the beginning of staggered and overlapping testing. Online system testing may overlap batch unit testing.

32.5.7 System Testing

In system testing the goal is to go through the online applications and verify that the outputs from each operating system are similar. In the systems test phase each application is tested in more detail and each applications output is verified as being close to the production system.

Online

Online application tests continue with full-size application functional testing involving a joint effort of the conversion team, applications support staff and a few selected end users willing to cooperate. User exceptions are filtered and corrected by applications support. Test exceptions created by improper conversion are identified and passed over to the conversion team for resolution. Temporary manual by-pass corrections are applied to the OS/390 application, in order to quickly resume testing. But each conversion error is also fully analyzed (qualitative and quantitative analysis), and a permanent and global (all occurrences) solution is developed by refining the custom modification of the conversion tools, or by developing additional conversion tools. Additional mass or partial conversions generate new and correct OS/390 application material. Per design, the test of online transactions often requires the execution of batch jobs. Both batch and online tests are integrated at this point.

Batch

The objective of this task in batch is to execute the converted jobs in MVS to verify that they function as they did in VSE, and to correct software conversion errors or file migration errors that generate test exceptions.

Full size copies of the VSE production files are migrated to MVS, and in the process, the file migration procedure to be used later on at switchover, is tested.

In system testing you are testing the code more as an application. This is where JOB A feeds JOB B which feeds JOB C and so on. It may be general ledger or accounts payable. At this time a key task is ensuring that all the input and output are correct.

Batch application tests continue with full-size application functional testing involving a joint effort of the conversion team, production control and applications support staff. User exceptions are filtered and corrected by the production control or applications support. Test exceptions created by improper conversion are identified and passed over to the conversion team for resolution. Temporary manual by-pass corrections are applied to the OS/390 application, in order to quickly resume testing. But each conversion error is also fully analyzed (qualitative and quantitative analysis), and a permanent and global (all occurrences) solution is developed by refining the custom modification of the conversion tools, or by developing additional conversion tools. Additional mass or partial conversions generate new and correct OS/390 application material. Per design, the test of batch applications often requires the execution of online transactions. Both batch and online tests are integrated at this point.

One problem that can surface in this phase of testing is with data set definitions and the use of temporary data sets. A problem can surface when the data from

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IBM OS/390 manual System Testing, Online, Batch

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.