Talk:General Comprehensive Operating System

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The comment in this article "While GCOS is no longer in use..." is not accurate. Bull (Europe) still has several operating systems called GCOS. One, GCOS 8, is the direct descendent of the original GECOS. The company I work for still has numerous applications running in the GCOS-8 environment on machines owned and operated by Bull Services in Phoenix, AZ...Bob

Seconded. The aforementioned paragraph must be removed. The "GCOS is no longer in use" bit contradicts information found further in the article and the bit about pw_gecos is redundant with i. f. f. i. t. a. -- Paul Tergeist

There's also an open-source BIOS for the Nintendo Gamecube with this name.

I second (third?) the first paragraph. I worked in a GCOS shop from 1975 to 1992 and was active in the GCOS Community. There are a few other inaccuracies. To the best of my recollection from ancient software manuals, the acronyms GECOS and the other GE* acronyms (e.g. GEMAP) never stood for General Electric ... It was always "GEneral Comprehensive Operating Supervisor", "GEneral Macro Assembly Program", etc. Also, GCOS 8 was not a simple renaming of GCOS III for the DPS/8. GCOS 8 was the OS for the 'New System Architecture' which was a virtual memory architecture with segmentation and paging which the GCOS III systems did not have. Finally, If GECOS/GCOS owes anything to any IBM OS, it is only that the batch job control is vaguely reminiscent of that for the IBM 700/7000 series. -- Mark Sapiro

Can I suggest to move this page to its full name rather than GCOS? This acronym is also used by the climate community to designate the Global Climate Observing System, which has its own page. Users of Wikipedia searching for 'GCOS' should reach an appropriate disambiguation page. Michel M Verstraete 21:50, 10 May 2006 (UTC)

Operating System or Supervisor?[edit]

The GE 635 programming reference and the Honeywell GCOS manual for GCOS-III say "Supervisor". Can anyone cite a trustworthy source for the "S" in GCOS standing for "System"? Odam 07:55, 30 May 2006 (UTC)

If memory serves me it's actually General Comprehensive Operative Supervisor - I have some GCOS 6 Mod 400 (Level 6/DPS 6/DPS 6000) manuals somewhere and I'll see if I can find the full wording. Ian Dunster 18:13, 1 October 2006 (UTC)
I've had a look and AFAIKS nowhere does any of them give the full wording! - I did have a "GCOS 6 Mod 400 Programmmer's Pocket Guide" somewhere that I think DID give the full name but that's disappeared. Ian Dunster 09:44, 3 October 2006 (UTC)


The original 600 series systems were intended to compete with and replace IBM 7090 series systems which were also 36-bit systems. The GE 600 series systems employed a Base Address Register that allowed the OS to segment memory dynamically providing both efficiency and program isolation.

The GE 625 and 635 had block relocation. The term segment in this context should not be confused with a segmented virtual memory, where a single process has multiple segments and a virtual address contains either segment/offset or segment/page/offset designators. The version of GCOS that supported rings was for a more recent processor. Shmuel (Seymour J.) Metz Username:Chatul (talk) 19:36, 22 August 2013 (UTC)

Split into multiple articles?[edit]

Maybe it would be a good idea to split GCOS 7 and GCOS 8 into separate articles. All the IBM and Unisys mainframe systems have their own articles, and GCOS 7 and 8 are totally distinct systems (GCOS 7 has a Multics heritage, GCOS 8 is derived from the original GECOS.) It might also be a good idea to split out a Novascale article, covering both mainframe and commodity Novascale systems.

On another note, ACOS (a GCOS derivative) really needs its own article. Kiralexis (talk) 20:14, 27 June 2011 (UTC)


Should we capture some detail about the mini range? TPS6 was notable as one of the first transaction systems, and for its own language, Screenwrite. Campingcar (talk) 19:37, 15 July 2014 (UTC)

Sounds like it shoild have its own article. Peter Flass (talk) 21:48, 15 July 2014 (UTC)
The information doesn't belong here. Are you willing to write separate articles on TPS6 and the underlying hardware? IMHO they would be welcome. Shmuel (Seymour J.) Metz Username:Chatul (talk) 14:54, 16 July 2014 (UTC)
After a bit of research I see the hardware for GCOS 6 was a mini (16 or 18 bits?), so it was obviously a different beastie from GCOS 7/8. It would be nice to sort all this out. How similar was GCOS 6 to the others? Peter Flass (talk) 16:11, 16 July 2014 (UTC)
For what it's worth I created a tiny stub Honeywell Level 6 about the Level 6 and DPS 6, obviously to be filled in later, but I would suggest this as a place for anything you want to write about TPS 6. Peter Flass (talk) 15:02, 18 July 2014 (UTC)

GCOS is not like IBM 360[edit]

"Although GCOS has a basic architecture similar to that of the IBM 360 and earlier IBM 7090 Series, which was abandoned by IBM for the 360, and subsequent operating systems with which it competed, it was also heavily influenced by projects such as MEDINET, Multics, and WWMCCS, and has inherited a strong security structure in consequence."

I don't understand all of this sentence but it is too long, says too many things, and a number of things that are nonsensical. GCOS is an OS, IBM System/360 was a line of computers (that could run a variety of OSes).

The hardware underneath (original) GECOS and its logical successors had a family resemblance to the IBM 704 and its successors -- they were 36-bit systems. GECOS itself felt closer to IBSYS than OS/360.

I inferred that GE wished to catch IBM 7094 etc. users facing a serious discontinuity when IBM ended that line of hardware and software. The 7094 users were all doing scientific computing but little of that work was transferred to GE hardware. The success of the line came from elsewhere. UNIVAC's big machines were 36-bit too. As were DEC's.

The successor to the 7094 in some ways was the CDC-6600. It had 60-bit words. DHR (talk) —Preceding undated comment added 02:35, 14 July 2016 (UTC)

I understand the sentence, but as you noted, it's wrong. However, the last part is correct; GE enhanced GECOS (GCOS) in support of, e.g., WWMCCS, and part of that was based on Multics features.
While GECOS had similarities to IBSYS/IBJOB, the GE 625 et al looked nothing like the 7094, despite the identical word size.
The competitors to the 7094 were the CDC 3600, GE 625, UNIVAC 1107 and their big brothers; the CDC 6600 was well beyond the 7094 in capacity, cost and speed. It's baby brother the CDC 6400 might have been direct competition for the 7094. Shmuel (Seymour J.) Metz Username:Chatul (talk) 21:40, 26 July 2016 (UTC)