EDSAC - Revision history

Jnc: /* Further reading */ +Faster Than Thought

2026-09-27T21:43:46Z

Jnc: Better word

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Better word

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	The '''Electronic Delay Storage Automatic Calculator''' (usually referred to by the acronym, '''EDSAC''') was a very early [[electronic]] [[computer]]; it was built at Cambridge University by a team led by [[Maurice Wilkes]]. It was initially conceived in 1946, as he was attending the [[Moore School Lectures]] in July-August that year; the machine did its first calculation on 6 May, 1949.		The '''Electronic Delay Storage Automatic Calculator''' (usually referred to by the acronym, '''EDSAC''') was a very early [[electronic]] [[computer]]; it was built at Cambridge University by a team led by [[Maurice Wilkes]]. It was initially conceived in 1946, as he was attending the [[Moore School Lectures]] in July-August that year; the machine did its first calculation on 6 May, 1949.

	It was a [[serial computer]] internally, built out of [[vacuum tube]]s, with mercury [[delay line]] [[main memory]] - a technology proposed at the Moore School Lectures. Experimentation with that technology started back at Cambridge in January, 1947; construction of the complete main memory ~~happened~~ around December, 1947.		It was a [[serial computer]] internally, built out of [[vacuum tube]]s, with mercury [[delay line]] [[main memory]] - a technology proposed at the Moore School Lectures. Experimentation with that technology started back at Cambridge in January, 1947; construction of the complete main memory occurred around December, 1947.

	Starting in November, 1947, personnel from the [[LEO]] project helped with the construction, learning about the field, for use in their own project; they also provided some funding for the construction of EDSAC.		Starting in November, 1947, personnel from the [[LEO]] project helped with the construction, learning about the field, for use in their own project; they also provided some funding for the construction of EDSAC.

Jnc: Add a short account of its construction

2026-09-16T01:35:13Z

Add a short account of its construction

← Older revision		Revision as of 01:35, 16 September 2026
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	The '''Electronic Delay Storage Automatic Calculator''' (usually referred to by the acronym, '''EDSAC''') was a very early computer; a [[serial computer]] internally, built out of [[vacuum tube]]s, with mercury [[delay line]] [[main memory]]. ~~It was conceived~~ in ~~1946~~, ~~and~~ the ~~machine did its first calculation~~ in the ~~summer~~ of ~~1949~~.		The '''Electronic Delay Storage Automatic Calculator''' (usually referred to by the acronym, '''EDSAC''') was a very early [[electronic]] [[computer]]; it was built at Cambridge University by a team led by [[Maurice Wilkes]]. It was initially conceived in 1946, as he was attending the [[Moore School Lectures]] in July-August that year; the machine did its first calculation on 6 May, 1949.

			It was a [[serial computer]] internally, built out of [[vacuum tube]]s, with mercury [[delay line]] [[main memory]] - a technology proposed at the Moore School Lectures. Experimentation with that technology started back at Cambridge in January, 1947; construction of the complete main memory happened around December, 1947.

			Starting in November, 1947, personnel from the [[LEO]] project helped with the construction, learning about the field, for use in their own project; they also provided some funding for the construction of EDSAC.

	==Operation==		==Operation==

	The action of the machine proceeds in two stages; in stage I an order passes from the store into the control unit; in stage II the order is executed. The machine then proceeds automatically to repeat stage I, in general taking the order from the storage location following that containing the order just executed. (add exception note here) Each order calls for one simple operation to be performed; for example, it may cause some number to be extracted from the store and added to whatever happens to be in the accumulator, the sum being left in the accumulator, or it may cause the contents of the accumulator to be ~~transfered~~ to the store. Some orders, for example left or right shift orders, do not involve the use of the store at all.		The action of the machine proceeds in two stages; in stage I an order ([[instruction]]) passes from the store into the control unit; in stage II the order is executed. The machine then proceeds automatically to repeat stage I, in general taking the order from the storage location following that containing the order just executed. (add exception note here) Each order calls for one simple operation to be performed; for example, it may cause some number to be extracted from the store and added to whatever happens to be in the [[accumulator]], the sum being left in the accumulator, or it may cause the contents of the accumulator to be transferred to the store. Some orders, for example left or right shift orders, do not involve the use of the store at all.

	There are in the EDSAC code eighteen orders from which the programmer can build up ~~his~~ program. They are written in the form of a letter indicating the function of the order, and a number (the address) specifying the location (if any) in the store concerned. The address is followed by the code letter F if it refers to a short storage location, and by the code letter D if it refers to a long storage location, The full order code for the EDSAC is as follows:		There are in the EDSAC code eighteen orders from which the programmer can build up their program. They are written in the form of a letter indicating the function of the order, and a number (the [[address]]) specifying the location (if any) in the store concerned. The address is followed by the code letter F if it refers to a short storage location, and by the code letter D if it refers to a long storage location, The full order code for the EDSAC is as follows:

	==Order Code==		===Order Code===

	Where the code letter terminating an order is not shown it may be either F or D.		Where the code letter terminating an order is not shown it may be either F or D.
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	==Further reading==		==Further reading==

	* Maurice Wilkes, David Wheeler, Stanley Gill, ''The Preparation of Programs for an Electronic Digital Computer'', Addison-Wesley, Cambridge, 1951 - the very first book ever published about programming		* Maurice Wilkes, ''Memoirs of a Computer Pioneer'', MIT Press, Cambridge, 1985 - chapters 13 and 14 cover the origin and construction of EDSAC
	* Maurice Wilkes, ''Memoirs of a Computer Pioneer'', MIT Press, Cambridge, 1985 - chapters 13 and 14 cover the EDSAC
	* Brian Randell (editor), [https://link.springer.com/book/10.1007/978-3-642-96145-8 ''The Origins of Digital Computers: Selected Papers''], Springer-Verlag, Berlin, Heidelberg, New York, 1973, 1982 (3rd edition) - EDSAC is covered in the last sections of Chapter VIII		* Brian Randell (editor), [https://link.springer.com/book/10.1007/978-3-642-96145-8 ''The Origins of Digital Computers: Selected Papers''], Springer-Verlag, Berlin, Heidelberg, New York, 1973, 1982 (3rd edition) - EDSAC is covered in the last sections of Chapter VIII
	* Nicholas Metropolis, Jack Howlett, Gian-Carlo Rota (editors), [https://www.sciencedirect.com/book/9780124916500/a-history-of-computing-in-the-twentieth-century ''A History of Computing in the Twentieth Century''], Academic Press, New York, 1980 - EDSAC is covered in the last section of Part IV		* Nicholas Metropolis, Jack Howlett, Gian-Carlo Rota (editors), [https://www.sciencedirect.com/book/9780124916500/a-history-of-computing-in-the-twentieth-century ''A History of Computing in the Twentieth Century''], Academic Press, New York, 1980 - EDSAC is covered in the last section of Part IV
			* Maurice Wilkes, David Wheeler, Stanley Gill, ''The Preparation of Programs for an Electronic Digital Computer'', Addison-Wesley, Cambridge, 1951 - the very first book ever published about programming
	* Raúl Rojas, Ulf Hashagen (editors), ''The First Computers: History and Architectures'', MIT Press, Cambridge, 2002 - the last chapter in part IV covers an EDSAC [[simulator]]		* Raúl Rojas, Ulf Hashagen (editors), ''The First Computers: History and Architectures'', MIT Press, Cambridge, 2002 - the last chapter in part IV covers an EDSAC [[simulator]]

Jnc: /* External links */ +The EDSAC Order Code: Explanatory Notes

2025-09-25T10:34:40Z

External links: +The EDSAC Order Code: Explanatory Notes

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	* [http://www.vintage-icl-computers.com/EDSAC EDSAC]		* [http://www.vintage-icl-computers.com/EDSAC EDSAC]
			* [https://www.cl.cam.ac.uk/relics/orders.notes.html The EDSAC Order Code: Explanatory Notes] - some notes from David Wheeler
	* [http://www.cs.man.ac.uk/CCS/res/res02.htm#c The thinking behind EDSAC] - personal memories from Maurice Wilkes		* [http://www.cs.man.ac.uk/CCS/res/res02.htm#c The thinking behind EDSAC] - personal memories from Maurice Wilkes
	* [https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/calculating-devices/edsac-and-computing-cambridge The EDSAC and Computing in Cambridge]		* [https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/calculating-devices/edsac-and-computing-cambridge The EDSAC and Computing in Cambridge]

Jnc: +The EDSAC and Computing in Cambridge

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+The EDSAC and Computing in Cambridge

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	* [http://www.vintage-icl-computers.com/EDSAC EDSAC]		* [http://www.vintage-icl-computers.com/EDSAC EDSAC]
	* [http://www.cs.man.ac.uk/CCS/res/res02.htm#c - The thinking behind EDSAC] - personal memories from Maurice Wilkes		* [http://www.cs.man.ac.uk/CCS/res/res02.htm#c The thinking behind EDSAC] - personal memories from Maurice Wilkes
			* [https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/calculating-devices/edsac-and-computing-cambridge The EDSAC and Computing in Cambridge]

	[[Category: Early Computers]]		[[Category: Early Computers]]
	[[Category: Unique Computers]]		[[Category: Unique Computers]]

Jnc: /* External links */ +The thinking behind EDSAC

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External links: +The thinking behind EDSAC

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	* [http://www.vintage-icl-computers.com/EDSAC EDSAC]		* [http://www.vintage-icl-computers.com/EDSAC EDSAC]
			* [http://www.cs.man.ac.uk/CCS/res/res02.htm#c - The thinking behind EDSAC] - personal memories from Maurice Wilkes

	[[Category: Early Computers]]		[[Category: Early Computers]]
	[[Category: Unique Computers]]		[[Category: Unique Computers]]

Jnc: Add a few details; +further reading

2024-01-08T13:27:00Z

Add a few details; +further reading

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-The '''Electronic Delay Storage Automatic Calculator''' (usually referred to by the acronym, '''EDSAC''') was conceived in 1946, the machine did its first calculation in the summer of 1949.
+The '''Electronic Delay Storage Automatic Calculator''' (usually referred to by the acronym, '''EDSAC''') was a very early computer; a [[serial computer]] internally, built out of [[vacuum tube]]s, with mercury [[delay line]] [[main memory]]. It was conceived in 1946, and the machine did its first calculation in the summer of 1949.
 ==Operation==
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 {{semi-stub}}
 [[Category: Early Computers]]
-[[Category: Mainframes]]
+[[Category: Unique Computers]]

Jnc: +New cat

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+New cat

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

			[[Category: Early Computers]]
	[[Category: Mainframes]]		[[Category: Mainframes]]

Jnc: fmt, better cat

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fmt, better cat

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	~~EDSAC~~ Electronic Delay Storage Automatic Calculator was conceived in 1946, the machine did its first calculation in the summer of 1949		The '''Electronic Delay Storage Automatic Calculator''' (usually referred to by the acronym, '''EDSAC''') was conceived in 1946, the machine did its first calculation in the summer of 1949.

	~~The EDSAC order code~~		==Operation==

	The action of the machine proceeds in two stages; in stage I an order passes from the store into the control unit; in stage II the order is executed. The machine then proceeds automatically to repeat stage I, in general taking the order from the storage location following that containing the order just executed. (add exception note here) Each		The action of the machine proceeds in two stages; in stage I an order passes from the store into the control unit; in stage II the order is executed. The machine then proceeds automatically to repeat stage I, in general taking the order from the storage location following that containing the order just executed. (add exception note here) Each order calls for one simple operation to be performed; for example, it may cause some number to be extracted from the store and added to whatever happens to be in the accumulator, the sum being left in the accumulator, or it may cause the contents of the accumulator to be transfered to the store. Some orders, for example left or right shift orders, do not involve the use of the store at all.
	order calls for one simple operation to be performed; for example, it may cause some number to be extracted from the store and added to whatever happens to be in the accumulator, the sum being left in the accumulator, or it may cause the contents of the accumulator to be transfered to the store. Some orders, for example left or right shift orders, do not involve the use of the store at all.

	There are in the EDSAC code eighteen orders from which the programmer can build up his program. They are written in the form of a letter indicating the function of the order, and a number (the address) specifying the location (if any) in the store concerned. The address is followed by the code letter F if it refers to a short storage location, and by the code letter D if it refers to a long storage location, The full order code for the EDSAC is as follows:		There are in the EDSAC code eighteen orders from which the programmer can build up his program. They are written in the form of a letter indicating the function of the order, and a number (the address) specifying the location (if any) in the store concerned. The address is followed by the code letter F if it refers to a short storage location, and by the code letter D if it refers to a long storage location, The full order code for the EDSAC is as follows:

	~~'''~~Order Code~~'''~~		==Order Code==

	Where the code letter terminating an order is not shown it may be either F or D.		Where the code letter terminating an order is not shown it may be either F or D.
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	{{semi-stub}}		{{semi-stub}}

	[[Category:~~Computers~~]]		[[Category: Mainframes]]

Jnc: -semist

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-semist

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	** The addresses in these orders may be k.2<sup>p-1</sup> where k is odd, provided that the addresses do not exceed 2047.		** The addresses in these orders may be k.2<sup>p-1</sup> where k is odd, provided that the addresses do not exceed 2047.

			{{semi-stub}}



	{{stub}}

	[[Category:Computers]]		[[Category:Computers]]

← Older revision		Revision as of 21:43, 27 September 2026
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	* Brian Randell (editor), [https://link.springer.com/book/10.1007/978-3-642-96145-8 ''The Origins of Digital Computers: Selected Papers''], Springer-Verlag, Berlin, Heidelberg, New York, 1973, 1982 (3rd edition) - EDSAC is covered in the last sections of Chapter VIII		* Brian Randell (editor), [https://link.springer.com/book/10.1007/978-3-642-96145-8 ''The Origins of Digital Computers: Selected Papers''], Springer-Verlag, Berlin, Heidelberg, New York, 1973, 1982 (3rd edition) - EDSAC is covered in the last sections of Chapter VIII
	* Nicholas Metropolis, Jack Howlett, Gian-Carlo Rota (editors), [https://www.sciencedirect.com/book/9780124916500/a-history-of-computing-in-the-twentieth-century ''A History of Computing in the Twentieth Century''], Academic Press, New York, 1980 - EDSAC is covered in the last section of Part IV		* Nicholas Metropolis, Jack Howlett, Gian-Carlo Rota (editors), [https://www.sciencedirect.com/book/9780124916500/a-history-of-computing-in-the-twentieth-century ''A History of Computing in the Twentieth Century''], Academic Press, New York, 1980 - EDSAC is covered in the last section of Part IV
			* B. V. Bowden (editor), ''Faster Than Thought: A Symposium on Digital Computing Machines'', Pitman Publishing, New York, 1964 - the EDSAC is briefly covered in Chapter 7, pp. 130-134
	* Maurice Wilkes, David Wheeler, Stanley Gill, ''The Preparation of Programs for an Electronic Digital Computer'', Addison-Wesley, Cambridge, 1951 - the very first book ever published about programming		* Maurice Wilkes, David Wheeler, Stanley Gill, ''The Preparation of Programs for an Electronic Digital Computer'', Addison-Wesley, Cambridge, 1951 - the very first book ever published about programming
	* Raúl Rojas, Ulf Hashagen (editors), ''The First Computers: History and Architectures'', MIT Press, Cambridge, 2002 - the last chapter in part IV covers an EDSAC [[simulator]]		* Raúl Rojas, Ulf Hashagen (editors), ''The First Computers: History and Architectures'', MIT Press, Cambridge, 2002 - the last chapter in part IV covers an EDSAC [[simulator]]