GE-600 series
Encyclopedia
The GE-600 series was a family of 36-bit
mainframe
computer
s originating in the 1960s, built by General Electric
(GE). When GE left the mainframe business the line was sold to Honeywell
, who built similar systems into the 1990s as the division moved to Groupe Bull
and then NEC.
s, eight 18-bit index register
s, and one 8-bit exponent register.
It supported floating point
in both 36-bit single-precision and 2 x 36-bit double precision, the exponent being stored separately, allowing up to 71 bits of precision (one bit being used for the sign). It had an elaborate set of addressing modes, many of which used indirect words, some of which were auto-incrementing or auto-decrementing. It supported 6-bit and 9-bit byte
s through addressing modes; these supported extracting specific bytes, and incrementing the byte pointer, but not random access to bytes.
It also included a number of channel controllers for handling I/O
. The CPU
could hand off short programs written in the channel controller's own machine language, which would then process the data, move it to or from the memory, and raise an interrupt
when they completed. This allowed the main CPU to move on to other tasks while waiting for the slow I/O to complete, a primary feature of time sharing systems.
, developed by GE beginning in 1962.
The GE-635 was used for the Dartmouth Time Sharing System
starting in 1965.
The GE Mark II operating system (later Mark III) was used by GE Information Services as the basis for its timesharing and networked computing business. Although Mark II / Mark III was originally based on the Dartmouth system, the systems quickly diverged. Mark II/III incorporated many features normally associated with on-line transaction-processing systems, such as journalization and granular file locking. In the early-to-mid-1970s, Mark III adopted a high-reliability cluster technology, in which up to eight processing systems (each with its own copy of the operating system) had access to multiple file systems.
The Multics
operating system was begun in 1964 as an advanced new operating system for the 600 series, though it was not production-ready until 1969. GE was hardware supplier to the project and one of development partners (the others were Massachusetts Institute of Technology
and Bell Labs
). GE saw this project as an opportunity to clearly separate themselves from other vendors by offering this advanced OS which would run best only on their machines. Multics required a number of additional features in the CPU to be truly effective, and John Couleur was joined by Edward Glaser at MIT to make the required modifications. The result was the GE-645, which included support for virtual memory
. Addressing was modified to use an 18-bit segment in addition to the 18-bit address, dramatically increasing the theoretical memory size and making virtual memory much easier to support.
project in 1959. MISTRAM was a tracking system that was used on a number of projects (including Project Apollo
) and the Air Force
required a data-collection computer to be installed in a tracking station downrange from Cape Canaveral
. The data would eventually be shared with the 36-bit IBM 7094 machine at the Cape, so the computer would likely have to be 36-bits as well (why they didn't use an IBM 7094 is something of a mystery). GE built a machine called the M236 for the task, and as a result of the 36-bit needs, it ended up acting a lot like the 7094. In fact GE offered a box to connect to the 635 called a 9SA that actually allowed the 635 to run 7094 programs.
GE originally hadn't intended on entering the commercial computer market with the machine. However by the early 1960s GE was the largest user of IBM mainframes, and producing their own machines seemed like an excellent way to lower the costs of their computing department. In one estimate the cost of development would be paid for in a single year of IBM rental fees. Many remained skeptical, but after a year of internal wrangling, the project to commercialize the M236 eventually got the go-ahead in February 1963.
The machine was originally offered as the main GE-635, and the slower but compatible GE-625 and GE-615. While most were single processor systems, the 635 could be configured with four CPUs and up to four input/output controllers (IOC's) each with up to 16 Common Peripheral Interface Channels.
The 635 was likely the first example of a general purpose SMP
system (although the GECOS/GCOS software treated the processors as a master, and up to three slaves). The 600 line consisted of six models: the 605, 615, 625, 635, 645, and 655.
The 615 was a 635 with Control Unit (CU) and Operations Unit (OU) overlap disabled, and a 36 bit wide memory path, and the 625 was a 635 with Control Unit and Operations Unit overlap disabled and 72 bit wide memory path; the 635 had a 72-bit wide memory path and CU/OU overlap enabled. The difference between these models was less than 10 wires on the backplane. Field service could convert a 615 to a 635 or 625 or vice versa in a couple of hours if necessary. Other than those few wires, the 615, 625 and 635 were identical. The 605 was used in some realtime/military applications, and was essentially a 615 without the floating point hardware. Programs coded for a 605 would run without any modification on any other 600 line processor
The 645 was a modified 635 processor that provided hardware support for the Multics
operating system developed at MIT. The 605/615/625/635 and 645 were essentially 2nd Generation Computers
(discrete transistor/TTL logic) with a handful of integrated circuits. Memory consisted of a two-microsecond ferrite core, (which could be interleaved). GE bought core memory from Fabri-Tek, Ampex and Lockheed. The Lockheed memory tended to be the most reliable.
The last model, the 655 was announced, but probably never delivered as a 655.
However continuing problems with the reliability of the magnetic tape
systems used with the system cast a pall over the entire project. In 1966 GE froze many orders while others were cancelled outright. By 1967 these problems were cleared up, and the machines were re-launched along with an upgraded version of the GECOS
operating system
.
A follow-on project to create a next-generation 635 started in 1967. The new GE-655 replaced the individual transistor
s from the earlier models with integrated circuit
s, which doubled the performance of the machine while also greatly reducing assembly costs. However the machine was still in development in 1969, by which time the Multics project had finally produced an operating system usable by end-users. Besides MIT, Bell Labs, and GE, GE-645 systems running Multics were installed at the US Air Force Rome Development Center, Honeywell
Billerica, and Machines Bull in Paris. These last two systems were used as a "software factory" by a Honeywell/Bull project to design the Honeywell Level 64 computer.
GE sold its computer division to Honeywell
in 1970, who renamed the GE-600 series as the Honeywell 6000 series. The 655 was officially released in 1973 as the Honeywell 6070 (with reduced performance versions, the 6030 and 6050). An optional Decimal/Business instruction set was added to improve COBOL performance. (Extended Instruction Set, aka EIS and the Decimal Unit or DU). The machines with EIS were the 'even' series, the 6040, 6060, 6080 and later the 6025. Several hundred of these processors were sold. Memory was initially 600 ns Ferrite core made by Lockheed. Later versions used 750 ns MOS memory. The two could co-exist within a system, but not within a memory controller.
A version of the 6080 with the various Multics-related changes similar to the 645 was released as the 6180. A few dozen 6180-architecture CPUs were shipped. Later members of the 6000 series were released under various names, including Level 66, Level 68, DPS-8, DPS-88, DPS-90, DPS-9000 by Honeywell, Groupe Bull
, and NEC.
36-bit word length
Many early computers aimed at the scientific market had a 36-bit word length. This word length was just long enough to represent positive and negative integers to an accuracy of ten decimal digits . It also allowed the storage of six alphanumeric characters encoded in a six-bit character encoding...
mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
s originating in the 1960s, built by General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
(GE). When GE left the mainframe business the line was sold to Honeywell
Honeywell
Honeywell International, Inc. is a major conglomerate company that produces a variety of consumer products, engineering services, and aerospace systems for a wide variety of customers, from private consumers to major corporations and governments....
, who built similar systems into the 1990s as the division moved to Groupe Bull
Groupe Bull
-External links:* * — Friends, co-workers and former employees of Bull and Honeywell* *...
and then NEC.
Architecture
The 600 series used 36-bit words and 18-bit addresses. They had two 36-bit accumulatorAccumulator (computing)
In a computer's central processing unit , an accumulator is a register in which intermediate arithmetic and logic results are stored. Without a register like an accumulator, it would be necessary to write the result of each calculation to main memory, perhaps only to be read right back again for...
s, eight 18-bit index register
Index register
An index registerCommonly known as a B-line in early British computers. in a computer's CPU is a processor register used for modifying operand addresses during the run of a program, typically for doing vector/array operations...
s, and one 8-bit exponent register.
It supported floating point
Floating point
In computing, floating point describes a method of representing real numbers in a way that can support a wide range of values. Numbers are, in general, represented approximately to a fixed number of significant digits and scaled using an exponent. The base for the scaling is normally 2, 10 or 16...
in both 36-bit single-precision and 2 x 36-bit double precision, the exponent being stored separately, allowing up to 71 bits of precision (one bit being used for the sign). It had an elaborate set of addressing modes, many of which used indirect words, some of which were auto-incrementing or auto-decrementing. It supported 6-bit and 9-bit byte
Byte
The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...
s through addressing modes; these supported extracting specific bytes, and incrementing the byte pointer, but not random access to bytes.
It also included a number of channel controllers for handling I/O
Input/output
In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...
. The CPU
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
could hand off short programs written in the channel controller's own machine language, which would then process the data, move it to or from the memory, and raise an interrupt
Interrupt
In computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution....
when they completed. This allowed the main CPU to move on to other tasks while waiting for the slow I/O to complete, a primary feature of time sharing systems.
Operating systems
Originally the operating system for the 600-series computers was GECOSGecos
GECOS or gecos may stand for:*General Electric Comprehensive Operating Supervisor , which was later renamed to General Comprehensive Operating System...
, developed by GE beginning in 1962.
The GE-635 was used for the Dartmouth Time Sharing System
Dartmouth Time Sharing System
The Dartmouth Time-Sharing System, or DTSS for short, was the first large-scale time-sharing system to be implemented successfully. DTSS was inspired by a PDP-1-based time-sharing system at Bolt, Beranek and Newman. In 1962, John Kemeny and Thomas Kurtz at Dartmouth College submitted a grant for...
starting in 1965.
The GE Mark II operating system (later Mark III) was used by GE Information Services as the basis for its timesharing and networked computing business. Although Mark II / Mark III was originally based on the Dartmouth system, the systems quickly diverged. Mark II/III incorporated many features normally associated with on-line transaction-processing systems, such as journalization and granular file locking. In the early-to-mid-1970s, Mark III adopted a high-reliability cluster technology, in which up to eight processing systems (each with its own copy of the operating system) had access to multiple file systems.
The Multics
Multics
Multics was an influential early time-sharing operating system. The project was started in 1964 in Cambridge, Massachusetts...
operating system was begun in 1964 as an advanced new operating system for the 600 series, though it was not production-ready until 1969. GE was hardware supplier to the project and one of development partners (the others were Massachusetts Institute of Technology
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
and Bell Labs
Bell Labs
Bell Laboratories is the research and development subsidiary of the French-owned Alcatel-Lucent and previously of the American Telephone & Telegraph Company , half-owned through its Western Electric manufacturing subsidiary.Bell Laboratories operates its...
). GE saw this project as an opportunity to clearly separate themselves from other vendors by offering this advanced OS which would run best only on their machines. Multics required a number of additional features in the CPU to be truly effective, and John Couleur was joined by Edward Glaser at MIT to make the required modifications. The result was the GE-645, which included support for virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
. Addressing was modified to use an 18-bit segment in addition to the 18-bit address, dramatically increasing the theoretical memory size and making virtual memory much easier to support.
History
It was developed by a team led by John Couleur out of work they had done for the military MISTRAMMISTRAM
MISTRAM was a high-resolution tracking system used by the United States Air Force to provide highly detailed trajectory analysis of rocket launches....
project in 1959. MISTRAM was a tracking system that was used on a number of projects (including Project Apollo
Project Apollo
The Apollo program was the spaceflight effort carried out by the United States' National Aeronautics and Space Administration , that landed the first humans on Earth's Moon. Conceived during the Presidency of Dwight D. Eisenhower, Apollo began in earnest after President John F...
) and the Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
required a data-collection computer to be installed in a tracking station downrange from Cape Canaveral
Cape Canaveral
Cape Canaveral, from the Spanish Cabo Cañaveral, is a headland in Brevard County, Florida, United States, near the center of the state's Atlantic coast. Known as Cape Kennedy from 1963 to 1973, it lies east of Merritt Island, separated from it by the Banana River.It is part of a region known as the...
. The data would eventually be shared with the 36-bit IBM 7094 machine at the Cape, so the computer would likely have to be 36-bits as well (why they didn't use an IBM 7094 is something of a mystery). GE built a machine called the M236 for the task, and as a result of the 36-bit needs, it ended up acting a lot like the 7094. In fact GE offered a box to connect to the 635 called a 9SA that actually allowed the 635 to run 7094 programs.
GE originally hadn't intended on entering the commercial computer market with the machine. However by the early 1960s GE was the largest user of IBM mainframes, and producing their own machines seemed like an excellent way to lower the costs of their computing department. In one estimate the cost of development would be paid for in a single year of IBM rental fees. Many remained skeptical, but after a year of internal wrangling, the project to commercialize the M236 eventually got the go-ahead in February 1963.
The machine was originally offered as the main GE-635, and the slower but compatible GE-625 and GE-615. While most were single processor systems, the 635 could be configured with four CPUs and up to four input/output controllers (IOC's) each with up to 16 Common Peripheral Interface Channels.
The 635 was likely the first example of a general purpose SMP
Symmetric multiprocessing
In computing, symmetric multiprocessing involves a multiprocessor computer hardware architecture where two or more identical processors are connected to a single shared main memory and are controlled by a single OS instance. Most common multiprocessor systems today use an SMP architecture...
system (although the GECOS/GCOS software treated the processors as a master, and up to three slaves). The 600 line consisted of six models: the 605, 615, 625, 635, 645, and 655.
The 615 was a 635 with Control Unit (CU) and Operations Unit (OU) overlap disabled, and a 36 bit wide memory path, and the 625 was a 635 with Control Unit and Operations Unit overlap disabled and 72 bit wide memory path; the 635 had a 72-bit wide memory path and CU/OU overlap enabled. The difference between these models was less than 10 wires on the backplane. Field service could convert a 615 to a 635 or 625 or vice versa in a couple of hours if necessary. Other than those few wires, the 615, 625 and 635 were identical. The 605 was used in some realtime/military applications, and was essentially a 615 without the floating point hardware. Programs coded for a 605 would run without any modification on any other 600 line processor
The 645 was a modified 635 processor that provided hardware support for the Multics
Multics
Multics was an influential early time-sharing operating system. The project was started in 1964 in Cambridge, Massachusetts...
operating system developed at MIT. The 605/615/625/635 and 645 were essentially 2nd Generation Computers
Transistor computer
A transistor computer is a computer which uses discrete transistors instead of vacuum tubes. The "first generation" of electronic computers used vacuum tubes, which generated large amounts of heat, were bulky, and were unreliable. A "second generation" of computers, through the late 1950s and...
(discrete transistor/TTL logic) with a handful of integrated circuits. Memory consisted of a two-microsecond ferrite core, (which could be interleaved). GE bought core memory from Fabri-Tek, Ampex and Lockheed. The Lockheed memory tended to be the most reliable.
The last model, the 655 was announced, but probably never delivered as a 655.
However continuing problems with the reliability of the magnetic tape
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...
systems used with the system cast a pall over the entire project. In 1966 GE froze many orders while others were cancelled outright. By 1967 these problems were cleared up, and the machines were re-launched along with an upgraded version of the GECOS
Gecos
GECOS or gecos may stand for:*General Electric Comprehensive Operating Supervisor , which was later renamed to General Comprehensive Operating System...
operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
.
A follow-on project to create a next-generation 635 started in 1967. The new GE-655 replaced the individual transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...
s from the earlier models with integrated circuit
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...
s, which doubled the performance of the machine while also greatly reducing assembly costs. However the machine was still in development in 1969, by which time the Multics project had finally produced an operating system usable by end-users. Besides MIT, Bell Labs, and GE, GE-645 systems running Multics were installed at the US Air Force Rome Development Center, Honeywell
Honeywell
Honeywell International, Inc. is a major conglomerate company that produces a variety of consumer products, engineering services, and aerospace systems for a wide variety of customers, from private consumers to major corporations and governments....
Billerica, and Machines Bull in Paris. These last two systems were used as a "software factory" by a Honeywell/Bull project to design the Honeywell Level 64 computer.
GE sold its computer division to Honeywell
Honeywell
Honeywell International, Inc. is a major conglomerate company that produces a variety of consumer products, engineering services, and aerospace systems for a wide variety of customers, from private consumers to major corporations and governments....
in 1970, who renamed the GE-600 series as the Honeywell 6000 series. The 655 was officially released in 1973 as the Honeywell 6070 (with reduced performance versions, the 6030 and 6050). An optional Decimal/Business instruction set was added to improve COBOL performance. (Extended Instruction Set, aka EIS and the Decimal Unit or DU). The machines with EIS were the 'even' series, the 6040, 6060, 6080 and later the 6025. Several hundred of these processors were sold. Memory was initially 600 ns Ferrite core made by Lockheed. Later versions used 750 ns MOS memory. The two could co-exist within a system, but not within a memory controller.
A version of the 6080 with the various Multics-related changes similar to the 645 was released as the 6180. A few dozen 6180-architecture CPUs were shipped. Later members of the 6000 series were released under various names, including Level 66, Level 68, DPS-8, DPS-88, DPS-90, DPS-9000 by Honeywell, Groupe Bull
Groupe Bull
-External links:* * — Friends, co-workers and former employees of Bull and Honeywell* *...
, and NEC.
External links
- The programming reference manual for the GE-635. Includes complete description of registers, instruction set, and addressing modes.
- Instruction set timings for the 625 and 635
- GE-645 Circuit Board
- Shangri-la and the Paris 645
- Myths about Multics