within the data set name so that ACS Routines can easily ascertain one piece of data from another. The only alternative to this is to place a very restrictive convention on the qualifiers that can be specified.

For example, you could break down the table space name by having positional characters represent different levels of qualification for the data. The following is one possibility:

first character:

P --

production, T

-- test

 

second character:

R -- report, I --

intermediate file, M --

master DB

third character:

W

-- weekly, D --

daily, M -- monthly

 

fourth-eighth characters: table space name

Until this restrictive naming convention is lifted, the only other alternative is to use the available free characters to distinguish the data within the database application.

C.4.4 Generation Data Sets

The notion of a GDG (Generation Data Group) is that for a given name, say

²A.B.C² there could be many generations. Each generation data set (GDS) would have the following name form:

A.B.C.GnnnnV00

where:

nnnn = next number in sequence (may wrap around)

The only naming convention difference here is that the application loses one level of qualification, mainly the lowest level. Other than that, there is no real distinction between GDSs and other data set names. It is generally not a good idea, however, to use the generation to indicate a different type of data; for example, the idea of the ² + 1 ² version being a report, the ² + 2 ² version being an intermediate file. The first portion of the name should state what the data is and the generation should represent a later level or generation of that data. A better idea would be to have a separate GDG for reports, intermediate files and so on.

Appendix C. DFSMS Naming Conventions 551

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Image 575
IBM OS/390 manual Generation Data Sets, C.GnnnnV00

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.