Source : Free On-Line Dictionary of Computing

GCOS
     
         /jee'kohs/ An {operating system} developed
        by {General Electric} from 1962; originally called GECOS (the
        General Electric Comprehensive Operating System).
     
        The GECOS-II operating system was developed by {General
        Electric} for the 36-bit {GE-635} in 1962-1964.  Contrary to
        rumour, GECOS was not cloned from {System/360} [{DOS/360}?] -
        the GE-635 architecture was very different from the {IBM 360}
        and GECOS was more ambitious than DOS/360.
     
        GE Information Service Divsion developed a large special
        multi-computer system that was not publicised because they did
        not wish {time sharing} customers to challenge their bills.
        Although GE ISD was marketing {DTSS} - the first commercial
        time sharing system - GE Computer Division had no license from
        Dartmouth and GE-ISD to market it to external customers, so
        they designed a time-sharing system to sell as a standard part
        of GECOS-III, which replaced GECOS-II in 1967.  GECOS TSS was
        more general purpose than DTSS, it was more a programmer's
        tool (program editing, e-mail on a single system) than a BASIC
        TSS.
     
        The {GE-645}, a modified 635 built by the same people, was
        selected by {MIT} and {Bell} for the {Multics} project.
        Multics' infancy was as painful as any infancy.  Bell pulled
        out in 1969 and later produced {Unix}.
     
        After the buy-out of GE's computer division by {Honeywell},
        GECOS-III was renamed GCOS-3 (General Comprehensive Operating
        System).  Other OS groups at Honeywell began referring to it
        as "God's Chosen Operating System", allegedly in reaction to
        the GCOS crowd's uninformed and snotty attitude about the
        superiority of their product.  [Can anyone confirm this?]
        GCOS won and this led in the orphaning and eventual death of
        Honeywell {Multics}.
     
        Honeywell also decided to launch a new product line called
        Level64, and later DPS-7.  It was decided to mainatin, at
        least temporarily, the 36-bit machine as top of the line,
        because GCOS-3 was so successfull in the 1970s.  The plan in
        1972-1973 was that GCOS-3 and Multics should converge.  This
        plan was killed by Honeywell management in 1973 for lack of
        resources and the inability of Multics, lacking {databases}
        and {transaction processing}, to act as a business operating
        system without a substantial reinvestment.
     
        The name "GCOS" was extended to all Honeywell-marketed product
        lines and GCOS-64, a completely different 32-bit operating
        system, significanctly inspired by Multics, was designed in
        France and Boston.  GCOS-62, another different 32-bit low-end
        DOS level was designed in Italy.  GCOS-61 represented a new
        version of a small system made in France and the new DPS-6
        16-bit {minicomputer} line got GCOS-6.
     
        When the intended merge between GCOS-3 and Multics failed, the
        Phoenix designers had in mind a big upgrade of the
        architecture to introduce {segmentation} and {capabilities}.
        GCOS-3 was renamed GCOS-8, well before it started to use the
        new features which were introduced in next generation
        hardware.
     
        The GCOS licenses were sold to the Japanese companies {NEC}
        and {Toshiba} who developed the Honeywell products, including
        GCOS, much further, surpassing the {IBM 3090} and {IBM 390}.
     
        When Honeywell decided in 1984 to get its top of the range
        machines from NEC, they considered running Multics on them but
        the Multics market was considered too small.  Due to the
        difficulty of porting the ancient Multics code they considered
        modifying the NEC hardware to support the Multics compilers.
     
        GCOS3 featured a good {Codasyl} {database} called IDS
        (Integrated Data Store) that was the model for the more
        successful {IDMS}.
     
        Several versions of transaction processing were designed for
        GCOS-3 and GCOS-8.  An early attempt at TP for GCOS-3, not
        taken up in Europe, assumed that, as in {Unix}, a new process
        should be started to handle each transaction.  IBM customers
        required a more efficient model where multiplexed {threads}
        wait for messages and can share resources.  Those features
        were implemented as subsystems.
     
        GCOS-3 soon acquired a proper {TP monitor} called Transaction
        Driven System (TDS).  TDS was essentially a Honeywell
        development.  It later evolved into TP8 on GCOS-8.  TDS and
        its developments were commercially successful and predated IBM
        {CICS}, which had a very similar architecture.
     
        GCOS-6 and GCOS-4 (ex-GCOS-62) were superseded by {Motorola
        68000}-based {minicomputers} running {Unix} and the product
        lines were discontinued.
     
        In the late 1980s Bull took over Honeywell and Bull's
        management choose Unix, probably with the intent to move out
        of hardware into {middleware}.  Bull killed the Boston
        proposal to port Multics to a platform derived from DPS-6.
        Very few customers rushed to convert from GCOS to Unix and new
        machines (of CMOS technology) are still to be introduced in
        1997 with GCOS-8.  GCOS played a major role in keeping
        Honeywell a dismal also-ran in the {mainframe} market.
     
        Some early Unix systems at {Bell Labs} used GCOS machines for
        print spooling and various other services.  The field added to
        "/etc/passwd" to carry GCOS ID information was called the
        "{GECOS field}" and survives today as the "pw_gecos" member
        used for the user's full name and other human-ID information.
     
        [{Jargon File}]
     
        (1998-04-23)