Жалпы Электрлік Жүйелік Операциялық Жүйесі (GCOS) тарихы

Operating system from General Electric

General Comprehensive Operating System (GCOS, '/dʒ//iː//k//oʊ//s/; originally GECOS, General Electric Comprehensive Operating Supervisor) is a family of operating systems oriented toward the 36 bit GE 600 series mainframe computers. The original version of GCOS was developed by General Electric beginning in 1962. The operating system is still used today in its most recent versions (GCOS 7 and GCOS 8) on servers and mainframes produced by Groupe Bull, primarily through emulation, to provide continuity with legacy mainframe environments. GCOS 7 and GCOS 8 are separate branches of the operating system and continue to be developed alongside each other.

The GECOS operating system was developed by General Electric for the 36 bit GE 600 series in 1962–1964; GE released GECOS I (with a prototype 635) in April 1965, GECOS II in November 1965 and GECOS III (with time sharing) in 1967. It bore a close resemblance architecturally to IBSYS on the IBM 7094 and less to DOS/360 on the IBM System/360. However, the GE 600 Series four processor architecture was very different from the System/360 and GECOS was more ambitious than DOS/360. GECOS III supported both time sharing (TSS) and batch processing, with dynamic allocation of memory (IBM had fixed partitions, at that time), making it a true second generation operating system.

After Honeywell acquired GE's computer division, GECOS III was renamed GCOS 3, and the hardware line was renamed to the Honeywell 6000 series, adding the EIS (enhanced instruction set, character oriented instead of word oriented).

The name "GCOS" was extended to the operating systems for all Honeywell marketed product lines. GCOS 64, a completely different 32 bit operating system for the Level 64 series, similar to a parallel development called Multics, was designed by Honeywell and Honeywell Bull developers in France and Boston. with changes made to support true virtual memory management and demand paging (these changes also required new hardware). GCOS 3 was supported in maintenance for several years after this announcement and renaming. Honeywell Bull published "Large Systems: GCOS 8 OS Time Sharing System User's Guide" in 1986.

DPS 6 and DPS 4 (ex Level 62) were superseded by Motorola 68000 and later on PowerPC minicomputers running Unix and the product lines were discontinued, though GCOS 6 ran in an emulator on top of AIX. The DPS 7 line, along with GCOS 7, continued to evolve into the DPS 7000 hardware base. In the late 1980s Honeywell sold its computer business to a joint venture that initially included NEC and Bull, with Honeywell still holding a stake for a time. Over a couple of years, Bull took over the company. NEC supplied several generations of mainframe hardware at the high end, which would run both GCOS 8 and their own ACOS 4 Operating System. Bull used the nomenclature DPS 9000 for its entire GCOS 8 based mainframe line, which included models designed by both Bull and NEC. By the late 1990s and early 2000s, Bull's desire was to center its development on a single hardware base, running commodity Intel chips but with Bull value adds. This platform, called Novascale and based on Itanium 2 processors, ran both Windows and Linux natively. However, instruction set simulators for both the DPS 7000 and DPS 9000 allowed GCOS 7 and GCOS 8 to run on this platform. The demise of the Itanium family required a change of hardware, and as of 2022, GCOS 7 and GCOS 8 are simulated on Bull Sequana M7200 and M9600 Xeon based hardware respectively. Support for GCOS 7 and GCOS 8 from Bull is planned through at least 2025 including regular hardware and software upgrades. A trace of GCOS influence remains today in modern UNIX systems. 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. Multics today, under the DPS8M simulator, retains the capability of running GCOS jobs, both batch and timesharing, via the "Multics GCOS Environment Simulator."

GCOS 3 (and later GCOS 7 and GCOS 8) featured a good Codasyl network database called Integrated Data Store (IDS) that was the model for the more successful IDMS. Multics, and WWMCCS, and has inherited a strong security structure in consequence. Hardware and software features combine to render the operating system unusually secure for an operating system of its generation and class. Multics influenced the design of the hardware, with gate oriented secure transfer of control instructions and a hardware enforced system of security levels very similar to that of the famous Multics rings. Operational environments such as WWMCCS drove development of special security features to allow secure hosting of classified information and compartmentalization. For a time separate versions of the GCOS system with special security features turned on were maintained specifically for government customers. Early versions of GCOS and the hardware it ran on did not support paged virtual memory but did support a single memory segment per process. This made it inferior for time sharing, especially compared with hardware designed to support Multics and the contemporaneous DEC PDP 10 hardware. GCOS is a process oriented OS, in which each process hosts one or more execution threads and executes in its own virtual memory space. and B.

Documentation were printed pages, available on premise to users (staff, students ), organized into steel binders, locked together in one monolithic steel reading rack, bolted to a table or counter, with pages organized for modular information updates, replacement, errata, and addenda.