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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 GeneralElectric 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
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
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 Motorola68000-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.