19.2 Control Statements

DFSORT was designed to be functionally compatible with Sort/Merge at the control statement level, and for the most part, the control statement syntax of the two products is compatible. However, there are differences in some of the control statements that you will need to address. Here are the actions, if any, you should consider taking for each Sort/Merge control statement.

ALTSEQ: Can be used with no changes.

ANALYZE: Must be removed. DFSORT terminates if an ANALYZE statement is specified. Use DFSORTs dynamic allocation feature to allow DFSORT to automatically use the work space needed. Use SORTDIAG DD to produce diagnostic messages.

END: Can be used with no changes.

INCLUDE: Can be used with no changes.

INPFIL: Must be removed if the INPFIL statement is continued because DFSORT control statement errors can result. If the INPFIL statement is not continued, it can be used with no changes. DFSORT ignores all INPFIL operands. The equivalent information must be available from the input DD statements, input data set control blocks (DSCB) or catalog.

INREC: Can be used with no changes.

MERGE: Can be used with no changes.

MODS: Must be changed to use DFSORT syntax. User exit routines must be changed to use the DFSORT interfaces. See the DFSORT Application Programming Guide, SC33-4035 for complete details on the MODS statement and the interfaces for user exit routines.

OMIT: Can be used with no changes.

OPTION: Here are the actions, if any, you should consider taking for each

Sort/Merge OPTION operand:

ADDROUT: Must be removed. DFSORT terminates if this operand is specified. DFSORT does not support the use of direct-access addresses in output records. If you want to continue to include such addresses, you must write an E15 user exit to handle this.

CHALT: Can be used with no changes.

NOCHALT: Can be used with no changes.

DIAG: Can be used with no changes. DFSORT ignores DIAG. Use the SORTDIAG DD statement to obtain diagnostic messages.

NODIAG: Can be used with no changes. DFSORT ignores NODIAG.

DUMP: Must be removed. DFSORT terminates if this operand is specified. Specify a SYSUDUMP DD statement to obtain a dump.

NODUMP: Must be removed. DFSORT terminates if this operand is specified. Do not specify a SYSUDUMP DD statement to suppress a dump.

Chapter 19. SORT 377

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IBM OS/390 manual Control Statements

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.