12.4.4.1 Program Termination

There are three COBOL program termination statements:

∙

∙

∙

EXIT PROGRAM GOBACK STOP RUN

There are some differences in the effect of these statements between DOS/VS COBOL and COBOL for OS/390 and VM. Table 33 gives a comparison of the behavior of these COBOL program termination statements, for DOS/VS COBOL and COBOL for OS/390 and VM.

Table 33. Action of COBOL Program Termination Statements

Statement

 

DOS/VS COBOL

COBOL for OS/390

 

 

 

and VM

 

 

 

 

EXIT PROGRAM

Main

No effect

No effect

 

Program

 

 

 

 

 

 

 

Subprogram

Return to calling

Return to calling

 

 

program

program

 

 

 

 

GOBACK

Main

Abnormal job

Return to calling

 

program

termination

program (may be

 

 

 

system and cause the

 

 

 

application to end)

 

 

 

 

 

Subprogram

Return to calling

Return to calling

 

 

program

program

 

 

 

 

STOP RUN

Main

Return to system and

Return to calling

 

program

cause end of job step

program (may be

 

 

(EOJ)

system and cause the

 

 

 

application to end)

 

 

 

 

 

Subprogram

Return to system and

Return directly to

 

 

cause end of job step

calling program (may

 

 

(EOJ)

be system and cause

 

 

 

the application to end)

 

 

 

 

12.4.5 File Handling Considerations

This section discusses some of the differences in file processing between

DOS/VS COBOL and COBOL for OS/390 and VM.

12.4.5.1 File Status Codes

Many of the file status codes returned from file processing differ between DOS/VS COBOL and COBOL for OS/390 and VM. These differences and changes are summarized in the COBOL for VSE/ESA Migration Guide and the COBOL for OS/390 and VM Compiler and Run-Time Migration Guide. You should review the relevant sections of these publications carefully.

In particular, in the case of VSAM files, you will now need to refer to the VSAM feedback codes as well as the file status code, to determine the exact nature of the reported condition.

Chapter 12. COBOL 257

Page 280 Page 282
Page 281
Image 281
IBM OS/390 manual File Handling Considerations, Program Termination, File Status Codes, Exit Program Goback Stop RUN
Page 280 Page 282

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.
Top Page Image Contents