OS/VS1

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 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, or TSO), or a combination of both. However, OS/VS1 could, and often did, support interactive applications and users by running IBM's CICS transaction processing monitor as a job within one of its partitions.

Installation and modification of OS/VS1 is accomplished via IBM's System Generation (SYSGEN) process.

Job Entry Subsystem (JES)

Main article: Job Entry Subsystem 1

Job Entry Subsystem{{sfn | Planning

The job entry subsystem (JES) is a significant new feature of VS1. It replaces MFT readers, writers, job queue management, and HASP II. JES provides centralized management of system input data, system output data, and job queue processing. It handles local system input and system output streams, allocates and manages intermediate direct access storage for this data, interfaces with RES to handle remote. input and output streams, and manages allocation and processing of the job queue.{{sfn | Planning }}

Remote Entry Services (RES)

Remote Entry Services{{sfn | Features

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 and VM/VTAM Communications Network Application (VCNA).

IBM announced{{cite web the last BPE release, OS/VS1 Basic Programming Extensions Release 4, on September 15, 1983, with planned general availability in March 1984.

IBM announced{{cite web the end of functional enhancements to OS/VS1 in 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 Migration Aid. It allowed installations to run OS/VS1 and MVS/XA simultaneously on the same machine, as guests of a third systemVM/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{{cite web 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 Time Sharing Option (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.

References

;Features :{{cite book | access-date = November 15, 2025 ;Planning :{{cite book | access-date = November 15, 2025

Citation

References

1. "System/370 Model 148"".
2. (18 June 2024). "History of CICS Transaction Server".
3. During the 1970s, some universities ran the above combination during the day, and "went native" (no VM/CMS) at night, to run heavy batch work, e.g. administrative
4. Leavitt, Don. (1976-12-06). "Free Code Said to Manage IBM Control Block Usage". IDG Enterprise.
5. (1977-02-21). "TONE III". IDG Enterprise.