Operating System/Virtual Storage 1, or OS/VS1, is a discontinued

IBM mainframe IBM mainframes are large computer systems produced by IBM since 1952. During the 1960s and 1970s, IBM dominated the large computer market. Current mainframe computers in IBM's line of business computers are developments of the basic design of th ...

computer

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

designed to be run on IBM

System/370 The IBM System/370 (S/370) is a model range of IBM mainframe computers announced on June 30, 1970, as the successors to the System/360 family. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path ...

hardware. It was the successor to the Multiprogramming with a Fixed number of Tasks (MFT) option of

System/360 The IBM System/360 (S/360) is a family of mainframe computer systems that was announced by IBM on April 7, 1964, and delivered between 1965 and 1978. It was the first family of computers designed to cover both commercial and scientific applica ...

's operating system

OS/360 OS/360, officially known as IBM System/360 Operating System, is a discontinued batch processing operating system developed by IBM for their then-new System/360 mainframe computer, announced in 1964; it was influenced by the earlier IBSYS/IBJOB ...

. OS/VS1, in comparison to its predecessor, supported

virtual memory In computing, virtual memory, or virtual storage is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very ...

(then called ''virtual storage''). OS/VS1 was generally available during the 1970s and 1980s, and it is no longer supported by IBM.

Description

OS/VS1 was OS/360 MFT II with a single virtual address space; by comparison, OS/VS2 SVS was OS/360 MVT with a single virtual address space. OS/VS1 was often installed on mid-range IBM mainframe systems, such as the System/370 Model 145 and, later, the System/370 Model 148. OS/VS1 was intended to manage a medium-sized work load (for the 1970s) consisting only of

batch processing Computerized batch processing is a method of running software programs called jobs in batches automatically. While users are required to submit the jobs, no other interaction by the user is required to process the batch. Batches may automatically ...

applications, running within a fixed number of operating system partitions via the batch job management system Job Entry Subsystem 1 (JES1). 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 Time Sharing Option (TSO) is an interactive time-sharing environment for IBM mainframe operating systems, including OS/360 MVT, OS/VS2 (SVS), MVS, OS/390, and z/OS. Use In computing, time-sharing is a design technique that allows many peop ...

, or TSO), or a combination of both. However, OS/VS1 could, and often did, support interactive applications and users by running IBM's

CICS IBM CICS (Customer Information Control System) is a family of mixed-language application servers that provide online transaction management and connectivity for applications on IBM mainframe systems under z/OS and z/VSE. CICS family products ...

transaction processing monitor as a job within one of its partitions. Installation and modification of OS/VS1 was accomplished via IBM's cumbersome

System Generation In computing system generation or sysgen is the process of creating a particular unique instance of an operating system by combining user-specified options and parameters with manufacturer-supplied general-purpose program code to produce an oper ...

(SYSGEN) process.

Remote Entry Services (RES)

OS/VS1 included a replacement for OS/360 RJE. It allowed submission and retrieval of jobs by 2770, 2780 and 3780 terminals and by workstation programs included with OS/VS1 for, e.g., 1130. RES included Remote Terminal Access Method and a closer integration with Job Management than what RJE had.

IBM upgrades

OS/VS1 went through seven product releases. IBM enhanced OS/VS1 Release 7 with four releases of the IBM OS/VS1 Basic Programming Extensions (BPE), product 5662-257. BPE provides support for new 1980s hardware, such as 3380 Direct Access Storage, and for VM handshaking between

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 co ...

and VM/VTAM Communications Network Application (VCNA). IBM announced the last BPE release, OS/VS1 Basic Programming Extensions Release 4, on September 15, 1983, with planned general availability in March 1984. IBM announced the end of functional enhancements to OS/VS1 in 1984. IBM recommended OS/VS1 installations migrate to

MVS/370 Multiple Virtual Storage, more commonly called MVS, was the most commonly used operating system on the System/370 and System/390 IBM mainframe computers. IBM developed MVS, along with OS/VS1 and SVS, as a successor to OS/360. It is unrela ...

or MVS/XA. To assist with the migration to MVS/XA, IBM made the VM/XA Migration 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. On January 24, 1989, IBM announced the intention to withdraw OS/VS1 and OS/VS1 BPE from marketing effective April 24, 1989, and to discontinue service effective February 28, 1990.

Time-sharing

Although IBM's

(TSO) required VS2, customers with a 370/145 or 370/148 had other time-sharing options.
One combination was VM/CMS for time sharing, and a guest "machine" running OS/360 MFT II for batch.

Conversational Remote Job Entry

Optional component of OS/360 MFT II, OS/360 MVT and OS/VS1, CRJE allowed the user at a line-mode terminal to edit text datasets, submit jobs and access job output.

TONE for VS1

A non-IBM time-sharing product named TONE (TSO-like, for VS1 / VS ONE) was marketed by Tone Software Co.the p. 72 ad from the Feb. 21, 1977 issue of Computerworld, can be found at https://books.google.com/books?id=LD44Qbu9AsUC&pg=PA72&lpg=PA72 and the headline says "The ONLY ''COMPLETE'' TIME SHARING SYSTEM FOR VS1"