Data Facility Storage Management Subsystem

Complementary functions of MVS/DFP and other individual products of the Data Facility family which, together with RACF, provide a system-managed, administrator-controlled storage environment.

Systems Resources Manager (SRM)

A system function that determines which address spaces should be given access to system resources (for example processor, storage, I/O), and the

rate at which each address space is allowed to consume resources. To a large degree, an installations control over the system is exercised through

the SRM; that is, via SRM tuning parameters.

Systems Management Facility (SMF)

A facility that gathers and records job accounting and other system-related information. By creating analysis and report routines, the collected information can be used for billing users, for analyzing workloads, and for profiling system resource usage.

Interactive Storage Management Facility (ISMF)

An interactive, online facility for defining and viewing the policy of how the Storage Management Subsystem manages auxiliary storage.

Time Sharing Option Extensions (TSO/E)

TSO/E provides interactive time sharing capabilities.

Interactive System Productivity Facility (ISPF)

Dialog manager required for interactive applications; for example ISPF/PDF, ISMF, and IPCS sessions.

Interactive System Productivity Facility/Program Development Facility (ISPF/PDF)

ISPF/PDF provides enhanced edit and browse facilities for aiding program development and library management functions.

Integrated Catalog Facility (ICF)

The name of the catalog in DFP that is a functional replacement for VSAM catalogs.

Interactive Problem Control System (IPCS)

An interactive, online facility used for diagnosing software failures; that is, dump viewing.

Message Processing Facility (MPF)

The facility that controls console message processing and message display. Message processing refers to message suppression, message retention, and the use of installation-supplied exits to control message processing.

Global Resource Serialization (GRS)

A component of MVS designed to protect the integrity of resources, particularly data sets on DASD volumes that are shared by two or more systems.

22VSE to OS/390 Migration Workbook

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IBM OS/390 manual ∙ Data Facility Storage Management Subsystem, ∙ Systems Resources Manager SRM

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.