about the same after switchover, with MVS showing a couple of percentage points higher.

Since the workload at this installation is not the typical online on prime shift and batch on second and third, it was not as easy to make comparisons on a batch window length. Overall it appeared that throughput was much better. There were other performance benefits realized. A good example was a large database that affected VSE performance could only be reorganized (to improve performance) on holiday weekends because of the many hours it took to perform the reorganization. Under MVS this reorganization time was cut by two thirds allowing this function to be performed on a more regular basis. This reduction in time was attributed to the better throughput of MVS and in the internal design of the MVS version of the ISV database manager.

34.7 Benefits

Other than the performance benefits mentioned above there were many other benefits realized by going to MVS. As new business comes along MVS is able to absorb the workload without many of the problems previously encountered by the I/S staff when they had to try to ²fit² this into the VSE environment. Examples of this are the ability to connect new NJE customers to one line using SNI as opposed to multidrop lines for 3270 access and a point to point bisync NJE line. When new business dictated more DASD, there was flexibility to go with the latest RVA DASD and not worry about operating system support issues. There is also the flexibility to grow the processor horizontally or vertically, which ever is more cost effective or quickest in order to take on new business. Even more important in this high availability environment where unscheduled VSE IPLs were frequent, MVS has run over a year without an unscheduled IPL.

532VSE to OS/390 Migration Workbook

Page 556
Image 556
IBM OS/390 manual Benefits

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.