS ecosystem. Instead, it serves as a commo...
IEA - Initialization and Tuning
IEA refers to a critical set of system parameters and components in z/OS that control the system's initialization process and allow for fine-tuning of...
IEBCOPY
IEBCOPY is a standard IBM z/OS utility program used primarily for copying, compressing, merging, and selecting members within partitioned data sets (P...
IEBGENER
IEBGENER is a standard IBM utility program in z/OS primarily used for copying, reformatting, and converting sequential data sets or members of partiti...
IEBEDIT
IEBEDIT is a standard IBM z/OS utility program, part of DFSMSdfp, primarily used for editing sequential datasets or members of partitioned datasets (P...
IEBPTPCH
`IEBPTPCH` is an IBM-supplied z/OS utility program primarily used to copy, print, or punch records from sequential data sets, including physical seque...
IEBUPDTE
`IEBUPDTE` is a standard IBM z/OS utility program used primarily for maintaining sequential datasets and partitioned datasets (PDS or PDSE) by adding,...
IEC - I/O Error Code
An I/O Error Code (IEC) is a specific numerical or hexadecimal value returned by the z/OS operating system or an access method to indicate the nature ...
IEEMB833 - Initialization module
IEEMB833 is the z/OS Master Scheduler Initialization module, a critical component loaded during the Initial Program Load (IPL) process. Its primary fu...
IEFBR14
`IEFBR14` is an IBM-supplied dummy program for z/OS that performs no actual processing logic. Its primary purpose is to provide a valid program name f...
IEFJOBS
`IEFJOBS` is a z/OS system service (provided as a macro) that allows authorized programs to retrieve detailed information about jobs currently active,...
IEFUSI
`IEFUSI` is a System Management Facilities (SMF) user exit in z/OS that is invoked by the Job Entry Subsystem (JES2 or JES3) *before* a batch job or s...
IEEE - Institute of Electrical and Electronics Engineers
The Institute of Electrical and Electronics Engineers (IEEE) is a global professional association and a leading developer of international standards f...
IEH Utilities
`IEH` is a prefix for a set of **legacy IBM z/OS data set utility programs** primarily used for managing and manipulating data sets, volumes, and cata...
IEHLIST
`IEHLIST` is an IBM z/OS utility program used to list various types of information about datasets and volumes. Its primary purpose is to display the c...
IEHMOVE
`IEHMOVE` is an IBM mainframe utility program used primarily for moving or copying datasets between volumes or within the same volume on z/OS systems....
IEHPROGM
`IEHPROGM` is an IBM utility program on z/OS systems primarily used for performing various maintenance functions on `Partitioned Datasets (PDS)` and `...
IER - Invalid ENQ Request
An IER (Invalid ENQ Request) is an error condition in z/OS that occurs when a program attempts to acquire or release a serially reusable resource usin...
IFACE - Interface
In the context of IBM z/OS, an interface defines a standardized point of interaction or communication between distinct software components, hardware d...
IFC - Information Facility Center
"IFC - Information Facility Center" is not a standard, officially recognized IBM product name or acronym within the z/OS ecosystem. However, conceptua...
IFI - Instrumentation Facility Interface
The Instrumentation Facility Interface (IFI) is a programmatic interface provided by IBM DB2 for z/OS that allows external applications to access a wi...
IFID - Internal Format Identifier
The Internal Format Identifier (IFID) is a critical field within IBM z/OS that uniquely identifies the internal format and structure of a data set, pa...
IFL - Integrated Facility for Linux
An Integrated Facility for Linux (IFL) is a specialized processor engine on IBM Z mainframes designed exclusively to run Linux operating systems and t...
IFREQ - Interface Request
IFREQ (Interface Request) is a CICS command used to initiate a program link to a program residing in a *different* CICS region. It is a fundamental co...
IFS - Installable File System
An Installable File System (IFS) in z/OS refers to a type of file system that can be dynamically mounted and integrated into the z/OS UNIX System Serv...
IG - Index Generation
IG (Index Generation) refers to the process of creating or rebuilding an **Alternate Index (AIX)** for a **VSAM Key-Sequenced Data Set (KSDS)**. This ...
IGC - System service prefix
IGC is a prefix used by IBM for system service routines in z/OS. These routines provide fundamental operating system functions and are typically re-en...
IGD
`IGD` is a standard three-character prefix used by IBM z/OS to identify modules, macros, and messages associated with the Data Facility Storage Manage...
IGF - GRS prefix
The `IGF` prefix is an internal identifier used by the Global Resource Serialization (GRS) component within z/OS. It designates resources that are exc...
IGV - Volume mount prefix
A volume mount prefix, such as `IGV`, is a standardized leading character string within a **Volume Serial (VOLSER)** that helps categorize or identify...
IGW - VTOC services prefix
`IGW` is a standard prefix used in z/OS for system modules, macros, and services primarily associated with **VTOC (Volume Table of Contents)** managem...
IGX - Cross-memory prefix
In z/OS, the "cross-memory prefix" refers to the internal mechanisms and control blocks used by cross-memory services to manage and secure inter-addre...
IHC
`IHC` is the default command prefix used to identify and issue **JES3 (Job Entry Subsystem 3)** operator commands from the z/OS system console or thro...
IKJ - TSO/E prefix
`IKJ` is the standard three-character prefix used by IBM to identify modules, macros, and control blocks specifically associated with the Time Sharing...
IKJEFT01
`IKJEFT01` is an IBM-supplied z/OS utility program that allows the execution of TSO/E commands, CLISTs, or REXX EXECs within a batch job. It effective...
ILC - Instruction Length Code
The Instruction Length Code (ILC) is a 2-bit field within the Program Status Word (PSW) on IBM mainframe systems that indicates the length of the last...
ILE - Integrated Language Environment
On IBM z/OS,...
ILI - Interrupted Loop Indicator
An Interrupted Loop Indicator (ILI) is a programmer-defined flag or variable used within mainframe applications, typically written in COBOL or PL/I, t...
Image
In the mainframe context, an **Image Copy** refers to a complete, point-in-time backup of a data set, a database object (such as a DB2 table space or ...
Image Copy
An image copy, in the context of mainframe databases like DB2 for z/OS and IMS, is a consistent, point-in-time backup of a database object (e.g., a ta...
Immediate
In mainframe computing, "immediate" refers to operations or data that are processed or accessed directly and synchronously, often without intermediate...
Immutable
In the context of mainframe systems, an **immutable** entity (such as data, an object, or a state) is one that, once created, cannot be modified or al...
Impact Analysis
Impact Analysis, in the mainframe context, is the systematic process of identifying and evaluating the potential consequences and ripple effects of a ...
IMPL - Implementation
In the mainframe context, "implementation" refers to the comprehensive process of designing, coding, testing, and deploying a software solution, syste...
Implement
In the mainframe context, "implement" refers to the comprehensive process of developing, configuring, deploying, and making a software solution, syste...
Implementation - Realization
Implementation, in the mainframe context, refers to the comprehensive process of transforming a designed solution into a functional, operational compo...
Data Import
In the mainframe and z/OS context, **data import** refers to the process of transferring data from an external source into a mainframe system, applica...
IMS - Information Management System
IMS (Information Management System) is a high-performance, hierarchical database management system (IMS DB) and a powerful transaction manager (IMS TM...
IMS Connect - TCP/IP gateway
IMS Connect is a TCP/IP gateway that enables external client applications to communicate with IMS Transaction Manager (IMS TM) and IMS Database Manage...
IMS Control Region
The IMS Control Region is the central, indispensable z/OS address space that manages all activities within an IMS (Information Management System) envi...
IMS DB - IMS Database
IMS DB (Information Management System Database) is a high-performance, hierarchical database management system (DBMS) developed by IBM, primarily used...
IMS DC - IMS Data Communications
IMS Data Communications (IMS DC) is the online transaction processing (OLTP) and message processing component of IBM's Information Management System (...
IMS Message Queue
The IMS Message Queue is a critical component of the IMS DB/DC (Database/Data Communications) environment, serving as a persistent storage area on DAS...
IMS Region - IMS address space
An IMS region, often synonymous with an IMS address space in the z/OS context, refers to a specific z/OS address space where IMS components or IMS-dep...
IMS TM - IMS Transaction Manager
IMS TM (Transaction Manager), formerly known as IMS DC (Data Communications), is a high-performance, high-volume online transaction processing (OLTP) ...
IMU - Image Manager Update
IMU, or Image Manager Update, is an IBM z/OS utility primarily used to apply updates and modifications to the system's `IPL` (Initial Program Load) te...
IN - Input or Inside
In the context of IBM mainframe systems and z/OS, "IN" primarily refers to data or resources provided to a program, job, or system for processing. It ...
Inactive
In the mainframe context, "inactive" describes a state where a resource, process, or component is not currently performing its primary function or pro...
Inbound
In the mainframe context, "inbound" refers to data, requests, or transactions originating from external systems, users, or other computing environment...
INC - Increment
In mainframe computing, "increment" refers to the operation of increasing a numeric value, typically by a fixed amount, most commonly by one. This fun...
Incarnation - Instance
An **instance** in the mainframe context refers to a specific, independent execution or occurrence of a program, transaction, or resource within the z...
Incident
In the mainframe and z/OS context, an **incident** is an unplanned interruption to an IT service or a degradation in the quality of an IT service. It ...
INCLUDE
In mainframe computing, an `INCLUDE` refers to a directive or statement that instructs a compiler, assembler, interpreter, or utility to insert the co...
Inclusive - Including specified
In the context of mainframe and z/OS, "inclusive" or "including specified" refers to a range or set of values where the boundary values themselves are...
Incoming
Refers to the process or state of an external entity, such as data streams, network traffic, transaction requests, or job submissions, arriving at and...
Incompatible
In the context of IBM mainframe systems, "incompatible" refers to the inability of two or more components, such as software versions, hardware devices...
Incomplete - Not finished
In the context of mainframe operations and data processing, "Incomplete - Not finished" describes a state where a job, task, transaction, or data set ...
Inconsistent - Not matching
In the context of mainframe systems, "inconsistent" refers to a state where data, system configurations, or application states do not align with expec...
Increment
In the context of mainframe computing, an increment refers to the action of increasing a numerical value, counter, or pointer by a specific amount, ty...
Incremental
In the context of mainframe systems, "incremental" refers to a process or operation that deals only with changes or additions since a previous point i...
Incremental Backup
An incremental backup is a backup strategy that captures only the data that has changed or been added since the *last* backup of *any type* (full or i...
IND - Index
An index in the mainframe context is a specialized data structure designed to accelerate data retrieval operations by providing a fast lookup path to ...
Indent
In the mainframe context, "indent" refers to the practice of positioning text, code, or data elements a specific number of character positions away fr...
Independent
In the z/OS environment, "independent" refers to a component, process, or resource that operates with a degree of isolation, meaning it is **not depen...
Indexs
An index in mainframe systems is an ordered lookup structure that allows for rapid direct access to records within a dataset or rows within a database...
Index Key - Search key
In mainframe data management, an **index key** (often synonymous with **search key**) is a field or a combination of fields within a record or row tha...
Index Space
An Index Space is a physical storage structure within IBM Db2 for z/OS that holds the data pages for a single Db2 index. It is the underlying storage ...
Indexed
In the mainframe context, "indexed" refers to a method of organizing data where a separate structure, known as an index, is created to facilitate rapi...
Indexing
Indexing, in the mainframe context, refers to the process of creating and maintaining a specialized data structure that provides a fast access path to...
Indicate
In mainframe computing, to **indicate** refers to the act or mechanism of signaling a specific status, condition, or outcome of a process, operation, ...
Indicator
In mainframe programming, particularly COBOL, an indicator is a single-character data item or a special register used to signal a condition, status, o...
Indirect Data Set Reference
In the z/OS environment, an **indirect data set reference** occurs when a `DD` statement in JCL specifies a data set name that does not directly point...
Indirect Addressing - Pointer-based
Indirect addressing, in the mainframe context, refers to accessing data or instructions not directly by their absolute memory address, but by an addre...
Individual - Single entity
In the context of mainframe systems, an "individual - single entity" refers to any distinct, atomic component or item within the z/OS environment that...
Indoubt Transaction
An **indoubt transaction** is a distributed transaction that has successfully completed its "prepare" phase within a two-phase commit (2PC) protocol b...
Induced
In the context of mainframe systems, "induced" refers to a state, event, or condition that is directly caused or triggered by a specific action, progr...
Industry - Business sector
"Industry" in the context of mainframe systems refers to the specific business sectors or verticals (e.g., financial services, insurance, retail, gove...
Inefficient - Poor performance
In the z/OS context, "inefficient - poor performance" refers to a condition where a mainframe application, system component, or process consumes more ...
Inequality
In mainframe computing, "inequality" or "not equal" refers to a fundamental comparison operation used in conditional logic to determine if two values ...
Inet - Internet
The Internet, in the context of IBM z/OS, refers to the global system of interconnected computer networks that utilizes the Internet Protocol Suite (T...
Infer
In the context of mainframe systems, particularly database management systems like Db2 for z/OS, "infer" refers to the process by which a system compo...
Infinite Loop
An infinite loop in a mainframe context refers to a sequence of instructions within a program (e.g., COBOL, Assembler, PL/I) or a JCL procedure that e...
Infix Notation
Infix notation is a common method for writing expressions where operators are placed *between* their operands. This human-readable format is widely us...
Inflection
In a general linguistic context, **inflection** refers to the modification of a word to express different grammatical categories such as tense, mood, ...
INFO - Information
In the mainframe context, **Information** refers to structured and contextualized data that has been processed, stored, and managed by IBM z/OS system...
Inform - Notifying
In the mainframe context, "Inform - Notifying" refers to the comprehensive set of mechanisms and processes by which the z/OS operating system, its sub...
Information
In the mainframe context, **information** refers to data that has been processed, organized, structured, or presented in a way that gives it meaning a...
Information Center - Help facility
The Information Center, specifically referring to IBM Documentation (formerly IBM Knowledge Center), is a centralized, web-based repository provided b...
Information Management - Data Control
Information Management - Data Control refers to the comprehensive set of facilities, mechanisms, and processes within IBM mainframe operating systems ...
Infrastructure
In the context of IBM mainframe systems and z/OS, **infrastructure** refers to the foundational hardware, software, network, and physical facilities r...
Ingress
Ingress, in the context of z/OS, refers to all network traffic originating from external sources that is directed into the mainframe system. This inbo...
Inherit
In the context of z/OS, "inherit" primarily refers to a child process receiving attributes, environment variables, or open file descriptors from its p...
Inhibit
In the context of mainframe systems, "inhibit" refers to the action or state of blocking, restricting, or preventing a specific operation, access, or ...
INI - Initialization File
On z/OS, an initialization file (often conceptually, or literally in z/OS UNIX System Services) is a data set member or a file containing configuratio...
Init - Initialize
In the context of IBM mainframe and z/OS, "initialize" refers to the process of preparing a resource, such as a dataset, storage area, or device, for ...
Initialization
Initialization, in the mainframe context, refers to the process of preparing a system, subsystem, program, or resource for operational use. It involve...
Initialize
...
Initiation
In z/OS, "initiation" refers to the process by which the Job Entry Subsystem (JES) selects a submitted job from its input queue and prepares it for ex...
Injection
In the mainframe context, **injection** refers to a class of security vulnerabilities where untrusted data is sent to an interpreter as part of a comm...
Inline
In the mainframe context, "inline" primarily refers to data, procedures, or code that is embedded directly within the same input stream or file as the...
Inline Expansion
Inline expansion, often referred to as inlining, is a compiler optimization technique where the compiler replaces a function or subroutine call with t...
INN - Internal Network Node
An Internal Network Node (INN) is a type 4 node within an IBM Systems Network Architecture (SNA) network, primarily responsible for routing data traff...
Nested Constructs
In mainframe computing, **nested constructs** refer to the practice of embedding one programming or JCL element within another, where the inner elemen...
Inner Join
An `INNER JOIN` is a fundamental operation in relational databases, particularly within DB2 for z/OS, used to combine rows from two or more tables. It...
Innovation - New approach
In the context of IBM mainframe systems and z/OS, "innovation - new approach" refers to the strategic adoption and implementation of novel methods, to...
Inode
In the context of z/OS, an Inode (index node) is a fundamental data structure used exclusively within the **z/OS UNIX System Services (z/OS UNIX)** fi...
Input - Data entering
In the context of IBM mainframe systems and z/OS, "input" refers to any data or commands supplied to a program, application, or the operating system f...
Input Dataset
An input dataset in z/OS refers to a collection of logically related records or data that serves as the source information for a program or utility. I...
Input Queue
In the z/OS environment, an Input Queue is a temporary storage area where incoming work, such as JCL streams for batch jobs or transaction requests fo...
Input Stream
In the context of IBM z/OS, an input stream refers to a sequential collection of data, commands, or control statements that are fed into the system or...
Inquiry
In the mainframe context, an inquiry refers to a real-time, read-only request for specific information from a database or system, typically initiated ...
Insert - Adding data
In the mainframe context, "inserting" or "adding data" refers to the programmatic or utility-driven process of creating new records or entries within ...
Inside - Within boundary
In the context of IBM mainframe systems and z/OS, "inside - within boundary" refers to the state of an entity (such as a program, data, or process) be...
`INSPECT` Statement
The `INSPECT` statement in COBOL is a powerful verb used to examine, count occurrences of, and replace specific characters or character strings within...
Software Installation
In the z/OS environment, software installation is the structured process of deploying new or updated program products, operating system components, or...
Installation - Site-specific system
An "installation" in the mainframe context refers to the complete, operational IBM mainframe environment deployed at a specific customer location. It ...
Installation Exit
An Installation Exit, often referred to as a "site exit" or "user exit," is a specific point within an IBM mainframe operating system (like z/OS) or a...
Instance
In the context of IBM mainframe systems and z/OS, an "instance" refers to a specific, unique occurrence or execution of a program, a running copy of a...
Instant
In the context of IBM z/OS and mainframe systems, "instant" typically refers to operations or data availability that occur with extremely low latency,...
Instantiate
In the context of mainframe computing, particularly within object-oriented programming paradigms like **OO COBOL** or **Java on z/OS**, to instantiate...
Instruction
An instruction in the mainframe context is the most fundamental, atomic operation that a Central Processing Unit (CPU) can execute. It is a command en...
Instruction Cache - I-cache
The Instruction Cache (I-cache) is a small, high-speed memory component integrated within the CPU of an IBM mainframe. Its primary purpose is to store...
Instruction Counter
In IBM mainframe processors, the Instruction Counter, often referred to as the Program Counter (PC) in broader computing contexts, is a special-purpos...
Instruction Set
An instruction set, in the context of IBM mainframes, is the complete collection of operations or commands that a specific Central Processing Unit (CP...
Instrumentation
In mainframe computing, instrumentation refers to the practice of embedding code or utilizing system facilities to collect data about the performance,...
Insufficient
In the context of IBM z/OS and mainframe systems, "insufficient" refers to a condition where a required system resource, such as memory (storage), pro...
Insulate - Isolating
In the mainframe context, "insulating" or "isolating" refers to the practice of creating logical or physical boundaries to separate resources, data, o...
Integer
An integer, in the mainframe context, refers to a whole number (without fractional components) used as a fundamental data type in programming language...
Interrupt
An interrupt in z/OS is an asynchronous or synchronous event that causes the CPU to suspend its current program execution and transfer control to a pr...
Intake
In the mainframe context, "intake" refers to the process by which a z/OS system, application, or component receives data, commands, or requests from e...
Integrate
In the mainframe context, "integrate" refers to the process of combining disparate applications, data sources, or systems to enable them to work toget...
Integration
In the mainframe context, **Integration** refers to the process of connecting disparate systems, applications, or data sources, often running on z/OS,...
Integrity - Correctness
In the mainframe context, "Integrity - Correctness" refers to the accuracy, consistency, and reliability of data and system operations. It ensures tha...
Integrity Checking
Integrity checking in the mainframe context refers to the process of verifying that data, system components, or application states are correct, consis...
Intel
Intel is a leading manufacturer of microprocessors and semiconductor devices, primarily known for its x86 and x64 instruction set architectures. In th...
Intellisense - Auto-completion
Intellisense and auto-completion, in the context of mainframe development, refer to features within modern Integrated Development Environments (IDEs) ...
Intelligent - Smart behavior
In the context of IBM z/OS mainframes, "intelligent - smart behavior" refers to the system's inherent capability to dynamically and autonomously manag...
High-level Language
A High-level Language (HLL) is a programming language that provides a strong abstraction from the details of the computer's hardware, allowing program...
Intensity - Strength level
In the context of IBM mainframe systems and 3270 terminals, "intensity" primarily refers to a **display attribute** that controls the brightness or pr...
Interact - Communicating
In the mainframe context, "interacting" or "communicating" refers to the diverse methods and protocols employed by users, applications, or external sy...
Interactive
In the mainframe context, "interactive" refers to a mode of operation where a user directly communicates with a system or application in real-time, re...
Interactive Debug - Online debugging
Interactive debugging, often referred to as online debugging in the mainframe context, is a method of executing a program under the control of a speci...
Interactive Problem Control System - IPCS debugging
IPCS (Interactive Problem Control System) is a core z/OS component that provides an interactive, command-driven environment for analyzing system and p...
Interblock Gap
The Interblock Gap (IBG) is a physical, non-data area on a magnetic storage medium, such as tape or older Direct Access Storage Devices (DASD), that s...
Intercept
In mainframe computing, an "intercept" refers to the programmatic capture and processing of a system event, program execution flow, or data access bef...
Interchange - Exchange
In the mainframe context, "Interchange" or "Exchange" primarily refers to the process of **data interchange**, which is the transfer of data between d...
Interconnect
In the mainframe context, an interconnect refers to the high-speed, dedicated hardware and software mechanisms that enable communication and data tran...
Interdependency
In the context of IBM mainframe systems and z/OS, interdependency refers to the mutual reliance and sequential or concurrent relationships between var...
Interface
In the mainframe context, an **interface** serves as a defined point of interaction or communication between distinct software components, hardware de...
Interface Control Block
An **Interface Control Block (ICB)**, within the mainframe context, is a structured data area used to facilitate communication and control information...
Interference - Disruption
In the context of z/OS, "Interference - Disruption" refers to situations where the operational behavior or resource consumption of one workload, appli...
Interim/Temporary
In the mainframe context, "interim" or "temporary" refers to resources, data, or processes that are short-lived, transient, or designed for a limited ...
Interleave - Alternating
In z/OS, interleaving refers to the operating system's technique of executing or processing multiple independent tasks, programs, or I/O operations by...
Interleaved
In the context of z/OS and mainframe computing, "interleaved" refers to the arrangement or processing of distinct elements (such as data records, I/O ...
Intermediate Stage
An intermediate stage refers to a temporary or transitional phase within a larger mainframe process, such as a batch job, online transaction, or data ...
Intermittent
In the context of mainframe systems, "intermittent" describes a condition, error, or performance characteristic that occurs sporadically, unpredictabl...
Internal
In the mainframe and z/OS context, "internal" refers to components, processes, data, or resources that reside or are managed *within* the z/OS operati...
Internal Reader
The Internal Reader is a facility within the Job Entry Subsystem (JES) that allows an executing program or system component to submit Job Control Lang...
Internal Sort - In-memory sort
An internal sort, also known as an in-memory sort, is a sorting operation where the entire dataset to be sorted fits completely within the available m...
Internationalization (i18n) on z/OS
Internationalization (i18n) on z/OS refers to the design and implementation of mainframe applications and systems to support diverse linguistic, cultu...
Internet
From a z/OS perspective, the Internet represents the global, publicly accessible network infrastructure that enables IBM mainframe systems and their a...
Internet Protocol (IP) Networking
Internet Protocol (IP) Networking on z/OS refers to the implementation and utilization of the Internet Protocol suite for network communication within...
Internals - Internal Workings
In the mainframe context, "internals" refers to the intricate, low-level operational mechanisms, data structures, algorithms, and control flows within...
Interoperability
Interoperability, in the mainframe context, refers to the ability of z/OS systems, applications, and data to seamlessly exchange information and work ...
Interpret - Executing or explaining
In the z/OS environment, "interpret" primarily refers to the process where a program or system component directly reads, analyzes, and performs the ac...
Interpreter - Runtime Executor
In the mainframe context, an interpreter is a program that directly executes instructions written in a programming or scripting language without requi...
Interprocess
In the z/OS environment, **interprocess** refers to the communication, coordination, or data exchange between distinct, concurrently executing program...
Interrecord Gap - IRG spacing
The Interrecord Gap (IRG), also known as IRG spacing, is a physical blank space on a magnetic tape medium that separates consecutive blocks of data. I...
Interrogate - Questioning
In the mainframe context, "interrogate" refers to the act of querying, examining, or probing a system, subsystem, resource, program, or data store to ...
Interrupt Handler - Interrupt processor
An interrupt handler, also known as an interrupt processor, is a specialized routine within the z/OS operating system's supervisor that is invoked asy...
Interrupt Vector - Handler address
In the context of IBM z/Architecture and z/OS, an interrupt vector handler address is a specific entry point within a system-defined table that the CP...
Intersection - Common elements
In the mainframe context, "intersection" when referring to "common elements" typically denotes the process of identifying and extracting records or da...
Interval
An interval, in the context of IBM mainframe systems, refers to a specific, measurable duration of time used to control, schedule, monitor, or report ...
Interval Control
Interval Control in CICS (Customer Information Control System) is a core component responsible for managing time-dependent operations, allowing CICS a...
Intervention - Manual action
In the context of IBM mainframe systems and z/OS, an "intervention" or "manual action" refers to a required human interaction with the system, typical...
Intrapartition Queue
An Intrapartition Queue (IPQ) in CICS is a type of **transient data queue** used for communication and data exchange *within a single CICS region*. It...
Intranet
An Intranet is a private, internal computer network within an organization that uses Internet protocols and technologies (like TCP/IP, HTTP) to share ...
Intrinsic - Built-in
In mainframe computing, "intrinsic" or "built-in" refers to functions, statements, or capabilities that are an inherent part of a programming language...
Introspection
In the context of IBM mainframe systems and z/OS, introspection refers to the ability of a program or system component to examine its own structure, s...
Intrusion
Intrusion, in the mainframe context, refers to any unauthorized attempt or successful act of gaining access to z/OS system resources, data, or applica...
Intuitive
While not a technical term specific to mainframe systems, "intuitive" in the z/OS context refers to the ease with which a user can understand, learn, ...
Invalid
In the mainframe context, "invalid" refers to data, commands, or operations that do not conform to predefined rules, formats, or constraints, leading ...
Invalidate
To mark data, a resource, a cache entry, or a security credential as no longer valid, current, or authorized, forcing a re-evaluation or re-acquisitio...
Invariant
In the context of z/OS and mainframe programming, an "invariant" component, typically referring to program code, is one that does not modify itself du...
Software Inventory
A **Software Inventory** on a z/OS system is a comprehensive catalog of all installed software products, their versions, maintenance levels (PTFs, APA...
Inverse - Opposite
In the context of mainframe systems, "inverse" or "opposite" refers to a conceptual relationship where one element, process, or value is the reverse, ...
Inversion - Reversal
In the mainframe context, "Inversion" primarily refers to the creation and use of **inverted files** or **inverted indexes** to facilitate rapid data ...
Invert - Reversing
In the context of IBM z/OS and mainframe data processing, "invert" or "reversing" primarily refers to the process of changing the logical order of rec...
Investigate - Examining
In the mainframe context, "investigate" or "examining" refers to the systematic process of analyzing system behavior, application execution, data stat...
Invocation - Calling
In the mainframe context, **invocation** or **calling** refers to the process by which one program or routine transfers control to another program, su...
Invoice
In the context of IBM mainframe systems, an invoice refers to the digital representation or physical output of a billing document that is generated, p...
Invoke
In the mainframe context, "invoke" refers to the act of initiating the execution of a program, subroutine, function, or service from another program o...
Invoker - Calling program
In the context of IBM mainframe systems, an **invoker** or **calling program** is a program or module that initiates the execution of another program,...
IOS - Input/Output Supervisor
The Input/Output Supervisor (IOS) is a fundamental component of the z/OS operating system kernel responsible for managing all I/O operations between t...
IOT
In the mainframe context, IOT refers to the integration of data generated by interconnected physical devices, sensors, and other "things" into enterpr...
IP
IP, or Internet Protocol, is a foundational network layer protocol within the TCP/IP suite that dictates how data packets are addressed, fragmented, a...
IPC - Inter-Process Communication
In the mainframe context, Inter-Process Communication (IPC) refers to the mechanisms that allow independent programs, tasks, or address spaces within ...
IPCS - Interactive Problem Control System
The Interactive Problem Control System (IPCS) is a powerful z/OS component used by system programmers and support personnel to analyze system dumps, t...
IPL - Initial Program Load
IPL, or Initial Program Load, is the fundamental process of starting or restarting an IBM mainframe system, specifically an LPAR running z/OS. It invo...
IPLINFO - IPL Information
`IPLINFO` is a z/OS operator command used to display crucial information about the last Initial Program Load (IPL) of the z/OS system. It provides det...
IPLTEXT - IPL Text
`IPLTEXT` refers to a user-defined text string that is displayed on the system console during the z/OS Initial Program Load (IPL) process. Its primary...
IPO - Initial Program Offering
In the context of IBM mainframe systems, an Initial Program Offering (IPO) refers to the initial, uncustomized version of an IBM software product (suc...
IPRT - Install Product Runtime
IPRT, or Install Product Runtime, refers to the phase within the IBM System Modification Program/Extended (SMP/E) process where a software product's e...
IPS - Instructions Per Second
IPS (Instructions Per Second) is a fundamental metric representing the raw number of machine instructions a CPU can execute in one second. While a bas...
IPT - Installation Performance Tool
IPT, or Installation Performance Tool, refers to the systematic process and associated tools used to measure, analyze, and validate the performance of...
IPv4 - Internet Protocol version 4
IPv4 is the fourth version of the Internet Protocol, serving as the foundational, connectionless protocol for addressing and routing data packets acro...
IPv6 - Internet Protocol version 6
IPv6 (Internet Protocol version 6) is the latest version of the Internet Protocol, designed to succeed IPv4. On IBM z/OS, IPv6 provides an expanded ad...
IPX - Internetwork Packet Exchange
IPX (Internetwork Packet Exchange) is a network layer protocol primarily associated with Novell NetWare networks, designed for routing packets between...
IQI - Interrupted Queue Item
An Interrupted Queue Item (IQI) in IBM MQ for z/OS refers to a message that has been put onto a queue or retrieved from a queue as part of a unit of w...
IR - Internal Reader
The Internal Reader (IR) is a component of the Job Entry Subsystem (JES) (either JES2 or JES3) on z/OS that allows programs or system components to su...
IRC
Inter-Region Communication (IRC) is a fundamental CICS facility that enables multiple CICS regions (address spaces) to communicate with each other and...
IRD - Integrated Roadmap Documentation
Integrated Roadmap Documentation (IRD) in the mainframe context refers to a comprehensive set of documents that outline the strategic evolution, plann...
IREQ - Interrupt Request
An Interrupt Request (IREQ) in the z/OS environment is a signal to the CPU that an event has occurred requiring immediate attention, causing the CPU t...
IRLM - IMS Resource Lock Manager
IRLM (IMS Resource Lock Manager) is a z/OS component that provides centralized lock management services for shared resources, primarily within IMS and...
IRQ - Interrupt Request
In the context of IBM mainframes and z/OS, an interrupt is a hardware-generated or software-generated signal that causes the CPU to suspend its curren...
IRS - Internal Revenue Service
The Internal Revenue Service (IRS) is the U.S. federal agency responsible for collecting taxes and administering the Internal Revenue Code. It is one ...
IRX
`IRX` is the program name for the REXX interpreter in z/OS, serving as the primary entry point for executing REXX (Restructured Extended Executor) exe...
IS - Information Systems
In the mainframe context, an Information System (IS) refers to the comprehensive, integrated set of hardware, software, data, processes, and people de...
ISA
"ISA" most commonly refers to **Instruction Set Architecture**, which defines the abstract model of a computer's processor, specifying the set of inst...
ISAM - Indexed Sequential Access Method
ISAM (Indexed Sequential Access Method) is an older file organization technique on IBM mainframes that allows records to be accessed both sequentially...
ISC - Inter-System Communication
Inter-System Communication (ISC) is a core CICS facility that enables applications in one CICS region to communicate with and access resources or invo...
ISDN - Integrated Services Digital Network
Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other ...
ISG - IBM Systems Group
The IBM Systems Group (ISG) was a significant organizational division within IBM responsible for the development, manufacturing, sales, and support of...
ISI - Inter-System Interconnect
Inter-System Interconnect (ISI) refers to the high-speed, direct communication links that facilitate data exchange and resource sharing between multip...
ISM - Interactive Storage Management
Interactive Storage Management (ISM) on z/OS refers to the capability for system programmers and storage administrators to directly manage and control...
ISN - Internal Sequence Number
An Internal Sequence Number (ISN) is a unique, system-assigned identifier used by IBM's Information Management System (IMS) to internally identify and...
ISO - International Standards Organization
The International Standards Organization (ISO) is a non-governmental organization that develops and publishes international standards across various i...
ISOC - Internet Society
The Internet Society (ISOC) is a global non-profit organization dedicated to ensuring the open development, evolution, and use of the Internet. While ...
Isolation
In the mainframe and z/OS context, **isolation** refers to the practice and architectural mechanisms used to separate computing resources, workloads, ...
Isolation - Separation
In the context of IBM z/OS, isolation and separation refer to the fundamental architectural principles and mechanisms that prevent different workloads...
Isolation Level - Transaction visibility
Isolation level defines how and when changes made by one transaction become visible to other concurrent transactions in a multi-user database environm...
ISPEXEC
`ISPEXEC` is the primary command interface used to invoke ISPF (Interactive System Productivity Facility) services programmatically on z/OS. It allows...
ISPF - Interactive System Productivity Facility
ISPF (Interactive System Productivity Facility) is a full-screen, menu-driven application that runs under TSO/E on IBM z/OS. It provides a primary int...
ISPLIB - ISPF Library
`ISPLIB` refers to a `DDNAME` (Data Definition Name) in the z/OS environment that represents a concatenation of partitioned data sets (PDS or PDSE) us...
ISPPROF - ISPF Profile
`ISPPROF` is a personal dataset allocated to each TSO user on z/OS, primarily used by the **Interactive System Productivity Facility (ISPF)** to store...
ISR
In the context of IBM mainframe systems and z/OS, `ISR` most commonly refers to the **ISPF Program Development Facility** (option 2 on the ISPF Primar...
ISS - Internet Security Systems
Internet Security Systems (ISS) was a prominent cybersecurity company acquired by IBM in 2006. While its products were not native z/OS components, ISS...
Issue
In the context of mainframe and z/OS, an **issue** refers to a problem, defect, incident, or any unexpected behavior that deviates from normal system ...
ISSUER - Originator
In the context of z/OS and enterprise computing, an **Issuer** typically refers to the entity (often a Certificate Authority) that signs and validates...
IST - VTAM message prefix
`IST` is a three-character prefix used by IBM's Virtual Telecommunications Access Method (VTAM) for messages issued to the z/OS system console, SYSLOG...
IT - Information Technology
In the mainframe context, Information Technology (IT) refers to the comprehensive infrastructure, systems, services, and personnel responsible for man...
ITA - IT Architecture
IT Architecture, within the mainframe context, is the comprehensive blueprint and design principles that guide the structure, behavior, and implementa...
Italic - Slanted text
Italic text, or slanted text, is a typographical style where characters are slanted to the right, primarily used for emphasis, titles, foreign words, ...
Iterate - Repeating
In mainframe computing, "iteration" refers to the process of repeatedly executing a block of code, a set of instructions, or a job step until a specif...
Iteration
In the context of mainframe and z/OS, an iteration refers to a single execution or pass through a block of code or a sequence of operations within a l...
Iterative
In the mainframe context, "iterative" refers to a process or program segment designed to repeat a set of operations multiple times, often with slight ...
ITSO - International Technical Support Organization
The IBM International Technical Support Organization (ITSO) is a global team of technical professionals within IBM that creates and publishes practica...
ITT - Integrated Task Time
`Integrated Task Time (ITT)` is a cumulative measure of the total processor time consumed by a task or address space in the z/OS environment. It inclu...
ITU - International Telecommunication Union
The International Telecommunication Union (ITU) is a specialized agency of the United Nations responsible for coordinating global telecommunication ne...
IUCV - Inter-User Communication Vehicle
IUCV (Inter-User Communication Vehicle) is a core z/VM facility that provides a message-based communication mechanism between virtual machines (VMs) r...
IV - Initialization Vector
An Initialization Vector (IV) is a fixed-size input used in conjunction with a secret key to randomize the encryption process, particularly with block...
IVP - Installation Verification Procedure
An Installation Verification Procedure (IVP) is a set of jobs, programs, and data designed to confirm that a newly installed or updated software produ...
IVT - Interrupt Vector Table
In the context of IBM mainframe systems and z/OS, the Interrupt Vector Table (IVT) is a critical system control block containing the entry points (add...
IWM - Installation Wide Management
Installation Wide Management (IWM) is a z/OS component that provides a framework for defining and enforcing resource management policies across an ent...
J
Java on z/OS
IBM's Java Development Kit optimized for mainframe systems, enabling modern application development using Java on z/OS. Provides full Java SE capabili...
JES2/JES3
The z/OS component that manages job scheduling, input/output processing, and print services. JES acts as the interface between users submitting work a...
Job
A unit of work submitted to the system for batch processing, defined by JCL statements. A job contains one or more job steps that execute sequentially...
Job Class
A categorization assigned to jobs for scheduling and resource allocation purposes. Job classes enable workload management by grouping similar jobs tog...
Job Step
An individual program execution within a job, defined by an EXEC statement in JCL. A job can contain multiple steps that execute sequentially. A job s...
Job Class2
...
JOB Statement
...
J2EE - Java 2 Enterprise Edition
J2EE (now Jakarta EE) is a platform for developing and deploying enterprise-level, multi-tier applications using the Java programming language. In the...
J2SE - Java 2 Standard Edition
J2SE, now commonly referred to as Java SE (Standard Edition), is the core platform for developing and deploying general-purpose Java applications. On ...
JA - Job Accounting
Job Accounting (JA) in z/OS refers to the systematic process of collecting and recording detailed information about the resources consumed by jobs, st...
JAD - Joint Application Development
JAD (Joint Application Development) is a methodology that brings together end-users, developers, and subject matter experts in structured, facilitated...
Jam - Blockage or interference
In the context of IBM mainframe systems, "jam" refers to a state of blockage, interference, or contention that prevents the normal, unimpeded operatio...
JAR - Java Archive
A JAR (Java Archive) is a platform-independent file format used to aggregate many Java class files, associated metadata, and resources (text, images, ...
JAVA
JAVA is an object-oriented programming language widely used on IBM z/OS for developing modern enterprise applications, web services, and middleware. I...
Java Bean
A Java Bean is a reusable software component written in Java that adheres to specific conventions for properties, events, and methods, making it intro...
Java Virtual Machine (JVM) runtime
The Java Virtual Machine (JVM) runtime on z/OS is a software component that provides a runtime environment for executing Java bytecode. It acts as an ...
JavaScript
JavaScript, within the context of IBM mainframe and z/OS, primarily functions as a client-side scripting language used to build modern web-based appli...
JAX - Java API for XML
JAX (Java API for XML) is a collection of Java APIs that provide standard ways to process XML documents within Java applications. On z/OS, JAX enables...
JCB - Job Control Block
A Job Control Block (JCB) is an in-memory control block created by the Job Entry Subsystem (JES) for each batch job submitted to the z/OS system. It s...
JCDS - Job Class Data Set
The Job Class Data Set (JCDS) is a VSAM Key-Sequenced Data Set (KSDS) used by JES2 to store persistent definitions for job classes. It ensures that jo...
JCL - Job Control Language
JCL (Job Control Language) is a scripting language used on IBM mainframe operating systems, primarily z/OS, to instruct the system on how to execute a...
JCLIN - JCL Input
JCLIN, often referring to the `JCLIN` control statement within utilities like `IEBCOPY`, is a mechanism used to update the directory entries of partit...
JCLLIB - JCL Library
`JCLLIB` (JCL Library) refers to a partitioned dataset (PDS or PDSE) that stores JCL procedures (`PROC`s). It serves as a central repository for reusa...
JCT - Job Control Table
The Job Control Table (JCT) is a critical in-memory control block within the z/OS operating system, primarily managed by the Job Entry Subsystem (JES)...
JDB - Java Debugger
JDB (Java Debugger) is a command-line tool provided with the Java Development Kit (JDK) that allows developers to debug Java applications. On z/OS, it...
JDBC - Java Database Connectivity
JDBC (Java Database Connectivity) is a standard Java API that provides a common interface for Java applications to connect to and interact with variou...
JDK - Java Development Kit
The Java Development Kit (JDK) on z/OS is a comprehensive software package that provides the tools and runtime environment necessary for developing, c...
JES - Job Entry Subsystem
JES (Job Entry Subsystem) is a core component of the z/OS operating system responsible for managing the input and output of jobs. It acts as an interm...
JES2 - Job Entry Subsystem 2
JES2 (Job Entry Subsystem 2) is a core component of the IBM z/OS operating system responsible for managing the input, scheduling, execution, and outpu...
JES3 - Job Entry Subsystem 3
JES3 (Job Entry Subsystem 3) is a core component of the IBM z/OS operating system responsible for managing job input, scheduling, output processing, a...
JESXCF - JES Cross-System Coupling Facility
JESXCF is a component of the z/OS operating system that enables Job Entry Subsystem (JES2 or JES3) instances running on different z/OS systems within ...
JIB - Job Information Block
The Job Information Block (JIB) is an internal z/OS control block that contains crucial, static information about a running batch job or started task....
Jiffies - Timer ticks
While the term `jiffies` is primarily associated with Unix-like operating systems to denote a system timer tick, in the context of IBM z/OS, it refers...
JIT - Just In Time
In the context of IBM z/OS, Just In Time (JIT) refers to a compilation technique employed by the `IBM Java Virtual Machine (JVM)` that dynamically tra...
JITC - Joint Interoperability Test Command
The Joint Interoperability Test Command (JITC) is a U.S. Department of Defense (DoD) organization responsible for testing and certifying the interoper...
JMF - Job Management Facility
JMF, or Job Management Facility, is a component of z/OS that provides a programmatic interface for managing batch jobs. It allows applications to inte...
JMON - Job Monitor
JMON (Job Monitor) is a component of IBM Developer for z/OS (IDz) and IBM Z Open Development (IZOD) that provides real-time monitoring and control cap...
JMS - Java Message Service
JMS (Java Message Service) is a Java API that provides a common way for Java applications to create, send, receive, and read messages using enterprise...
JNDI - Java Naming and Directory Interface
JNDI (Java Naming and Directory Interface) is a standard Java API that provides a unified interface for Java applications to access various naming and...
Job Accounting - Usage recording
Job accounting, in the z/OS context, refers to the systematic process of collecting, recording, and analyzing resource utilization data for all types ...
Job Card
The Job Card is the first statement in a Job Control Language (JCL) stream, serving as the primary identifier for a batch job submitted to the z/OS op...
Job Entry - Submission process
Job entry, in the context of IBM z/OS, refers to the process by which a batch job, typically defined by Job Control Language (JCL), is submitted to th...
Job Log
A Job Log in z/OS is a comprehensive execution record generated for every batch job submitted to the system. It captures all messages, JCL statements,...
Job Management
Job Management in z/OS refers to the comprehensive process of controlling the lifecycle of batch jobs and started tasks, from their submission to thei...
Job Name
In the z/OS environment, a Job Name is a unique alphanumeric identifier assigned to a batch job or started task. It serves as the primary means for th...
Job Number
In z/OS, a **job number** is a unique identifier assigned by the Job Entry Subsystem (JES) to every batch job, started task (STC), and TSO user sessio...
Job Priority
Job Priority is a numerical value assigned to a batch job that determines its execution precedence and resource allocation within the z/OS Job Entry S...
Job Processing - Running jobs
Job processing, in the mainframe context, refers to the entire lifecycle of executing a batch job on z/OS, from its submission to its completion. It i...
Job Queue
A `Job Queue` in the z/OS environment is a sequential list, managed by the Job Entry Subsystem (JES), that holds batch jobs which have been submitted ...
Job Scheduler
A Job Scheduler in the z/OS environment is a specialized software component or product designed to automate, manage, and control the execution of batc...
Job Stream
A job stream, often referred to as a job flow or batch stream, is a predefined sequence of two or more `jobs` that are executed in a specific order on...
Job Library
While the term `Joblib` primarily refers to a Python library for parallel computing, in the context of IBM z/OS, a **Job Library** (often synonymous w...
Jobname
A `jobname` is a unique, 1-to-8 character identifier assigned to a batch job or a started task (STC) within the z/OS operating system. It serves as th...
JOE - Job Output Element
A Job Output Element (JOE) is an internal control block used by the Job Entry Subsystem (JES) in z/OS to manage and track the output data sets generat...
Join
In the context of IBM z/OS and relational databases like DB2 for z/OS, a `JOIN` is an SQL operation used to combine rows from two or more tables based...
Join Column / Matching Field
A join column, often referred to as a matching field, is a column or set of columns used to establish a logical relationship between two or more table...
Shared DASD
Shared DASD (Direct Access Storage Device) refers to a configuration where one or more physical DASD volumes or storage subsystems are concurrently ac...
Journal - Transaction log
A journal, often referred to as a transaction log, is a sequential, persistent record of changes made to data resources by transactions or application...
Journaling
In the mainframe context, journaling refers to the process of sequentially recording all changes made to data resources, such as files or database seg...
JP - Japan
In the context of IBM z/OS mainframes, "JP - Japan" primarily refers to the specific requirements and implementations for supporting the Japanese lang...
JPEG
JPEG (Joint Photographic Experts Group) is a widely adopted standard for lossy compression of digital images, primarily used for photographs due to it...
JRE - Java Runtime Environment
The Java Runtime Environment (JRE) on z/OS is a software package that provides the necessary components to run Java applications within the z/OS opera...
JS - JavaScript
JavaScript (JS) is a high-level, interpreted programming language primarily known for enabling interactive web pages and client-side web development. ...
JSAM - Job Summary Analysis Monitor
JSAM (Job Summary Analysis Monitor) is a utility or software product designed for the IBM z/OS environment to monitor, analyze, and report on the exec...
JSP - Java Server Pages
JSP (Java Server Pages) is a technology used to create dynamic web content by embedding Java code within HTML or XML pages. On IBM z/OS, JSPs are typi...
JSR - Jump to Subroutine
In the context of IBM mainframe assembly language (e.g., HLASM), `JSR` (Jump to Subroutine) is a common programming convention or a pseudo-instruction...
JTC - Job Transfer Control
Job Transfer Control (JTC) is a fundamental component within the Job Entry Subsystem (JES2 or JES3) on IBM z/OS that facilitates the movement of jobs ...
JTLS - Job Tracking and Location System
JTLS, or Job Tracking and Location System, is a utility or component within a z/OS environment designed to monitor, track, and report on the status an...
JTM - Job Transfer and Manipulation
JTM, or Job Transfer and Manipulation, refers to the capability within z/OS to transfer batch jobs, their associated input data, and their output data...
JTS - Java Transaction Service
The Java Transaction Service (JTS) is a standard specification for distributed transaction management in Java environments. It defines the interfaces ...
Julian Date - Day of year
A Julian Date, in the mainframe context, typically refers to a date format that represents the year and the sequential day within that year. It is com...
Branch Instruction
A branch instruction is a fundamental CPU instruction that alters the sequential flow of program execution by transferring control to a different, spe...
Jurisdiction - Authority Area
In the context of IBM z/OS, "Jurisdiction" or "Authority Area" refers to the precisely defined scope of control, responsibility, or access rights assi...
Justification
In the context of mainframe data processing, **justification** primarily refers to the alignment of data within a fixed-length field, dictating whethe...
Justify
In the mainframe context, **justification** refers to the alignment of data within a defined field or output area, typically to the left, right, or ce...
JVM - Java Virtual Machine
The Java Virtual Machine (JVM) on z/OS is a software layer that provides a runtime environment for executing Java bytecode. It enables Java applicatio...
K
K - Thousand or Kilobyte
In the mainframe and z/OS context, 'K' primarily serves as a unit suffix denoting either one thousand (1,000) or, more commonly, one kilobyte (1,024 b...
KB - Kilobyte
A Kilobyte (KB) is a standard unit of digital information storage, historically and commonly representing 1,024 bytes (2^10 bytes) in the context of m...
KBD - Keyboard
In the mainframe context, a Keyboard (KBD) refers to the primary input device associated with an IBM 3270 terminal or its software emulator. It is spe...
Kbps - Kilobits per second
Kbps, or Kilobits per second, is a standard unit of measurement for data transfer rates, representing 1,000 bits of data transmitted or received per s...
KBS - Knowledge Based System
A Knowledge Based System (KBS) on the mainframe is an artificial intelligence application designed to capture, store, and apply human expertise to sol...
KByte - Kilobyte
A Kilobyte (KB or KByte) is a unit of digital information storage or memory, conventionally representing 1,024 bytes (2^10 bytes) in the context of co...
KCS - Kernel Crash Dump System
The Kernel Crash Dump System (KCS) is a critical diagnostic facility within the z/OS operating system designed to automatically capture the state of t...
KD - Kernel Debugger
In the context of z/OS, the term "Kernel Debugger" does not refer to a single, dedicated product like it might in other operating systems. Instead, it...
KDS - Key Data Set
A Key Data Set (KDS) specifically refers to the **index component** of a VSAM Key-Sequenced Data Set (KSDS) on z/OS. It stores the primary keys of rec...
Kerberos
Kerberos is a network authentication protocol that provides strong authentication for client/server applications by using secret-key cryptography. In ...
Kernel - Operating system core
In the context of IBM z/OS, the term "kernel" is not explicitly used; instead, the core, privileged component of the operating system is referred to a...
Kernel Mode
In the context of IBM z/OS, **Kernel Mode** refers to a highly privileged execution state of the CPU where the operating system's core components and ...
Key
In the mainframe and z/OS context, a **key** is one or more contiguous fields within a record that uniquely identifies the record, determines its sequ...
Key Field
A Key Field, often referred to as an identifying field, is a specific data field or combination of fields within a record, segment, or row that unique...
Key Length
Key length refers to the number of bytes or characters that constitute a key field within a record or data structure. In mainframe systems, a key is a...
Key Range - Span of keys
In mainframe data management, a key range refers to a contiguous set of key values used to define a segment or partition of a larger data set or datab...
Key Sequence - Ordered by key
This refers to a method of organizing and accessing data records based on a specific key field within each record. In the mainframe context, it primar...
Key Sequenced Dataset - KSDS organization
A Key Sequenced Dataset (KSDS) is a type of VSAM (Virtual Storage Access Method) dataset that stores records in ascending order based on a unique key ...
Keyboard
In the context of IBM mainframe systems, a keyboard is the primary input device used by users to interact with the z/OS operating system and its appli...
Keyed
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S
System and Application Design
System and Application Design on the mainframe refers to the meticulous process of planning and structuring the architecture, components, interfaces, ...
V
VSAM
VSAM (Virtual Storage Access Method) is a high-performance, record-oriented access method used on IBM z/OS systems to organize, store, and retrieve da...
VSCR - Virtual Storage Constraint Relief
Virtual Storage Constraint Relief (VSCR) refers to a series of ongoing enhancements and design changes within z/OS and its associated subsystems (like...
VSM - Virtual Storage Management
Virtual Storage Management (VSM) is a core component of the z/OS operating system responsible for allocating, managing, and deallocating virtual stora...
VTL - Virtual Tape Library
A Virtual Tape Library (VTL) is a disk-based storage system that emulates traditional physical tape libraries and tape drives, presenting them as stan...
VTOC - Volume Table of Contents
The **Volume Table of Contents (VTOC)** is a critical data structure residing on every **Direct Access Storage Device (DASD)** volume in a z/OS enviro...
VTAM - Virtual Telecommunications Access Method
VTAM (Virtual Telecommunications Access Method) is a core IBM z/OS software component that manages communication between applications (like CICS, IMS,...
W
WLM - Workload Manager
Workload Manager (WLM) is a core component of IBM z/OS that dynamically manages system resources to achieve predefined business goals and service leve...
Work Area
In mainframe programming, particularly within COBOL, a **work area** refers to a temporary storage section within a program's memory used to hold data...
Working Set
In z/OS, the **working set** refers to the collection of virtual storage pages belonging to an active program or address space that are currently resi...
Workload
In the context of IBM z/OS, a workload represents the aggregate amount of processing tasks, transactions, batch jobs, and system overhead that a mainf...
Wraparound
In the context of IBM mainframe systems and z/OS, wraparound refers to the behavior where a counter, index, or data structure, upon reaching its maxim...
Write - Storing data to output
In the context of mainframe computing, a **write operation** refers to the process of transferring data from a program's internal memory (e.g., a COBO...
WTO - Write to Operator
WTO (Write To Operator) is a fundamental z/OS service that allows application programs, system components, and utilities to send messages directly to ...
WTOR - Write to Operator with Reply
WTOR (Write to Operator with Reply) is a type of message issued by the z/OS operating system or an application program that requires an explicit respo...
X
XCF - Cross-System Coupling Facility
XCF (Cross-System Coupling Facility) is a z/OS component that provides services for authorized programs to communicate and share data between multiple...
XES - Cross-System Extended Services
Cross-System Extended Services (XES) is a core component of z/OS that provides services for managing shared data and resources across multiple z/OS sy...
XML - Extensible Markup Language
XML (Extensible Markup Language) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and m...
XRC - Extended Remote Copy
XRC (Extended Remote Copy), now commonly referred to as **z/OS Global Mirror**, is an asynchronous remote data replication solution for IBM `DASD` (Di...
Z
Zap
In the mainframe context, a **Zap** refers to the direct, byte-level modification of executable program code (typically a load module) or data within ...
zFS - z/OS File System
zFS (z/OS File System) is a native, kernel-based hierarchical file system for z/OS that provides a UNIX-like file system interface and POSIX complianc...
z/OS
z/OS is IBM's flagship mainframe operating system, designed to run mission-critical, high-volume, and highly secure enterprise workloads. It is the di...
z/VM
z/VM is IBM's virtual machine operating system for the zSystems platform, functioning primarily as a Type 1 hypervisor. It enables the creation and ma...
z/VSE
z/VSE (Virtual Storage Extended) is an IBM mainframe operating system designed for efficient, cost-effective operation in smaller to mid-sized mainfra...
ZOWE
Zowe is an open-source framework that provides modern, standardized interfaces to interact with IBM z/OS. It aims to make the mainframe more accessibl...
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