V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

GECOS
       General Electric Comprehensive Operating Supervisor / System (OS,
GE, GCOS, predecessor, Honeywell)


The Jargon File (version 4.4.7, 29 Dec 2003):

GECOS
 /jee'kohs/, n.

    See GCOS.


The Free On-line Dictionary of Computing (30 December 2018):

GCOS
GECOS
General Electric Comprehensive Operating System

    /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 chose 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) were 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)