Computer History Wiki - Recent changes [en]

EDVAC

Jnc — Tue, 15 Sep 2026 16:44:11 GMT

Fix grammar error; various clarifications

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	==History==		==History==

	The EDVAC was conceived the University of Pennsylvania's Moore School in 1945, while work was still proceeding on the ENIAC~~; early~~ consideration of how the ENIAC would be re-configured for a new problem indicated that that would be somewhat difficult. The notion of programmability was known already from the ASCC, and the [[Bell Telephone Laboratories relay computing devices\|Relay Interpolator]], and that promised to speed up switching the machine to a different problem. However, the electro-mechanical devices used on those machines to read the program were an order of magnitude slower than the electronic [[arithmetic logic unit\|calculation subsystem]], as were similar devices used to hold intermediate results. Use of an electronic [[memory]] to hold both the program ''and'' intermediate results was the obvious answer.		The EDVAC was conceived at the University of Pennsylvania's Moore School in 1945, while work was still proceeding on the ENIAC. Early consideration of how the ENIAC would be re-configured for a new problem indicated that that would be somewhat difficult. The notion of programmability was known already from the ASCC, and the [[Bell Telephone Laboratories relay computing devices\|Relay Interpolator]], and that promised to speed up switching the machine to a different problem. However, the electro-mechanical devices used on those machines to read the program were an order of magnitude slower than the electronic [[arithmetic logic unit\|calculation subsystem]], as were similar devices used to hold intermediate results. Use of an electronic [[memory]] to hold both the program ''and'' intermediate results was the obvious answer.

	[[John Mauchly]] and [[J. Presper Eckert]] had already begun to consider this change in direction, when [[Herman Goldstine]], the head of the project, introduced the mathematician [[John von Neumann]] (who was familiar with the idea of programs, from his knowledge of [[Alan Turing]]'s work on computability) to them. After further discussion, they rapidly came to rough agreement on the new approach, which almost every computer from that day forward has followed: a memory which merely stores things (unlike the accumulators of the ENIAC, which also contained limited computational capability), and a [[arithmetic logic unit\|~~separate subsystem~~]] which performs all the calculations. Von Neumann wrote up the results in his famous rough draft ''First Draft of a Report on the EDVAC'' - without noting who had contributed what, thereby igniting a controversy that was never really definitively settled.		[[John Mauchly]] and [[J. Presper Eckert]] had already begun to consider this change in direction, when [[Herman Goldstine]], the head of the project, introduced the mathematician [[John von Neumann]] (who was familiar with the idea of programs, from his knowledge of [[Alan Turing]]'s work on computability) to them. After further discussion, they rapidly came to rough agreement on the new approach, which almost every computer from that day forward has followed: a memory which merely stores things (unlike the accumulators of the ENIAC, which also contained limited computational capability), and a separate subsystem the [[arithmetic logic unit\|ALU]], which performs all the calculations. Von Neumann wrote up the results in his famous rough draft ''First Draft of a Report on the EDVAC'' - without noting who had contributed what, thereby igniting a controversy that was never really definitively settled.

	The First Draft, dated June 30, 1945, was circulated fairy widely in that form by Goldstine, and was the inspiration for most of the first generation of computers; almost all computers now are descendants. The EDVAC itself was not very influential: Mauchly and Eckert left the Moore School shortly ~~thereafter~~, over a dispute about patents; von Neumann moved to the [[Institute for Advanced Study]] to build his [[IAS computer]]. Their loss slowed down the project so much that the machine was not finally operational until 1952.		The First Draft, dated June 30, 1945, was circulated fairy widely in that form by Goldstine, and was the inspiration for most of the first generation of computers; almost all computers now are descendants. The EDVAC itself was not very influential: Mauchly and Eckert left the Moore School shortly after the First Draft came out, over a dispute with the Moore School about patents; von Neumann moved to the [[Institute for Advanced Study]] to build his [[IAS computer]]. Their loss slowed down the project so much that the machine was not finally operational until 1952.

	==Details==		==Details==

Maurice Wilkes

Jnc — Tue, 15 Sep 2026 16:32:28 GMT

Add his two books

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	'''Maurice V. Wilkes''' was a British computer scientist, in 1951 ~~was~~ Director of the Mathematical Laboratory of the University of Cambridge. Among his accomplishments were [[EDSAC]] (the first usable stored-[[program]] [[computer]]) and popularizing the use of [[microcode]].		'''Maurice V. Wilkes''' was a British computer scientist; in 1951, Director of the Mathematical Laboratory of the University of Cambridge. Among his accomplishments were leading the creation of [[EDSAC]] (the first usable stored-[[program]] [[computer]]), and popularizing the use of [[microcode]].

	He has written many articles and books, among them:		He has written many articles and books, among them:
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	{{semi-stub}}		{{semi-stub}}

			==Further reading==

			* Maurice V. Wilkes, ''Memoirs of a Computer Pioneer'', MIT Press, Cambridge, 1985 - autobiography
			* Maurice V. Wilkes, ''Computing Perspectives'', Morgan Kaufmann, San Francisco, 1995 - essays on various topics

	==External links==		==External links==

Multics

Jnc — Tue, 15 Sep 2026 08:27:36 GMT

Fix minor unintentional error caused by loose wording

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	\| architecture = [[GE-645]] initially, various [[Honeywell 6000 series\|Honeywell 6000]] models later		\| architecture = [[GE-645]] initially, various [[Honeywell 6000 series\|Honeywell 6000]] models later
	}}		}}
			'''Multics''' (''Multi''plexed ''I''nformation and ''C''omputing ''S''ervice - although the short form is ''never'' spelled in all capitals) was an early [[time-sharing]] [[operating system]] which has influenced almost every operating system created since; especially via [[UNIX]] (the name of which is a play on 'Multics'), which was created by [[Bell Laboratories\|Bell Labs]] personnel who had worked on Multics, after Bell Labs pulled out of the Multics project.
	Multics (''Multi''plexed ''I''nformation and ''C''omputing ''S''ervice - although the short form is ''never'' spelled in all capitals) was an early [[time-sharing]] [[operating system]] which has influenced almost every operating system created since; especially via [[UNIX]] (the name of which is a play on 'Multics'), which was created by [[Bell Laboratories\|Bell Labs]] personnel who had worked on Multics, after Bell Labs pulled out of the Multics project.

	Multics was intended as an ''information utility''; i.e. a service to which those who wanted information processing would connect, much as people connect to the electric grid for power.		Multics was intended as an ''information utility''; i.e. a service to which those who wanted information processing would connect, much as people connect to the electric grid for power.
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	Multics ran only on special hardware, which provided hardware support for its single-level store [[architecture]].		Multics ran only on special hardware, which provided hardware support for its single-level store [[architecture]].

	It initially ran on the [[GE 645]], a modified version of the [[GE 635]]. After GE was bought by Honeywell, a number of models of the [[Honeywell 6000 series]] systems were produced to run Multics on.		It initially ran on the [[GE 645]], a modified version of the [[GE 635]]. After [[General Electric\|GE]]'s computer business was bought by [[Honeywell]], a number of models of the [[Honeywell 6000 series]] systems were produced to run Multics on.

	== Multics today ==		== Multics today ==

	Multics is dead. There are no systems running it today (the last one was ~~[http://slashdot.org/articles/00/11/13/066228.shtml~~ shut down in 2000]).		Multics is dead. There are no systems running it today (the last one was shut down in 2000).

	There is however now a working [[SIMH]]-based emulator for the Multics DPS-8/M hardware, and with most of the source code still extant, it is now possible to experience the Multics computing environment.		There is however now a working [[SIMH]]-based emulator for the Multics DPS-8/M hardware, and with most of the source code still extant, it is now possible to experience the Multics computing environment.
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	* [https://softpanorama.org/History/multics.shtml Multix OS -- Pioneer of time sharing]		* [https://softpanorama.org/History/multics.shtml Multix OS -- Pioneer of time sharing]
	* [https://www.youtube.com/watch?v=jni7wk7bjxA Multics booting] - A video of a H6180 CPU front panel hooked up to a SIMH H6180 emulation booting Multics		* [https://www.youtube.com/watch?v=jni7wk7bjxA Multics booting] - A video of a H6180 CPU front panel hooked up to a SIMH H6180 emulation booting Multics
			* [http://slashdot.org/articles/00/11/13/066228.shtml The Last Multics System Decommissioned]
			** [https://tech.slashdot.org/story/17/07/09/0414245/48-year-old-multics-operating-system-resurrected 48-Year-Old Multics Operating System Resurrected]

	[[Category: Operating Systems]]		[[Category: Operating Systems]]

Notable early computing devices

Jnc — Tue, 15 Sep 2026 07:58:40 GMT

ABC most notable for being the first electronic digital computing device; add a link

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	==Electronic computing devices==		==Electronic computing devices==

	At about the same time as the ASCC, in 1938, [[John Vincent Atanasoff]] took the next step, and began the creation of the first [[electronic]] digital computing device, later called the [[Atanasoff-Berry Computer]]. It was not at all programmable or general-purpose; it could only solve systems of simultaneous equations. It was notable for having probably inspired [[John Mauchly]] to use a digital electronic approach when he later set out to build the [[ENIAC]]; and ~~also~~ for being the first digital electronic computing device to use [[capacitor]]-based memory - an approach to memory now ubiquitous in the [[Dynamic RAM]] of all modern computers.		At about the same time as the ASCC, in 1938, [[John Vincent Atanasoff]] took the next step, and began the creation of the first [[electronic]] digital computing device, later called the [[Atanasoff-Berry Computer]]. It was not at all programmable or general-purpose; it could only solve systems of simultaneous equations. It was also notable for having probably inspired [[John Mauchly]] to use a digital electronic approach when he later set out to build the [[ENIAC]]; and for being the first digital electronic computing device to use [[capacitor]]-based memory - an approach to memory now ubiquitous in the [[Dynamic RAM]] of all modern computers.

	The [[Colossus]] digital electronic code-breaking devices of [[Tommy Flowers]], built in the UK during World War Two (construction of the first one started in 1943), were notable because they showed that large electronic computing devices could be made to operate reliably; because quite a few were produced; and because many of the post-War computer pioneers in the UK learned about the suitability of electronics for digital computing devices from them. They are often described as 'programmable', but this is incorrect - they had no program of any form, and they were not general-purpose; a better description is 'configurable'.		The [[Colossus]] digital electronic code-breaking devices of [[Tommy Flowers]], built in the UK during World War Two (construction of the first one started in 1943), were notable because they showed widely that large electronic computing devices could be made to operate reliably; because quite a few were produced; and because many of the post-War computer pioneers in the UK learned about the suitability of electronics for digital computing devices from them. They are often described as 'programmable', but this is incorrect - they had no program of any form, and they were not general-purpose; a better description is 'configurable'.

	Effectively the last step before true computers was the ENIAC, a large digital electronic computing device. As originally designed, it was only configurable, requiring considerable effort to re-configure it to perform a different computation (although it was general-purpose, unlike the Atanasoff–Berry Computer and Colossus). In 1947 an effort was started to re-configure it in a way that added a certain amount of programmability, via a program stored in the 'function-table switches' (originally intended as a ROM data source). Later, minor [[hardware]] modifications improved ENIACs efficiency when configured as a stored-program machine; it started to operate in that mode in 1948.		Effectively the last step before true computers was the ENIAC, a large digital electronic computing device. As originally designed, it was only configurable, requiring considerable effort to re-configure it to perform a different computation (although it was general-purpose, unlike the Atanasoff–Berry Computer and Colossus). In 1947 an effort was started to re-configure it in a way that added a certain amount of programmability, via a program stored in the 'function-table switches' (originally intended as a [[read-only memory\|ROM]] data source). Later, minor [[hardware]] modifications improved ENIACs efficiency when configured as a stored-program machine; it started to operate in that mode in 1948.

	==Further reading==		==Further reading==

Program

Jnc — Tue, 15 Sep 2026 07:33:59 GMT

Fix garble; minor language improvements

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	* [[expression]]s to perform arithmetical and/or logical computations		* [[expression]]s to perform arithmetical and/or logical computations
	* directives to move data from one place to another		* directives to move data from one place to another
	* [[control flow]] mandates, including [[conditional branch]]es and [[subroutine]] calls		* [[control flow]] mandates, including [[jump]]s, [[conditional branch]]es, and [[subroutine]] calls

	A program almost always exists in two complementary forms:		A program almost always exists in two complementary forms:

	* as [[object code]] (often referred to as 'binary'), a collection of [[instruction]]s loaded into the [[main memory]] of the [[computer]], from where the [[Central Processing Unit\|CPU]] will [[fetch]] the individual instructions of the program, and [[execute]] them;		* as [[object code]] (often referred to as 'binary'); a collection of [[instruction]]s loaded into the [[main memory]] of the [[computer]], from where the [[Central Processing Unit\|CPU]] will [[fetch]] the individual instructions of the program, and [[execute]] them;
	* the [[source code]]; the expression, in either [[assembly language]] or a higher-level [[programming language]] (forms more suited for ~~humans to~~ humans to work with), of the steps in the program.		* the [[source code]]; the expression, in either [[assembly language]] or a higher-level [[programming language]] (forms more suited for humans to work with), of the steps in the program.

	Programs, almost all originally created in the latter form, are converted from their original human-readable source code, to the object code form needed by an actual computer, by tools such as [[assembly language\|assembler]]s and [[compiler]]s.		Programs, almost all originally created in the latter form, are converted from their original human-readable source code, to the object code form needed by an actual computer, by tools such as [[assembly language\|assembler]]s and [[compiler]]s.
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	==Early programs==		==Early programs==

	In the context of early [[computing device]]s, it must be emphasized that a program was a specified series of elementary steps, which were stored in some mechanism from which they were fed into the device; not simply the ability to make ~~physical~~ changes to the device, to change what calculation it ~~performs~~ - even if those changes were instantiated in something that was added to the device for the accomplishment of that exact purpose, like the [[plug-board]]s of the [[ENIAC]]. Such 'customizability' is better referred to as 'configurability', and ''not'' 'programmability'.		In the context of early [[computing device]]s, it must be emphasized that a program was a specified series of elementary steps, which were stored in some mechanism from which they were fed into the device. They were ''not'' simply the ability to make changes to the device, to change what calculation it performed - even if those changes were instantiated in something that was added to the device for the accomplishment of that exact purpose (like the [[plug-board]]s of the [[ENIAC]]). Such 'customizability' is better referred to as 'configurability', and ''not'' 'programmability'.

	==Further reading==		==Further reading==
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	* Nicholas Metropolis, J. Worlton, [https://www.osti.gov/servlets/purl/4628499 ''A Trilogy On Errors in the History of Computing''], Los Alamos National Laboratory, Los Alamos, 1972 - contains an in-depth section on the genesis of the 'stored program' idea, by someone who lived through the end of that era, and knew those who did the work		* Nicholas Metropolis, J. Worlton, [https://www.osti.gov/servlets/purl/4628499 ''A Trilogy On Errors in the History of Computing''], Los Alamos National Laboratory, Los Alamos, 1972 - contains an in-depth section on the genesis of the 'stored program' idea, by someone who lived through the end of that era, and knew those who did the work
	<!-- https://www.osti.gov/biblio/4628499 -->		<!-- https://www.osti.gov/biblio/4628499 -->

	~~{{semi-stub}}~~

	[[Category: Basics]]		[[Category: Basics]]

PDP-10

Larsbrinkhoff — Mon, 14 Sep 2026 10:13:48 GMT

Hobbyist recreations: Gary Solomon's "KI10"

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	* David Bridgham: [http://pdp10.froghouse.org/ KV10 (in progress)]		* David Bridgham: [http://pdp10.froghouse.org/ KV10 (in progress)]
	* Angelo Papenhoff: [https://github.com/aap/fpdpga FPDPGA], PDP-6 and KA10 FPGA.		* Angelo Papenhoff: [https://github.com/aap/fpdpga FPDPGA], PDP-6 and KA10 FPGA.
			* Gary Solomon: [https://garysolomon199.substack.com/ A KI10-like computer]

	==Software simulators==		==Software simulators==

General Comprehensive Operating System

Jnc — Sun, 13 Sep 2026 21:26:11 GMT

Better than a stub - but not by much

New page

The '''General Comprehensive Operating System''' (usually given as the acronym, '''GCOS''') was the most common [[operating system]] for [[Honeywell 6000 series]] [[mainframe]]s and descendants, from [[Honeywell]], and then [[Groupe Bull]] - themselves descendants of earlier machines ([[GE 600 series]]) from [[General Electric]] (GE). It was still in use recently (in its most recent versions - GCOS 7 and GCOS 8) on follow-on machines from Groupe Bull.

GCOS itself was an evolution of the earlier GECOS (General Electric Comprehensive Operating Supervisor) from GE, from before Honeywell bought GE's mainframe computer business, when GE decided to leave that market (although early Honeywell documentation continued to call it GECOS). Groupe Bull, in turn, inherited GCOS when Honeywell in turn decided to exit the large-scale computer business.

GCOS did mot initially support [[virtual memory]]; the machines on which it then ran only had [[base and bounds]] [[memory management]] [[hardware]].

It was originally developed by GE for the GE 600 series in 1962–1964; GE released GECOS I in April, 1965, on the [[GE-635]].

{{semi-stub}}

==External links==

* [https://bitsavers.org/pdf/ge/GE-6xx/GECOS/ GECOS] - for the GE-6xx
** [https://bitsavers.org/pdf/ge/GE-6xx/GECOS/CPB-1002_GECOS_Jul64.pdf GE-635 Comprehensive Operating Supervisor] (July 1964)
* [https://bitsavers.org/pdf/ge/GE-6xx/GECOS-III/ GECOS-III]
* [https://bitsavers.org/pdf/honeywell/large_systems/ Large Systems] - numerous GECOS sub-folders
* [https://multics-wiki.swenson.org/gcos GCOS] - at the Multics Wiki; contains much information about GCOS
* [http://www.feb-patrimoine.com/english/gecos_to_gcos8_part_2.htm From GECOS to GCOS8: Part II - The Honeywell years]

[[Category: Operating Systems]]

Honeywell 6000 series

Jnc — Sun, 13 Sep 2026 18:53:57 GMT

Have a target, now

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	They were descendants of the [[GE 600 series]] family; after GE's computer business was sold to [[Honeywell]] in 1970, the 6000 series were Honeywell's replacements. They used [[Transistor-transistor logic\|TTL]] [[Integrated circuit\|SSI integrated circuits]] and larger [[printed circuit board]]s, unlike the older (and obsolescent) discrete [[transistor]] GE machines.		They were descendants of the [[GE 600 series]] family; after GE's computer business was sold to [[Honeywell]] in 1970, the 6000 series were Honeywell's replacements. They used [[Transistor-transistor logic\|TTL]] [[Integrated circuit\|SSI integrated circuits]] and larger [[printed circuit board]]s, unlike the older (and obsolescent) discrete [[transistor]] GE machines.

	The basic [[architecture]] of the GE and Honeywell series was the same: a [[tightly-coupled]] [[multi-processor]], with all the [[Central Processing Unit\|CPUs]] sharing access to a collection of [[multi-port memory]] units. All models used 36-bit [[word]]s, and almost identical [[instruction set]]s; Honeywell added an [[~~Commercial Instruction Set\|~~Extended Instruction Set]] (EIS) which provided string-manipulation instructions, [[binary-coded decimal\|packed decimal]] instructions, etc.		The basic [[architecture]] of the GE and Honeywell series was the same: a [[tightly-coupled]] [[multi-processor]], with all the [[Central Processing Unit\|CPUs]] sharing access to a collection of [[multi-port memory]] units. All models used 36-bit [[word]]s, and almost identical [[instruction set]]s; Honeywell added an [[Extended Instruction Set]] (EIS) which provided string-manipulation instructions, [[binary-coded decimal\|packed decimal]] instructions, etc.

	Most 6000 series machines ran [[GCOS]] (General Comprehensive Operating System), an evolution of the earlier GECOS (General Electric Comprehensive Operating Supervisor) - early Honeywell documentation continued to call it GECOS.		Most 6000 series machines ran [[GCOS]] (General Comprehensive Operating System), an evolution of the earlier GECOS (General Electric Comprehensive Operating Supervisor) - early Honeywell documentation continued to call it GECOS.

Extended Instruction Set

Jnc — Sun, 13 Sep 2026 18:52:44 GMT

Can have two meanings

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	'''Extended Instruction Set''' was the name given to a number of optional additions, to different models from different manufacturers, to their [[Central Processing Unit\|CPUs]]; those added [[instruction]]s to the basic set provided by the CPU of the 'base' model of any line.		'''Extended Instruction Set''' was the name given to a number of optional additions, to different models from different manufacturers, to their [[Central Processing Unit\|CPUs]]; those added [[instruction]]s to the basic set provided by the CPU of the 'base' model of any line. The term could apply to either the formal specification of the added instructions, or the piece of physical [[hardware]] which implemented them.

	(This concept obviously only made sense when CPUs were physically large constructs, made up of many discrete components, such as [[transistor]]s or SSI [[integrated circuit\|chips]]. Only the very earliest [[microprocessor]]s had such options, often [[floating point]] arithmetic units.)		(This concept obviously only made sense when CPUs were physically large constructs, made up of many discrete components, such as [[transistor]]s or SSI [[integrated circuit\|chips]]. Now that CPUs are extremely complex monolithic constructs, the concept no longer makes any sense. Only the very earliest [[microprocessor]]s had such options, often [[floating point]] arithmetic units.)

	{{semi-stub}}		{{semi-stub}}

EIS

Jnc — Sun, 13 Sep 2026 18:45:11 GMT

Better target

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	#Redirect [[~~PDP-11~~ Extended Instruction Set]]		#Redirect [[Extended Instruction Set]]

Extended Instruction Set

Jnc — Sun, 13 Sep 2026 18:44:30 GMT

Turn into a semi-stub

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	~~#Redirect~~ [[Commercial Instruction Set]]		'''Extended Instruction Set''' was the name given to a number of optional additions, to different models from different manufacturers, to their [[Central Processing Unit\|CPUs]]; those added [[instruction]]s to the basic set provided by the CPU of the 'base' model of any line.

			(This concept obviously only made sense when CPUs were physically large constructs, made up of many discrete components, such as [[transistor]]s or SSI [[integrated circuit\|chips]]. Only the very earliest [[microprocessor]]s had such options, often [[floating point]] arithmetic units.)

			{{semi-stub}}

			==See also==

			* [[PDP-11 Extended Instruction Set]]
			* [[Commercial Instruction Set]]
			* [[PDP-11 Commercial Instruction Set]]
			* [[Honeywell 6000 series]]

			[[Category: CPU Basics]]

Honeywell 6000 series

Jnc — Sun, 13 Sep 2026 18:23:30 GMT

Clarify

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	They were descendants of the [[GE 600 series]] family; after GE's computer business was sold to [[Honeywell]] in 1970, the 6000 series were Honeywell's replacements. They used [[Transistor-transistor logic\|TTL]] [[Integrated circuit\|SSI integrated circuits]] and larger [[printed circuit board]]s, unlike the older (and obsolescent) discrete [[transistor]] GE machines.		They were descendants of the [[GE 600 series]] family; after GE's computer business was sold to [[Honeywell]] in 1970, the 6000 series were Honeywell's replacements. They used [[Transistor-transistor logic\|TTL]] [[Integrated circuit\|SSI integrated circuits]] and larger [[printed circuit board]]s, unlike the older (and obsolescent) discrete [[transistor]] GE machines.

	The basic [[architecture]] of the GE and Honeywell series was the same: a [[tightly-coupled]] [[multi-processor]], with all the [[Central Processing Unit\|CPUs]] sharing access to a collection of [[multi-port memory]] units. All used 36-bit [[word]]s, and almost identical [[instruction set]]s; Honeywell added an [[Commercial Instruction Set\|Extended Instruction Set]] (EIS) which provided string-manipulation instructions, [[binary-coded decimal\|packed decimal]] instructions, etc.		The basic [[architecture]] of the GE and Honeywell series was the same: a [[tightly-coupled]] [[multi-processor]], with all the [[Central Processing Unit\|CPUs]] sharing access to a collection of [[multi-port memory]] units. All models used 36-bit [[word]]s, and almost identical [[instruction set]]s; Honeywell added an [[Commercial Instruction Set\|Extended Instruction Set]] (EIS) which provided string-manipulation instructions, [[binary-coded decimal\|packed decimal]] instructions, etc.

	Most 6000 series machines ran [[GCOS]] (General Comprehensive Operating System), an evolution of the earlier GECOS (General Electric Comprehensive Operating Supervisor) - early Honeywell documentation continued to call it GECOS.		Most 6000 series machines ran [[GCOS]] (General Comprehensive Operating System), an evolution of the earlier GECOS (General Electric Comprehensive Operating Supervisor) - early Honeywell documentation continued to call it GECOS.

GE-635

Jnc — Sat, 12 Sep 2026 15:07:41 GMT

Tweak DTSS mention

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	The '''GE-635''' was a [[transistor]] [[mainframe]] computer; the largest of the [[GE 600 series‎]] family. It is notable mostly for being the design base of the [[GE-645]], a descendant created for the [[Multics]] project (after [[International Business Machines\|IBM]] refused to add necessary features such as [[virtual memory]] to the [[IBM System/360\|System 360]]). The [[Dartmouth Time Sharing System]], where [[BASIC]] was developed, also ran on the GE-635.		The '''GE-635''' was a [[transistor]] [[mainframe]] computer; the largest of the [[GE 600 series‎]] family. It is notable mostly for being the design base of the [[GE-645]], a descendant created for the [[Multics]] project (after [[International Business Machines\|IBM]] refused to add necessary features such as [[virtual memory]] to the [[IBM System/360\|System 360]]). The [[Dartmouth Time Sharing System]], where [[BASIC]] was developed, also eventually ran on the GE-635.

	The basic overall [[architecture]] of the GE-635 was inherited by the later Multics systems: it was a [[tightly-coupled]] [[multi-processor]], with all the [[Central Processing Unit\|CPUs]] sharing access to a collection of [[multi-port memory]] modules. [[Input/output\|I/O]] activities were handled by Input/Output Controller modules, similarly sharing access to the memory modules.		The basic overall [[architecture]] of the GE-635 was inherited by the later Multics systems: it was a [[tightly-coupled]] [[multi-processor]], with all the [[Central Processing Unit\|CPUs]] sharing access to a collection of [[multi-port memory]] modules. [[Input/output\|I/O]] activities were handled by Input/Output Controller modules, similarly sharing access to the memory modules.

	The GE-635 was intended for [[multi-tasking\|multi-programming]]; a CPU operated in either Master mode, in which there were no limitations on its operation, or Slave mode, in which [[base and bounds]] type [[memory management]] applied.		The GE-635 was intended for [[multi-tasking\|multi-programming]]; a CPU operated in either 'Master' mode, in which there were no limitations on its operation, or 'Slave' mode, in which [[base and bounds]] type [[memory management]] applied.

	The GE-635 was a 36-bit machine, as was common for scientific computers in that period. The CPU included a single double-width [[register\|accumulator]], and eight [[index register]]s (18 bits wide; the size of [[address]]es in the GE-635). The [[Program Counter]] was also 18 bits.		The GE-635 was a 36-bit machine, as was common for scientific computers in that period. The CPU included a single double-width [[register\|accumulator]], and eight [[index register]]s (18 bits wide; the size of [[address]]es in the GE-635). The [[Program Counter]] was also 18 bits.

GCOS

Jnc — Sat, 12 Sep 2026 09:35:30 GMT

Redir - short form

New page

#Redirect [[General Comprehensive Operating System]]

Michigan Algorithm Decoder

Jnc — Fri, 11 Sep 2026 14:55:18 GMT

Add minimal details on the evolution

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	'''Michigan Algorithm Decoder''' (usually given as its acronym, '''MAD''') was a [[compiler\|compiled]] [[programing language]]~~, originally for the~~ [[~~IBM 7090~~]]~~. It~~ was in spirit (but not [[syntax]]) ~~similar to [[ALGOL]]~~.		'''Michigan Algorithm Decoder''' (usually given as its acronym, '''MAD''') was a [[compiler\|compiled]] [[programing language]]. It was based on [[ALGOL]] 58, to which it was similar in spirit (but not [[syntax]]).

	It was ~~later~~ moved to the [[IBM 7094]], and ~~was much used on~~ [[~~Compatible Time-Sharing System\|CTSS~~]].		The compiler was originally written in 1959 for the [[IBM 704]]; it was subsequentially moved to the [[IBM 709]], [[IBM 7090]] and [[IBM 7094]] by the University of Michigan Computing Center staff. Other groups elsewhere moved it to the [[IBM 7040]], [[Philco]] 210-211, and [[Sperry Rand]] 1107.

	{{stub}}		It was much used on [[Compatible Time-Sharing System\|CTSS]].

			{{semi-stub}}

	==External links==		==External links==

	* [http://www.bitsavers.org/pdf/univOfMichigan/mad/L2-UOI-MAD1-2-RX_MADum_62.pdf A User's Reference Manual for The Michigan Algorithm Decoder (MAD) for the IBM 7090]		* [http://www.bitsavers.org/pdf/univOfMichigan/mad/L2-UOI-MAD1-2-RX_MADum_62.pdf A User's Reference Manual for The Michigan Algorithm Decoder (MAD) for the IBM 7090] - 1962 version
			* [https://people.csail.mit.edu/saltzer/Multics/CTSS-Documents/MAD-manual.pdf The Michigan Algorithm Decoder (The MAD Manual)] - 1966 version

	[[Category: Languages]]		[[Category: Languages]]

IBM 7094

Jnc — Fri, 11 Sep 2026 14:27:59 GMT

Final CTSS host

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	\| price = roughly US$3.5M		\| price = roughly US$3.5M
	}}		}}

	The '''IBM 7094''' was IBM's last commercial scientific [[mainframe]] (built at a time when computers for scientific and business computing used separate [[instruction set]]s).		The '''IBM 7094''' was IBM's last commercial scientific [[mainframe]] (built at a time when computers for scientific and business computing used separate [[instruction set]]s).

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	Total production amounted to 130 7094 I's, and 125 7094 II's.		Total production amounted to 130 7094 I's, and 125 7094 II's.

			The 7094 was the final IBM model upon which [[Compatible Time-Sharing System\|CTSS]] ran.

			{{semi-stub}}

	==Further reading==		==Further reading==
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	* [http://www.quadibloc.com/comp/cp0309.htm From the IBM 704 to the IBM 7094]		* [http://www.quadibloc.com/comp/cp0309.htm From the IBM 704 to the IBM 7094]
	* [http://www.frobenius.com/7090.htm IBM 7090/94 Architecture]		* [http://www.frobenius.com/7090.htm IBM 7090/94 Architecture]
			* [https://people.csail.mit.edu/saltzer/Multics/CTSS-Documents/RPQs/RPQs.html IBM 7094 Hardware Modifications for CTSS (RPQs)]
	~~{{semi~~-~~stub}}~~

	[[Category: IBM Mainframes]]		[[Category: IBM Mainframes]]

SimH Classic

Larsbrinkhoff — Thu, 10 Sep 2026 07:03:30 GMT

Newest relsease is V3.12-5. There is no GitHub repository for Classic.

← Older revision		Revision as of 07:03, 10 September 2026
(One intermediate revision by the same user not shown)
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	SIMH was primarily written by Bob Supnik of [[Zork]] porting fame, and is now widely contributed to by others as well.		SIMH was primarily written by Bob Supnik of [[Zork]] porting fame, and is now widely contributed to by others as well.

	The current version is V3.12-2, released on ~~April 25th~~, ~~2022. More up to date developments may be found on their GitHub [[source code]] repository~~.		The current version is V3.12-5, released on July 16th, 2024.

	== Emulated Systems ==		== Emulated Systems ==
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	=== DEC PDP-10 ===		=== DEC PDP-10 ===

	The [[PDP-10]] model [[KS10]] processor is emulated and will run all but the latest versions of the [[TOPS-10]] and [[TOPS-20]] operating systems.		The [[PDP-10]] model [[KS10]] processor is emulated and will run ITS and all but the latest versions of the [[TOPS-10]] and [[TOPS-20]] operating systems.

	Richard Cornwell contributed a new emulator that supports [[KA10]], [[KI10]], [[KL10]] model A and B, and [[KS10]]. It can run most versions of TOPS-10 and TOPS-20, as well as [[Incompatible Timesharing System\|ITS]], [[WAITS]], and (soon) [[TENEX]].		Richard Cornwell contributed a new emulator that supports [[KA10]], [[KI10]], [[KL10]] model A and B, and [[KS10]]. It can run most versions of TOPS-10 and TOPS-20, as well as [[Incompatible Timesharing System\|ITS]], [[WAITS]], and (soon) [[TENEX]].

SIMH/Draft

Jnc — Wed, 09 Sep 2026 01:45:00 GMT

Jnc deleted page SIMH/Draft Useless: No use now that the Draft page is gone

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	The '''GE-635''' was a [[transistor]] [[mainframe]] computer; the largest of the [[GE 600 series‎]] family. It is notable mostly for being the design base of the [[GE-645]], a descendant created for the [[Multics]] project (after [[International Business Machines\|IBM]] refused to add necessary features such as [[virtual memory]] to the [[IBM System/360\|System 360]]). The [[Dartmouth Time Sharing System]], where [[BASIC]] was developed, also ran on the GE-635.		The '''GE-635''' was a [[transistor]] [[mainframe]] computer; the largest of the [[GE 600 series‎]] family. It is notable mostly for being the design base of the [[GE-645]], a descendant created for the [[Multics]] project (after [[International Business Machines\|IBM]] refused to add necessary features such as [[virtual memory]] to the [[IBM System/360\|System 360]]). The [[Dartmouth Time Sharing System]], where [[BASIC]] was developed, also eventually ran on the GE-635.

	The basic overall [[architecture]] of the GE-635 was inherited by the later Multics systems: it was a [[tightly-coupled]] [[multi-processor]], with all the [[Central Processing Unit\|CPUs]] sharing access to a collection of [[multi-port memory]] modules. [[Input/output\|I/O]] activities were handled by Input/Output Controller modules, similarly sharing access to the memory modules.		The basic overall [[architecture]] of the GE-635 was inherited by the later Multics systems: it was a [[tightly-coupled]] [[multi-processor]], with all the [[Central Processing Unit\|CPUs]] sharing access to a collection of [[multi-port memory]] modules. [[Input/output\|I/O]] activities were handled by Input/Output Controller modules, similarly sharing access to the memory modules.

	The GE-635 was intended for [[multi-tasking\|multi-programming]]; a CPU operated in either Master mode, in which there were no limitations on its operation, or Slave mode, in which [[base and bounds]] type [[memory management]] applied.		The GE-635 was intended for [[multi-tasking\|multi-programming]]; a CPU operated in either 'Master' mode, in which there were no limitations on its operation, or 'Slave' mode, in which [[base and bounds]] type [[memory management]] applied.

	The GE-635 was a 36-bit machine, as was common for scientific computers in that period. The CPU included a single double-width [[register\|accumulator]], and eight [[index register]]s (18 bits wide; the size of [[address]]es in the GE-635). The [[Program Counter]] was also 18 bits.		The GE-635 was a 36-bit machine, as was common for scientific computers in that period. The CPU included a single double-width [[register\|accumulator]], and eight [[index register]]s (18 bits wide; the size of [[address]]es in the GE-635). The [[Program Counter]] was also 18 bits.