ISR

Enhanced Definition

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 Primary Option Menu). It provides the primary interactive environment for developers to create, edit, browse, and manage source code, JCL, and other datasets. Less frequently, `ISR` can also stand for **Interrupt Service Routine**, a fundamental operating system component responsible for handling hardware and software interrupts.

- Primary Development Interface: Serves as the central hub for most interactive mainframe development tasks within the ISPF environment.
- Access to Core Utilities: Provides direct access to ISPF's Edit, Browse, and Utility functions, which are essential for managing files and code.
- Interactive Full-Screen Mode: Operates in a full-screen, character-based interface, allowing users to navigate menus, enter commands, and manipulate data.
- Customizable Environment: Users can personalize their ISR session through ISPF profiles, setting preferences for screen layout, key assignments (PF keys), and command aliases.
- Integration with TSO/E: Runs within the TSO/E (Time Sharing Option/Extensions) environment, enabling interactive user sessions on z/OS.

- Source Code Editing: Creating, modifying, and maintaining COBOL, PL/I, Assembler, REXX, and other programming language source files stored in PDS/PDSEs.
- JCL Management: Writing, editing, and submitting Job Control Language (JCL) for batch processing, as well as browsing job output.
- Dataset Management: Allocating new datasets, deleting existing ones, renaming, copying, and moving members within partitioned datasets.
- System File Browsing: Viewing system logs, spool files (SYSOUT), and other read-only datasets to monitor system activity or diagnose issues.
- Utility Execution: Invoking various ISPF utilities (e.g., Data Set List Utility, Compare,