Conversion

Enhanced Definition

Key Characteristics

- Data Type Transformation: Involves changing data representation, such as converting EBCDIC to ASCII for data exchange with distributed systems, or transforming packed decimal to zoned decimal within COBOL programs or utilities.
- Character Set Handling: A critical aspect on z/OS, as most native data is EBCDIC, requiring careful conversion to ASCII (and vice-versa) when interacting with non-mainframe platforms. This often uses iconv services or specific utility parameters.
- Program or Application Migration: Can involve upgrading COBOL programs from an older standard to a newer one, migrating Assembler routines to COBOL, or even re-platforming applications from CICS to a distributed environment.
- System Upgrades: Refers to the process of migrating an entire z/OS operating system to a newer version, which often entails converting system datasets, configurations, and ensuring compatibility with installed software.
- Tool-Assisted: Often relies on specialized utilities like DFSORT, IDCAMS, DFSMSdss, ADRDSSU, or custom COBOL/Assembler programs for data conversion, and vendor tools for application or system migrations.
- Complexity and Risk: Conversions can be highly complex, requiring extensive planning, testing, and validation to ensure data integrity, application functionality, and minimal downtime, especially for critical production systems.

Use Cases

- Data Exchange: Converting EBCDIC flat files or database extracts to ASCII CSV or XML formats for consumption by Windows or Linux applications.
- Database Schema Changes: Reorganizing and converting data within DB2 or IMS databases due to schema modifications, table consolidations, or data type changes.
- Application Modernization: Migrating legacy COBOL applications from an older compiler version to a newer one, or adapting them to use modern features like DB2 stored procedures or CICS web services.
- Operating System Upgrade: Performing an in-place or parallel conversion to upgrade a z/OS system from, for example, z/OS V2.3 to z/OS V2.5, requiring conversion of system datasets and configuration files.
- Data Archiving/Reporting: Converting transaction data from its operational format into a standardized format suitable for long-term archiving, business intelligence reporting, or data warehousing.

Related Concepts

Conversion is intrinsically linked to data types, character sets (EBCDIC, ASCII), and data representation on the mainframe. It heavily utilizes JCL for executing conversion utilities and COBOL for programmatic data manipulation. It's a fundamental aspect of application modernization, system upgrades, and data integration strategies, often involving database systems like DB2 and IMS, and transaction managers like CICS.

Best Practices:

Thorough Planning and Analysis: Define the scope, source, target, and transformation rules explicitly. Understand data characteristics, dependencies, and potential impacts before starting.