and parameters), and library members for control cards. This is because many of the VSE names are syntactically incorrect under OS/390. But the conversion of in-house developed applications doesn¢t require changing any of the names associated with the source code. In fact, it is recommended to leave the program, entry-point, copybook, code include and DD names unchanged to avoid confusing application support personnel.

The process of developing standards includes striking a balance between the conventions and familiarity of the VSE system and adopting durable and usable standards for the future OS/390 system. Follow local conventions wherever possible. Operators are used to particular names of data sets. Maintaining these wherever possible will make the transition easier.

32.4.4 Phase 2: Conversion Specifications

The project-specific conversion requirements are determined and documented during the specifications phase. The specifications phase, which begins with a

²clean² supply of the conversion inventory (source code and JCL), is typically completed in two to four months. The specification tasks include:

∙

∙

Developing a project plan

Educating the conversion project team to the conversion approach and to the project plan

∙Installing the conversion tools and performing a preliminary tailoring to local conditions

∙

∙

Studying the VSE source production environment

Defining the OS/390 target production environment, including OS/390 standards and naming conventions

∙Performing a pilot conversion of a subset of the conversion inventory before custom modifying the conversion tools

∙

∙

Identifying conversion issues and source code positioning activities

Designing automated conversion solutions, based on custom modification of the conversion tools, or development of additional ad-hoc conversion software

∙Conducting specifications meetings with technical representatives of VSE and OS/390 operations, technical support, and applications development

The site¢s specific conversion requirements are determined and documented by analyzing the VSE source material, designing OS/390 target material that complies with the selected OS/390 production standards, and designing the conversion paths (program translation, JCL conversion, and file migration).

This process comprises knowing what software will be replaced and what standards will be used in OS/390. It is recommended that DFSMS based naming standards be used in the design of the MVS target system. These must comply with the installation¢s standards and operations procedures for the MVS target production.

The Specifications phase is complete when the conversion specifications have been developed and approved by operations, technical support and applications development.

Chapter 32. Conversion Process 499

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IBM OS/390 manual Phase 2 Conversion Specifications
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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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