Basic Operating System/360 (BOS/360)

Developer	IBM General Products Division (GPD)
Working state	Discontinued
Initial release	October 1965; 59 years ago (1965-10)
Marketing target	IBM mainframe computers
Available in	English
Platforms	System/360
License	Proprietary

Basic Operating System/360 (BOS/360) was an earlyIBM System/360operating system.

BOS was one of four System/360 Operating System versions developed by the IBM General Products Division (GPD) inEndicott, New York to fill a gap at the low end of the System/360 line when it became apparent that OS/360 was not able to run on the smallest systems.BPS (Basic Programming support) was designed to run on systems with a minimum of 8 KB of main storage and no disk. BOS was intended for disk systems with at least 8 KB and one2311 disk drive.^[1]DOS and TOS were developed from BOS for systems with at least 16 KB and either disks (DOS) ortape drives only (TOS).

BOS was released in October 1965, nearly two years before OS/360,^[2] thus BOS was the only disk based operating system available at launch for a machine that was marketed as disk based.

BOS consisted of the following components:

• Control programs:
  • Thesupervisor.
  • Job control capable of running jobs sequentially from the card reader.
  • TheIPL loader.
• System Service Programs:
  • TheLinkage Editor.
  • The Librarian, supporting a core-image library, and optionally a macro library and a relocatable library.
  • The "Load System Program," asysgen program to build a disk-resident BOS system from cards.
• IBM-supplied processing programs which could be installed with BOS:
  • Language translators, anAssembler and anRPG compiler. Compilers forFORTRAN IV andCOBOL were added later.
  • Autotest, a debugging aid.
  • Sort/Merge.
  • Utility programs for file-to-file copy between devices and formats.
  • Remote Job Entry allowing the BOS system to submit jobs to a remote System/360 and receive output.
• Data Management, consisting of supervisor support for PhysicalIOCS, and macros for Logical IOCS which could be incorporated into the user's processing programs.

TheIBM 1070 Process Communication Supervisor was a dedicatedprocess control system that ran as an extension under BOS "Relying on the BOS supervisor to handle ordinary physical and logical I/O operations (i. e., for cards, disk, etc.), the PC supervisor is specialized to the process control aspects of the user's program."^[3]

• Pugh, Emerson W.; Johnson, Lyle R.; Palmer, John H. (1991).IBM's 360 and Early 370 Systems, Cambridge : MIT Press. (pp. 321–345)

• IBM mainframe operating systems
• Discontinued operating systems
• Assembly language software
• 1965 software

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