32.1.2 Prerequisites

There are two key requirements that need to be satisfied before embarking on a migration:

1.The source code must be available for your applications. If the source code does not exist then it must be rebuilt.

2.A method to transfer the source code to the OS/390 system.

32.1.3Recommendations

The following are recommendations that either apply to all phases of your migration or are not specific to any phase.

32.1.3.1 Project Management

In some cases it may make sense to hire contractors, temporary personnel or a service provider to perform tasks that will only be performed once and do not provide long term payback to the installation. These one time tasks may include project management, specific conversion activities and use of project specific tools. There are many tasks to consider during a migration. Careful consideration should be given to knowing the skills that are available to the project, the requirements for systems programming, other projects that are planned or in progress, and how augmenting these skills and personnel may or may not make sense.

32.1.3.2 Take Advantage of Conversion Tools and Automation

Executing a migration with a mass conversion tool and automated processes can reduce both the time and people required to migrate from VSE to OS/390. Where it is not a large task to convert three programs and two strings of JCL, it is a large and difficult task to increase the scope by one thousand and perform the same conversion.

The automation provided by the use of a mass conversion tool is unique. After an extensive period of analysis, which includes running both pilot conversions and dummy conversions, you can, in a final mass conversion, convert all of your VSE applications to MVS in a single automated process.

32.1.3.3 Manuals

The MVS Migration System - Planning Guide and the MVS Migration System - General Information Manual are key publications and should be among the first manuals ordered when planning or investigating a migration.

32.1.3.4 Secure OS/390 Skills

The key benefits of having experienced production or systems programmer skills are with the installation of and running the new system. It takes time to learn and become comfortable in the OS/390 environment. An additional benefit of having an experienced OS/390 systems programmer on site, whether permanent or temporary, is through determining what the new system will look like by defining standards and naming conventions.

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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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