MVS... a long history.

A history of IBM's most powerful and reliable operating system.

make-up by Thierry FALISSARD, updated on March 9, 2001

Warning : I am not the author of this text. It was written by Richard (Dick) Suko, who was, prior to his retirement, a senior technical staff member at IBM's Myers Corners Road facility in Poughkeepsie, NY. Throughout his career, Mr. Suko played a significant role in helping meet evolving product requirements, and has remained a vital resource to the industry.

In October 1999, Shmuel (Seymour J.) Metz brought some remarks and corrections to this history (they are italicized in the text).

In December 2000, Ray Saunders, a GOD (Grumpy Old Dinosaur) reminds us that something existed even before OS/360 !

Interesting historical document : Architecture of the IBM System/360, by Gene Amdahl.

MVS: Then and now.

Today, MVS is IBM's most powerful and reliable computer operating system. Over the years, MVS has been refined and honed, incorporating customer requirements, remaining attuned to new hardware and software developments, and expanding its capabilities to keep pace with changing directions in technology. The MVS of today is not the MVS of old. In fact, much of MVS has been rewritten, using state-of-the-art techniques which reflect new concepts and functions to ensure high levels of quality and availability.

MVS/ESA has a long and rich heritage. Its roots lie in OS/360, an IBM operating system developed in the 1960s. Whether you are a newcomer to MVS, or have been in data processing for 40 years, we hope you enjoy this retrospective.

'64 : OS/360.    '72 : OS/VS1 and OS/VS2. The debut of MVS.    '79 : MVS/370.

'81 : MVS/XA.    '88 : MVS/ESA.    '91 : the continuation of MVS/ESA.

The future.

Future directions point to MVS support of a parallel processing environment, providing significant improvements in data sharing and workload balancing.

With MVS/ESA, a high degree of scaleability has been achieved, moving from a uniprocessor environment through eight-way multiprocessing and Sysplex; from kilobytes of real storage to gigabytes of central and expanded storage. Additional processors are supported with efficient utilization ratios. MVS/ESA supports the full range of architectural features. Architecture-defined protection mechanisms range from low-address protection for MVS to subsystem storage protection for CICS. MVS/ESA defines virtual storage that reaches into terabytes. It has added sort instructions, DB2 sort-assist facility, a vector facility, a cryptographic feature and compression, data streaming channels, dynamic channel subsystems, ESCON channels, CTCs, a Sysplex Timer and more.

MVS/ESA has evolved into a highly sophisticated and reliable operating system - one which provides tremendous customer value and is continually responsive to customer needs. MVS/ESA has the quality, integrity and function, along with the responsiveness and the performance realization, required to run today's businesses. No other operating system matches it.

Application investments made in OS/360, OS/VS2, MVS/370, MVS/XA and earlier levels of MVS/ESA continue to work with today's MVS/ESA.

MVS will continue to enhance its offerings with the characteristics that have always been its strengths - and can help companies like yours meet the challenges of the '90s.

T.Falissard's note. Mr. Suko wrote this text in the beginning 90's. MVS/SP5 and Parallel Sysplex had not been unveiled by IBM. Today OpenEdition is called UNIX System Services. The future of MVS in the 2000's is deemed to be 64-bit addressing, e-business (Web enabling), more client-server and more Sysplex.

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