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 System/360's operating system MFT (Multiprogramming with a Fixed number of Tasks), a variant of OS/360. OS/VS1, in comparison to its predecessor, was supporting virtual memory (then called virtual storage)[1]

OS/VS1 was generally available during the 1970s and 1980s, and 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 processing 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 was OS/MFT with a single virtual address space; OS/VS2 SVS was OS/MVT with a single virtual address space.

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 fourth release of the IBM OS/VS1 Basic Programming Extensions (BPE) product. BPE provided support for new 1980s hardware, such as 3380 DASD (disk).

The last OS/VS1 product release, OS/VS1 Basic Programming Extensions (BPE) Release 4, was announced by IBM in 1983 for general availability in March 1984 (product 5662-257, announcement letter 283-266, 15 September 1983).

IBM announced the end of functional enhancements to OS/VS1 in 1984.[2] 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. It allowed installations to run OS/VS1 and MVS/XA simultaneously on the same machine, as guests of a third system - VM/XA. This way, the new MVS/XA system could be tested while the old production OS/VS1 system was still in use.

[edit] References

  1. ^ IBM press release concerning memory virtualization from 2005
  2. ^ OS/VS1 Consolidated Stabilization Statement, product 5652-VS1, announcement letter 284-086, 23 February 1984