IBSYS is the discontinued tape based operating system that IBM supplied with its 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 SHARE Operating System.
IBSYS itself was really a basic monitor program, that read control card images placed between the decks of program and data cards of individual jobs. An IBSYS control card began with a "$" in column 1, immediately followed by a Control Name that selected the various IBSYS utility programs needed to set up and run the job. These card deck images were read from magnetic tapes, prepared offline, not usually directly from the punched card reader.
- Noble, A. S., Jr., "Design of an integrated programming and operating system", IBM Systems Journal, June 1963. "The present paper considers the underlying design concepts of IBSYS/IBJOB, an integrated programming and operating system. The historical background and over-all structure of the system are discussed. Flow of jobs through the IBJOB processor, as controlled by the monitor, is also described."
- "IBM 7090/7094 IBSYS Operating System Version 13 System Monitor (IBSYS)", Form C28-6248-7
- "IBM 7090/7094 IBSYS Operating System Version 13 IBJOB Processor", Form C28-6389-1
- "IBM 7090/7094 IBSYS Operating System Version 13 IBJOB Processor Debugging Package", Form C28-6393-2