Application Development & Test System

A system that is expected to stay up without disruption at least during ²normal working hours². Understand that any outages to this system will affect your applications conversion and testing activities. This logical image may eventually become your production OS/390 system when you cut-over.

Maintenance System The next version of operating system software, or next round of maintenance that will be rolled forward into production. (It is very important to use SMP/E to maintain your OS/390 system.)

This can double as your ªSystems Programmer Sandboxº for testing new operating functions or options that can be brought up and down as desired without worrying about disrupting other users.

This can also be your system on which operators can be trained without fear of reprisal should they do something wrong. This system can be re-IPLed during scheduled times to train operators on startup and shutdown procedures.

After your production cut-over to OS/390, you will also need a ªFall-Back Systemº for backup should the primary production system have too many problems to keep it up. This is different from a ªBackup systemº mentioned above, and may just be a copy of the SYSRES volumes and program libraries at the previous level of maintenance.

26.2 Test Systems in the Life of the Migration

You will need at least three S/390 images during this migration. Here is a simple example of how they can be used at different stages of the migration:

1Initial OS/390 System Installation, Tailoring, and Verification

During this phase, the test system is undergoing frequent changes and may have to be restarted often.

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿

VSE

￿

￿

OS/390

￿

￿

VSE

￿

￿

Production

￿

￿ Maintenance

￿

￿

Backup

￿

￿

 

￿

￿

(Sand-box)

￿

￿

 

￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

2Application Program, JCL, and Data Conversion

During this phase, the test system must be readily available for the programmers and others to make and test changes to the applications. You will also need a systems programming system for applying maintenance, and testing new or modified systems.

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿

VSE

￿

￿

OS/390

￿

￿OS/390 Maint. ￿

￿

Production

￿

￿ Application

￿

￿----- or -----￿

￿

 

￿

￿Conver′ n, Test￿

￿ VSE Backup ￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

420VSE to OS/390 Migration Workbook

Page 444
Image 444
IBM OS/390 manual Test Systems in the Life of the Migration, Production Maintenance Backup Sand-box

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.