Your program must be in primary-space translation mode when you invoke the XPI. (For information about translation modes, see the IBM ESA/370 Principles of Operation manual.)

Notes:

1.You cannot use all of these calls at every global user exit point. You will find an indication of when these calls cannot be used both with the description of each function call, and in the list of exit points in the CICS Customization Guide.

Warning: These XPI calls are used to invoke CICS services; using them in the wrong exits causes unpredictable errors in your CICS system.

2.There is a restriction on using the XPI early during initialization. Do not start exit programs that use the XPI functions INQUIRE_MONITOR_DATA, MONITOR, TRANSACTION_DUMP, and WRITE_JOURNAL_DATA until the

second phase of the PLTPI. For further information about the PLTPI, refer to ²Writing initialization and shutdown programs² in the CICS Customization

Guide, SC33-1683.

3.These XPI functions are likely to cause the task executing the user exit program to lose control to another task while the XPI function is being executed. Therefore, the use of XPI functions must be very carefully considered as interrupting the flow of CICS functions could cause problems, such as lockouts, to occur.

For more information on tailoring CICS global and user exits review your CICS Customization Guide, SC33-1683.

Remember that CICS/ESA does not support macro-level programs. If you attempt to invoke programs with macro-level code and/or internal CICS addresses the following should result:

∙

∙

∙

CICS issues a warning message naming the offending program or transaction

CICS names the offending program or transaction and abends the offender CICS names the offending program or transaction and disables

Changes to the exit programming interface means that you will also need to make changes to global user exit programs. Still, you must reassemble all global exit programs. Plus, there are the following changes to be noted in your exit programs.

CSA and TCA addresses are withdrawn from DFHUEPAR.

The following API commands are not supported in global user exits:

Command

Exit points

 

 

EXEC CICS ABEND

All exits

 

 

EXEC CICS RETURN

All exits

 

 

All EXEC DLI

XRMIIN and XRMIOUT

 

 

All EXEC SQL

All exits

 

 

All CALL DLI

All exits

 

 

 

 

 

 

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IBM OS/390 manual Command Exit points, Exec Cics Abend, All exits, Exec Cics Return
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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.
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