19.3 Additional DFSORT/VSE Migration Considerations

DFSORT/VSE is based on and replaces Sort/Merge. It offers additional features not available in Sort/Merge. All of the migration considerations discussed previously for Sort/Merge apply to DFSORT/VSE as well. Migration considerations for additional features of DFSORT/VSE are discussed below.

19.3.1 Control Statements

OPTION: DFSORT/VSE has additional OPTION statement operands not found in Sort/Merge. Here are the actions, if any, you should consider taking for each such OPTION operand:

DSPSIZE: Can be used with no changes. However, since the OS/390 environment is considerably different from the VSE environment, you should determine if the DSPSIZE value specified is still appropriate as the maximum amount of data space to be used for dataspace sorting.

EQUALS: Can be used with no changes.

NOEQUALS: Can be used with no changes.

GVSIZE: Must be removed. DFSORT terminates if this operand is specified. GVSIZE has no meaning for DFSORT since OS/390 does not support GETVIS areas. By default, DFSORT uses virtual storage (above and below 16M virtual), dataspace sorting, hipersorting and work data sets, as appropriate.

GVSRANY: Must be removed. DFSORT terminates if this operand is specified. GVSRANY has no meaning for DFSORT since OS/390 does not support GETVIS areas.

GVSRLOW: Must be removed. DFSORT terminates if this operand is specified. GVSRLOW has no meaning for DFSORT since OS/390 does not support GETVIS areas.

LOCALE: Can be used with no changes.

SKIPREC: Can be used with no changes.

STOPAFT: Can be used with no changes.

STXIT: Must be removed. DFSORT terminates if this operand is specified. By default, DFSORT uses an ESTAE routine for abend recovery.

NOSTXIT: Must be removed. DFSORT terminates if this operand is specified.

Use the NOESTAE operand of the DEBUG control statement to suppress DFSORTs ESTAE routine for abend recovery.

WRKSEC: Must be removed. DFSORT terminates if this operand is specified. By default, DFSORT uses automatic secondary allocation for temporary JCL SORTWKnn data sets for which a secondary allocation amount is not specified.

NOWRKSEC: Can be used with no changes. However, since NOWRKSEC applies to SAM ESDS work files for Sort/Merge, but to temporary work files for DFSORT, you should determine if this operand should be kept or removed.

Y2PAST: Can be used with no changes.

OUTREC: DFSORT/VSE has additional OUTREC statement operands not found in Sort/Merge. Here are the actions, if any, you should consider taking for each such OUTREC operand:

Chapter 19. SORT 379

Page 403
Image 403
IBM OS/390 manual Additional DFSORT/VSE Migration Considerations

OS/390 specifications

IBM OS/390, a versatile operating system, was a cornerstone in enterprise environments and played a pivotal role in mainframe computing. Released in the mid-1990s, OS/390 combined the strengths of IBM's MVS (Multiple Virtual Storage) with new features and enhancements, targeting scalability, reliability, and performance in demanding business applications.

One of the key features of OS/390 was its robust support for multiple users and processes. The system allowed thousands of concurrent users to access applications and data, ensuring high availability and minimizing downtime—a critical requirement for many large organizations. This scalability was supported through various enhancements in memory management and processor scheduling, enabling optimal resource allocation across diverse workloads.

OS/390 was known for its superior workload management capabilities. The Workload Manager (WLM) component allowed administrators to define service policies, specifying how system resources would be allocated according to the priority of tasks. This ensured that critical business processes received the necessary resources while less critical tasks were managed more flexibly.

Another significant characteristic of OS/390 was its commitment to security. The operating system provided comprehensive security features, including user authentication, data encryption, and auditing capabilities. This focus on security was vital for organizations handling sensitive data, ensuring compliance with regulations and safeguarding against unauthorized access.

OS/390 also supported advanced technologies that facilitated integration and development. The system included features like the IBM CICS (Customer Information Control System) for transaction processing and IMS (Information Management System) for database management. These technologies allowed organizations to build robust, high-performance applications tailored to specific business needs.

The ease of network integration was another strength of OS/390. With the advent of the Internet and global connectivity, OS/390 systems could easily interface with various network protocols, enabling businesses to operate in a connected world. This inclusion paved the way for many organizations to expand their capabilities and offer new services, driving digital transformation.

In conclusion, IBM OS/390 represented a significant advancement in mainframe technology, combining scalability, security, and robust workload management. Its rich feature set and support for critical enterprise applications solidified its role as a vital component of many organizations' IT infrastructures, ensuring they could meet their operational challenges head-on while supporting future growth. As technology continues to evolve, the legacy of OS/390 remains influential in the realm of computing.