Table 32. Useful COBOL Publications

 

Form

Publication Title

Number

 

 

COBOL for OS/390 and VM Compiler and Run-Time Migration Guide

GC26-4764

 

 

COBOL for OS/390 and VM Language Reference

SC26-9046

 

 

COBOL for OS/390 and VM Programming Guide

SC26-9049

 

 

COBOL for VSE/ESA Migration Guide

GC26-8070

 

 

COBOL for VSE/ESA Programming Guide

SC26-8072

 

 

OS/390 Language Environment Migration Guide

SC28-1944

 

 

Taking Advantage of IBM Language Environment for VSE/ESA

SG24-4798

 

 

12.3 Converting from DOS/VS COBOL

If you are converting from VSE/SP or VSE/ESA 1.1, then you are running DOS/VS COBOL. In this case your source programs will have to be converted to COBOL for OS/390 and VM. Consider using a conversion aid such as COBOL and CICS Command Level Conversion Aid, running under OS/390, to help you.

If you are converting from VSE/ESA 1.2 or 1.3, then the conversion aid, CCCA/VSE, is available. CCCA/VSE converts your source code from DOS/VS COBOL to COBOL for VSE/ESA. COBOL for VSE/ESA source code is compatible with COBOL for OS/390 and VM, so you can then transfer your code to OS/390 for compilation and linkediting.

If you are converting from VSE/ESA 1.4 or VSE/ESA 2, then you also have the option to do a staged conversion. If you have COBOL for VSE/ESA and Language Environment for VSE/ESA installed on your system, you can convert your DOS/VS COBOL applications to COBOL for VSE/ESA and LE/VSE, and run them in your VSE system. When you are satisfied that they are running correctly, you can transfer the compiled object code to OS/390 for linkediting.

12.3.1 DOS/VS COBOL CICS Programs

OS/390 and COBOL for OS/390 and VM do not support CICS macro-level code. If you have any programs written in macro-level CICS you must convert them to command-level CICS.

COBOL for OS/390 and VM does not support BLL cells. If you use BLL cells in your CICS programs, you must modify the programs to remove them. CCCA will assist in making these changes.

When compiling DOS/VS COBOL CICS programs, the CICS translator did not require any particular option to indicate that the program being translated was DOS/VS COBOL. If you recompile your DOS/VS COBOL programs with COBOL for VSE/ESA, you must specify the CICS translator option COBOL2. If you recompile your DOS/VS COBOL programs under COBOL for OS/390 and VM, you must supply one of the CICS translator options COBOL3 or OOCOBOL.

252VSE to OS/390 Migration Workbook

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IBM OS/390 manual Converting from DOS/VS Cobol, 12.3.1 DOS/VS Cobol Cics Programs, Useful Cobol Publications

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.