When the system date is on or after 1/1/2000, the following reason code will be issued:

²34 - Explanation: An attempt was made to open a VSAM catalog for use as a catalog. The request was denied.

Programmer Response: VSAM catalogs may not be used beginning Jan 1, 2000.²

Please note that CVOL support will also be removed effective 1/1/2000 but as yet no way to provide warning messages has been identified.

Customers running operating environments prior to DFSMS/MVS 1.4 who have not installed the appropriate maintenance will receive no warning message when processing VSAM catalogs and its entries, but are still subject to errors. Any customer failures resulting from attempts to process VSAM catalogs or CVOLs on OS/390 and MVS systems after December 31, 1999 will not be addressed by IBM service.

Information on how to convert VSAM catalogs and CVOLs to ICF catalogs can be found in chapter 9 of the DFSMS/MVS Managing Catalogs, SC26-4914.

Figure 8 (Part 2 of 2). Extract from WSC Flash 9741

5.6.3 OS/390 Catalog Management

5.6.3.1 OS/390 Master Catalog

OS/390 requires a master catalog in order to IPL. The master catalog cannot be disconnected and should not normally be ported to another system environment. The OS/390 master catalog should contain only:

∙

∙

∙

Alias definitions

catalog entries for system data sets

pointers to user catalogs

Certain system data sets must be cataloged in the master catalog in order to IPL. System data sets normally have data set names which start with ²SYS1² as their high-level data set name qualifier. Examples are SYS1.LINKLIB and SYS1.PROCLIB. See the OS/390 MVS System Data Set Definitions manual for the names and uses of OS/390 system data sets.

At IPL time the system locates the master catalog via the LOADxx member of the OS/390 system parameter data set, SYS1.PARMLIB. This member contains the master catalog¢s data set name, volume serial number, and device type.

If multiple LOADxx members exist (each with a unique ²xx² suffix), it is possible to choose an alternate master catalog at IPL time. Each LOADxx member would point to a different catalog. This might be done for testing or for backup purposes. The operator can specify the LOADxx member during IPL using the information contained in the following figure:

114VSE to OS/390 Migration Workbook

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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.
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