Sizing the Effort, Introduction to Sizing

Chapter 2. Sizing the Effort

This chapter discusses the following topics:

2.1, Introduction to Sizing

2.2, OS/390 Components/Products/Subsystems

2.3, What Changes Between VSE and OS/390?

2.4, Who is Affected by This Migration?

2.5, Approaches to Migration

2.6, Educational Requirements

2.7, Scope of Work and Challenges

2.8, Cost Considerations

2.1 Introduction to Sizing

When undertaking a project such as migrating from VSE to OS/390 attention always turns to how much effort is really involved. The sizing effort attempts to get a fairly reasonable handle on the amount of effort and resources needed for such a project. It is desired to be able to estimate with some degree of confidence the human, system and financial resource requirements. This chapter will discuss some of the key migration activities and issues, highlighting the considerations that will affect the scope and size of this project. We will first define two terms that are often used throughout this publication, migration and conversion.

Migration is the process which takes the data processing workload, and operations from the VSE environment to the OS/390 environment. This includes a planning phase, a preparation phase, a conversion phase and a production implementation phase.

Conversion is the process within the migration where programs, data, and JCL are converted, tested, and cut over to production in the OS/390 environment.

2.1.1 Defining the Migration Project Objectives

Typical migration project objectives for an OS/390 migration project include a combination of operational needs and cost/benefit requirements.

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End-user transparency

Minimal disruption of operations and applications support

No overlap of dual VSE and OS/390 operations

Standardized and automated OS/390 applications fit for automated OS/390 operations

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.

IBM OS/390 Sizing the Effort, Introduction to Sizing, Defining the Migration Project Objectives

Models: OS/390

Chapter 2. Sizing the Effort

2.1 Introduction to Sizing

2.1.1 Defining the Migration Project Objectives

OS/390 specifications