IBM 7090/94 IBSYS

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Working stateHistoric
Initial release1960; 61 years ago (1960)
PlatformsIBM 7090 and IBM 7094
Preceded bySHARE Operating System

IBSYS is the discontinued tape-based operating system that IBM supplied with its IBM 709, IBM 7090 and IBM 7094 computers. A similar operating system (but with several significant differences), also called IBSYS, was provided with IBM 7040 and IBM 7044 computers. IBSYS was based on FORTRAN Monitor System (FMS) and (more likely) Bell Labs' "BESYS" rather than the SHARE Operating System. IBSYS directly supported several old language processors on the $EXECUTE card: 9PAC, FORTRAN and IBSFAP. Newer language processors ran under IBJOB.

IBSYS System Supervisor

IBSYS itself is a resident monitor program, that reads control card images placed between the decks of program and data cards of individual jobs. An IBSYS control card[a] begins with a "$" in column 1, immediately followed by a Control Name that selects the various IBSYS utility programs needed to set up and run the job. These card deck images are usually read from magnetic tapes prepared offline, not directly from the card reader.

IBJOB Processor

The IBJOB Processor is a subsystem that runs under the IBSYS System Supervisor. It reads control cards that request, e.g., compilation, execution. The languages supported include COBOL. Commercial Translator (COMTRAN), Fortran IV (IBFTC) and Macro Assembly Program (IBMAP).

See also

Further reading


  1. ^ The control cards included
    Call named subsystem, e.g., compiler, IBJOB, utility
    Reinitialize System Supervisor
    Call installation accounting routine
    Set up new job
    End a batch of jobs

External links

Edited: 2021-06-18 18:37:08