OS/390 is an IBM

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...

for the

System/390 The IBM System/390 is a discontinued mainframe product family implementing the ESA/390, the fifth generation of the System/360 instruction set architecture. The first computers to use the ESA/390 were the Enterprise System/9000 (ES/9000 ...

IBM mainframe computers.

Overview

OS/390 was introduced in late 1995 in an effort to simplify the packaging and ordering for the key, entitled elements needed to complete a fully functional MVS operating system package. These elements included, but were not limited to: *Data Facility Storage Management Subsystem Data Facility Product (DFP)Provides access methods to enable I/O to, e.g., DASD subsystems, printers, Tape; provides utilities and program management * Job Entry Subsystem (JES)Provides the ability to submit batch work and manage print * IBM Communications ServerProvides

VTAM Virtual Telecommunications Access Method (VTAM) is the IBM subsystem that implements Systems Network Architecture (SNA) for mainframe environments. VTAM provides an application programming interface (API) for communication applications, and ...

and

TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...

communications protocols An additional benefit of the OS/390 packaging concept was to improve

reliability, availability and serviceability Reliability, availability and serviceability (RAS), also known as reliability, availability, and maintainability (RAM), is a computer hardware engineering term involving reliability engineering, high availability, and serviceability design. The ...

(RAS) for the operating system, as the number of different combinations of elements that a customer could order and run was drastically reduced. This reduced the overall time required for customers to test and deploy the operating system in their environments, as well as reducing the number of customer-reported problems (PMRs), errors ( APARs) and fixes ( PTFs) arising from the variances in element levels. In December 2001 IBM extended OS/390 to include support for 64-bit

zSeries IBM Z is a family name used by IBM for all of its z/Architecture mainframe computers. In July 2017, with another generation of products, the official family was changed to IBM Z from IBM z Systems; the IBM Z family now includes the newest mod ...

processors and added various other improvements, and the result is now named

z/OS z/OS is a 64-bit operating system for IBM z/Architecture mainframes, introduced by IBM in October 2000. It derives from and is the successor to OS/390, which in turn was preceded by a string of MVS versions.Starting with the earliest: * ...

. IBM ended support for the older OS/390-branded versions in late 2004.

References

IBM mainframe operating systems IBM ESA/390 operating systems 1995 software {{mainframe-compu-stub

Overview

See also

References