IPL unit_address LOADPARM where LOADPARM bytes contain:

bytes 1--4

5--6

7

8

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

￿ IODF DASD ￿ LOADxx ￿PROMPT FEAT. ￿ ALT NUCx ￿

￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿￿

IODF

LOADxx

prompt

nucleus

device

suffix

feature

suffix

number

 

 

 

See Managing Catalogs, SC26-4914, chapter 2. You must ensure that all OS/390 data sets required for IPL are cataloged in all catalogs that might be used as an alternate master catalog. Other than content, there is no difference between a user catalog and the master catalog. A catalog is the OS/390 master catalog by virtue of the fact that it was designated as such during IPL.

The master catalog must be on a volume that is mounted and available at all times. The master catalog should be password protected or secured via RACF. This is to insure that user data sets are not cataloged in the master catalog and to insure that end users cannot uncatalog critical system data sets.

Formerly, a single catalog could not serve as the master catalog for more than one system at a time. However, a master catalog could be accessed from another system as a user catalog.

You can now share a master catalog between multiple systems. See Managing Catalogs, SC26-4914, chapter 2.

With the introduction of MVS/SP 5.1.0, an installation that has multiple MVS images can share a master catalog and share an IPL volume among multiple MVS images. The system data sets, SYS1.LOGREC and SYS1.STGINDEX are no longer fixed named and unable to be shared. They can now be shared and specified by the installation. In addition, a system symbolic, &SYSNAME, was introduced and can be used as part of data set name specifications for some parameters in PARMLIB. When you use &SYSNAME, data set name specification becomes flexible and you do not need a separate parameter specification for each system in the sysplex.

For example, we can specify the following LOGREC=SYS1.LOGREC.&SYSNAME. The symbolic name, &SYSNAME can also be used in other PARMLIB parameter specifications. You can use &SYSNAME for IEASYSxx parameters VIODSN=, PAGE=, SWAP=, DUPLEX=, and NONVIO=. You can use &SYSNAME for SMFPRMxx parameters DSNAME= and SID=. Catalog if it has been connected to the second system¢s master catalog via the AMS ²IMPORT CONNECT² command.

5.6.3.2 OS/390 User Catalogs

User catalogs contain data set information for user data sets. They should be created as ICF catalogs. VSAM user catalogs may be accessed during the migration period, but should only be used if VSE access is required. They should be converted to ICF catalogs once the migration is over.

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IBM manual 3.2 OS/390 User Catalogs, LOADxx Prompt Nucleus Device Suffix Feature
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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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