15.2.3.4 SPIE STAE

As user-program execution options they authorize PL/I to issue SPIE and STAE macros to intercept program checks and abends. It is possible with NOSPIE and NOSTAE to prevent this and in this case it is no longer certain that the management of errors will be handled by system ABEND or by an interruption handling program. This, therefore, allows an error routine to call PL/I modules and to continue to secure to itself the management of errors.

15.2.4 The EXEC and PROCESS Cards

It is possible to pass information to the PL/I compiler either by the EXEC or PROCESS statement. The PROCESS statement has the advantage of being processed by the PL/I compiler and therefore does not follow the OS JCL conventions. It can, as for all PL/I statements, be contained in more than one source program line and is not therefore limited in length. The parameter of the EXEC statement, on the other hand, is limited to a maximum of 100 characters. The format of the PROCESS statement is the same in MVS and DOS.

15.3 Linkages Between Languages

15.3.1 Linkages Supported

The linkages supported in MVS PL/I are those with COBOL, FORTRAN and Assembler. The support is obtained by specifying the necessary information in the PROC and ENTRY statements, refer to the respective ProgrammersGuides. In the case of Assembler, it is necessary to guard against modifying the contents of register 12 if PL/I is to intercept ABENDs or program checks. Modification of register 12 can cause relatively distracting messages such as:

ERROR IN PL/I ERROR HANDLER

This will occur if a program check or ABEND occurs in the Assembler subroutine at a time when R12 does not point to the PL/I control block expected by the PL/I error handler.

15.3.2 Linkages not Supported

The linkage with RPG II is supported in DOS PL/I. The MVS PL/I compiler does not support linkage with RPG II.

15.4 ENVIRONMENT Attributes

Most of the ENVIRONMENT options are no longer necessary in MVS, as they are required only at execution time and are therefore specified in the DCB parameter of the DD statement.

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IBM OS/390 manual Exec and Process Cards, Linkages Between Languages Linkages Supported, Linkages not Supported, Spie Stae

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.