# BOS/360

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**Basic Operating System/360** (**BOS/360**) was an early [IBM System/360](/source/IBM_System/360) [operating system](/source/Operating_system).

## Origin

BOS was one of four System/360 Operating System versions developed by the IBM General Products Division (GPD) in [Endicott, New York](/source/Endicott,_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)](/source/IBM_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 one [2311](/source/IBM_2311) disk drive.[1] [DOS and TOS](/source/DOS/360_and_successors) were developed from BOS for systems with at least 16 KB and either disks (DOS) or [tape drives](/source/Magnetic_tape) 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.

## Components

BOS consisted of the following components:

- Control programs: - The [supervisor](/source/Supervisory_program). - [Job control](/source/Job_Control_Language) capable of running jobs sequentially from the card reader. - The [IPL](/source/Initial_Program_Load#IBM_Initial_Program_Load) loader.
- System Service Programs: - The [Linkage Editor](/source/Linkage_editor). - The Librarian, supporting a core-image library, and optionally a macro library and a relocatable library. - The "Load System Program," a [sysgen](/source/Sysgen) program to build a disk-resident BOS system from cards.
- IBM-supplied processing programs which could be installed with BOS: - Language translators, an [Assembler](/source/Assembler_(computer_programming)#Assembler) and an [RPG](/source/IBM_RPG) compiler. Compilers for [FORTRAN IV](/source/FORTRAN_IV) and [COBOL](/source/COBOL) were added later. - Autotest, a debugging aid. - Sort/Merge. - Utility programs for file-to-file copy between devices and formats. - [Remote Job Entry](/source/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 Physical [IOCS](/source/IOCS), and macros for Logical IOCS which could be incorporated into the user's processing programs.

## IBM 1070 Process Communication Supervisor

The [IBM 1070](/source/IBM_1070) Process Communication Supervisor was a dedicated [process control system](/source/Industrial_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]

## References

1. IBM Corporation (Sep 1967). [*IBM System/360 Basic Operating System Programmer's Guide*](http://bitsavers.org/pdf/ibm/360/bos_bps/C24-3372-6_BOSpgmr_Sep67.pdf). Retrieved Jan 24, 2022.

1. Pugh, Emerson, et al. "IBM's 360 and Early 370 Systems". MIT Press, 1991, p. 331

1. IBM Corporation (1965). [*IBM System/360 Basic Programming Support and Basic Operating System/360 Programming Systems Summary (C24-3420-0).*](http://www.bitsavers.org/pdf/ibm/360/bos_bps/C24-3420-0_BPS_BOS_Programming_Systems_Summary_Aug65.pdf)

## Further reading

- Pugh, Emerson W.; Johnson, Lyle R.; Palmer, John H. (1991). [*IBM's 360 and Early 370 Systems*](https://books.google.com/books?id=MFGj_PT_clIC&q=IBM%27s+360), Cambridge : MIT Press. (pp. 321–345)

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Adapted from the Wikipedia article [BOS/360](https://en.wikipedia.org/wiki/BOS%2F360) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/BOS%2F360?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.