OS/VS1
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Operating System/Virtual Storage 1, or OS/VS1, was an IBM mainframe computer operating system designed to be run on IBM System/370 hardware. It was the successor to the IBM System/360 operating system OS/360 MFT (Multiprogramming with a Fixed number of Tasks). Unlike OS/360 MFT, OS/VS1 supported the management of virtual storage (also known as virtual memory).
OS/VS1 was only generally available from IBM during the 1970s and 1980s. It is no longer supported by IBM.
OS/VS1 was intended to manage a medium-sized work load (for the 1970s) consisting only of batch applications. This was in contrast to OS/VS2 which was intended to handle larger work loads consisting of batch applications, online interactive users (using the Time Sharing Option, TSO), or a combination of both.
OS/VS1 used the batch job management system Job Entry Subsystem 1 (JES1).
OS/VS1 went through seven product releases. OS/VS1 Release 7 was enhanced by four release of the IBM OS/VS1 Basic Programming Extensions (BPE) product. BPE provided support for new 1980s hardware, such as 3380 DASD (Direct Access Storage Device, IBM disk data storage devices).
The last OS/VS1 product release, OS/VS1 Basic Programming Extensions Release 4, was announced by IBM in 1983 for general availability in March 1984 (OS/VS1 BPE Release 4, product 5662-257, announcement letter 283-266, 15 September 1983).
IBM announced the end of functional enhancements to OS/VS1 in 1984 (OS/VS1 Consolidated Stabilization Statement, product 5652-VS1, announcement letter 284-086, 23 February 1984).
IBM recommended OS/VS1 installations migrate to MVS/370 or MVS/XA. To assist with the migration to MVS/XA, IBM made the VM/XA Mirgration Aid available. It allowed installations to run OS/VS1 and MVS/XA simultaneously on the same machine, so that the new MVS/XA system could be tested while the old production OS/VS1 system was still in use.
In a press release, in 2005, IBM claimed that it was the "first in the industry to virtualize a 'mainstream' operating system with OS/VS1 in 1972" (IBM press release concerning storage virtualization).
[edit] References to OS/VS1
- The job entry subsystem of OS/VS1, by J. H. Baily, J. A. Howard, and T. J. Szczygielski, IBM Systems Journal, Volume 13 (1974), No 3, Page 253 (The OS/V1 job entry subsystem was named JES1)
