GCOS /jee'kohs/ (General Comprehensive Operating System) is a family of Operating Systems orientated toward mainframes. Its initial member was developed by General Electric from 1962; originally called GECOS (the General Electric Comprehensive Operating Supervisor). In computing, an operating system (aka, OS) is the system software responsible for the direct control and management of hardware and basic system operations. ... Mainframes (often colloquially referred to as big iron) are large and expensive computers used mainly by government institutions and large companies for legacy applications, typically bulk data processing (such as censuses, industry/consumer statistics, ERP, and bank transaction processing). ... The General Electric Company, or GE (NYSE: GE) is a multinational technology and services company. ... 1962 (MCMLXII) was a common year starting on Monday (link will take you to calendar). ...

It is still in use nowadays, although this is very rare and often due to legacy reasons. Programs for this Operating System are usually written in COBOL, Fortran, or ALGOL. Look up legacy in Wiktionary, the free dictionary. ... COBOL is a third-generation programming language. ... Fortran (also FORTRAN) is a computer programming language originally developed in the 1950s; it is still used for scientific computing and numerical computation half a century later. ... ALGOL (short for ALGOrithmic Language) is a family of imperative computer programming languages originally developed in the mid 1950s which became the de facto standard way to report algorithms in print for almost the next 30 years. ...

System Architecture and Concepts

GCOS uses the concept of process to describe sequence of instructions executed in a processor on a set of data. It has also the concept of multi-threading. Additionally, there exist what is called a process group which is an entity containing several processes loaded and scheduled simultaneously. GCOS provides also semaphores which can be used to synchronise processes with each other or with the hardware. Many programming languages, operating systems, and other software development environments support what are called threads of execution. ... For schedule in computer science, see schedule (computer science). ...

Each process has its own address space, on which access rights can be a mix of READ, WRITE, and EXECUTE. The address space is segmented, allowing to share some part of the data between processes. Privilege management is done via rings. Each process is associated to one ring, the lower it is, the more privileges the process has.

The operating system is able to handle SMP based computers. It is based on a microkernel implemented in the firmware of the machine. It has also the ability to run in emulating modes with very little in speed loss. SMP is a three-letter abbreviation that can refer to the following: In computing: Symmetric multiprocessing, the use of multiple CPUs. ... It has been suggested that this article or section be merged with Kernel (computer science). ... In computing, firmware is software that is embedded in a hardware device. ...

History

The GECOS-II operating system was developed by General Electric for the 36-bit GE-635 in 1962-1964. Contrary to rumor, GECOS was not cloned from System/360 (unfortunately the on-line "Jargon File" has perpetuated a rumor that this was a "quick and dirty clone of System/360 DOS") - the GE-635 architecture was very different from the IBM 360 and GECOS was more ambitious than DOS/360. One of the hallmarks of the true second generation of this OS was its support of Time-sharing ("TSS") along with batch. The GE-600 series was a family mainframe computers of the 1960s, built by General Electric. ... 1962 (MCMLXII) was a common year starting on Monday (link will take you to calendar). ... For the Nintendo 64 emulator, see 1964 (Emulator). ... The IBM System/360 (S/360) is a mainframe computer system family announced by International Business Machines on April 7, 1964. ... The IBM System/360 (S/360) is a computer system family announced by International Business Machines on April 7, 1964. ... DOS/360 was the operating system announced by IBM at the low end for the System/360 in 1964 and delivered in 1965 or 1966. ... A hallmark is an official marking made by a trusted party, usually an assay office, on items made of precious metals (platinum, gold and silver) that guarantees a certain purity of the metal. ... Alternate uses: see Timesharing Time-sharing is an approach to interactive computing in which a single computer is used to provide apparently simultaneous interactive general-purpose computing to multiple users by sharing processor time. ... Batch processing is the sequential execution of a series of programs (jobs) on a computer. ...

After the buy-out of GE's computer division by Honeywell, GECOS-III was renamed GCOS-3, and the hardware line was renamed to the H-6000. Later Honeywell Marketing created a "Series" 60, and renamed the H-6000 to the Level-66. Honeywell, along with its European affliate CII-Honeywell Bull, also decided to launch a new product line called Level 64 (this later became the DPS-7). Honeywell NYSE: HON is a major American multinational corporation that produces electronic control systems and automation equipment. ... World map showing Europe Europe is conventionally considered one of the seven continents which, in this case, is more a cultural and political distinction than a physiogeographic one. ... Groupe Bull (also known as Bull Computer or, informally, as Bull) is a French computer company based in Paris. ...

The name "GCOS" was extended to all Honeywell-marketed product lines and GCOS-64, a completely different 32-bit operating system, significanctly inspired by a parallel development called "Multics," was designed by Honeywell and Honeywell Bull developers in France and Boston. GCOS-62, another different 32-bit low-end OS 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 from Massachusetts got the name GCOS-6. Multics (Multiplexed Information and Computing Service) was an extraordinarily influential early time-sharing operating system. ... Boston is a town and small port c. ... Minicomputer (colloquially, mini) is a largely obsolete term for a class of multi-user computers which make up the middle range of the computing spectrum, in between the largest multi-user systems (traditionally, mainframe computers) and the smallest single-user systems (microcomputers or personal computers). ... Official language(s) English Capital Boston Largest city Boston Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 44th 27,360 km² 305 km 80 km 25. ...

Yet another renaming of the product lines occurred in 1979, with the Level-6 becoming the DPS-6, the Level-61 becoming the DPS-4, the Level-64 becoming DPS-7, and Level-66 becoming DPS-8. Operating Systems retained the GCOS brand-name, with GCOS 6, GCOS 4, GCOS 7, and GCOS 8 being introduced. This caused some confusion in the customer base, since the original GCOS line, called GCOS-III (or GCOS-3), was now suddenly GCOS 8. GCOS-3 was supported in maintenance for several years after this announcement and renaming.

GCOS-3 (and later GCOS-7 and GCOS-8) featured a good Codasyl database called IDS (Integrated Data Store) that was the model for the more successful IDMS. CODASYL (often spelt Codasyl) is an acronym for COnference on DAta SYstems Languages. This was a IT industry consortium formed in 1959 to guide the development of a standard programming language that could be used on many computers. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Integrated Data Store (IDS) is a network database largely used by industry for its performance. ... IDMS (Integrated Database Management System) is a (network) CODASYL database management system first developed at B.F. Goodrich and later marketed by Cullinane Database Systems (renamed Cullinet in 1983). ...

Several transaction processing monitors were designed for GCOS-3 and GCOS-8. An early attempt at TP for GCOS-3 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. Wikibooks has more about this subject: Guide to UNIX Unix or UNIX is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T Bell Labs employees including Ken Thompson, Dennis Ritchie, and Douglas McIlroy. ... In computing, a process is a running instance of a program, including all variables and other state. ... A database transaction is a unit of interaction with a database management system or similar system that is treated in a coherent and reliable way independent of other transactions that must be either entirely completed or aborted. ...

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. A similar product also called TDS was developed for GCOS-7.

GCOS-6 and GCOS-4 (ex-GCOS-62) were superseded by Motorola 68000-based and 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. The Motorola 68000 is a CISC microprocessor, the first member of a successful family of microprocessors from Motorola, which were all mostly software compatible. ... PowerPC is a RISC microprocessor architecture created by the 1991 Apple-IBM-Motorola alliance, known as AIM. Originally intended for personal computers, PowerPC CPUs have since become popular embedded and high-performance processors as well. ... An emulator reproducing an arcade games playable atmosphere on a Windows computer. ... AIX or Aix may be: Aix, a genus of two species of dabbling ducks, the Wood Duck (Aix sponsa) and the Mandarin Duck (Aix galericulata) AIX operating system Athens Internet Exchange, (AIX) a European IXP a place name: Aix-la-Chapelle, or Aachen, a city in Germany in France: Aix...

In the late 1980s Honeywell sold its computer business to a joint venture that initially included NEC and Bull, with Honeywell for a time still holding a stake. 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. The 1980s decade refers to the years from 1980 to 1989, inclusive. ... The initials NEC may stand for: NEC Corporation, a multinational corporation formerly known as Nippon Electric Co. ...

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, runs 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. Bull continues to invest development money in support of both GCOS 7 and GCOS 8, and still has customers in several countries around the world. The 1990s decade refers to the years from 1990 to 1999, inclusive, the last decade of the 20th Century. ... Saddam Hussein shortly after his capture Major controversy over U. S. presidential election (November 7-December 13, 2000) September 11, 2001 terrorist attack on New Yorks World Trade Center and Virginias Pentagon killing almost 3000 people. ... Intel Corporation (NASDAQ: INTC, HKEx: 4335), founded in 1968 as Integrated Electronics Corporation, is a U.S.-based multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ... Itanium 2 brand logo The Itanium 2 is the successor of the first Itanium processor and is an IA-64 architecture microprocessor. ... Microsoft Windows is a series of operating environments and operating systems created by Microsoft for use on personal computers and servers. ... Tux is the official Linux mascot. ... An Instruction Set Simulator (ISS) is a simulation model, usually coded in a high-level language, which mimics the behavior of a processor by reading instructions and maintaining internal variables which represent the processors registers. ...

Trivia

One historical tidbit: 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. This article needs to be cleaned up to conform to a higher standard of quality. ...

See also

Operating systems timeline, Multics This article presents a timeline of events in the history of computer operating systems from 1960 to 2003. ... Multics (Multiplexed Information and Computing Service) was an extraordinarily influential early time-sharing operating system. ...

External links

• From GECOS to GCOS8 - An extensive history of GCOS.
• http://www.bull.com/servers/gcos8/ - The Groupe Bull GCOS8 product.