procedures. Most will simply try to reproduce with the new OS/390 product what they were doing in VSE with or without assistance of a product. The challenge is to:

Understand how OS/390 works,

Understand how the OS/390 job scheduler or report manager is best used,

Define specific local implementation rules and guidelines (standards), and finally

Convert the existing VSE instructions and ways of doing things from VSE to OS/390.

An additional complication is that it is difficult to test the population of those products (at least for the report manager) in simulated production mode without disrupting or confusing the end-users. Test versions of application reports created under OS/390 cannot be sent to their future recipients using the OS/390 report manager without risking that they be taken as current VSE generated production versions. It is feasible to verify most of the automated daily job scheduling by simply running the OS/390 job scheduler in simulated production mode, although it is never easy to reproduce all actual production size executions and event triggered executions. But it becomes a real challenge to mimic lower frequencies such as weekly, biweekly, and monthly, especially when they are integrated to daily production. In any case, if those products are to be used in production under OS/390, they must be used when regression testing the converted applications.

It is atypical that the OS/390 job scheduler and report manager will be:

Populated once, just after the vendors basic education class

Changed partly or totally a few months later, after regression testing has identified a number of conceptual or implementation flaws

Adjusted one more time after switchover, once in OS/390.

This is because production control personnel are often ill prepared to perform this migration. Participation of hired consultants, experts with the OS/390 product implementation or an application analyst or technical support staff may be part of the solution.

The setup of a job scheduler and report manager may last three to four months and represent 10 to 15% of the total application conversion effort.

2.8 Cost Considerations

It is often thought that OS/390 will require more hardware and staff resources. While OS/390 may, in some cases, require more overhead and hence CPU, per unit of work, typically greater system throughput is achieved over that of the VSE environment. Due to enhanced systems management and automation capabilities it has been found that OS/390 staff requirements actually do not increase compared to VSE. In cases where staff increases have been seen, it has usually resulted from growth in system requirements. That is, application and end-user growth requirements has spawned the need for additional system resources. This need for additional system resources, then, sometimes requires additional human resource support.

While migration project cost projections will vary for each environment and customer, there are some basic cost elements that are common to all projects.

38VSE to OS/390 Migration Workbook

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IBM OS/390 manual Cost Considerations

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.