ACE (computer)
Encyclopedia
The Automatic Computing Engine (ACE) was an early electronic stored-program computer
design produced by Alan Turing
at the invitation of John R. Womersley
, superintendent of the Mathematics Division of the National Physical Laboratory
(NPL). The use of the word Engine was in homage to Charles Babbage
and his Difference Engine
and Analytical Engine
. Turing's technical design Proposed Electronic Calculator was the product of his theoretical work in 1936 "On Computable Numbers" and his wartime experience at Bletchley Park
where the Colossus computers had been successful in breaking German military codes. In his 1936 paper, Turing described his idea as a "universal computing machine", but it is now known as the Universal Turing machine
.
On 19 February 1946 Turing presented a detailed paper to the National Physical Laboratory (NPL)
Executive Committee, giving the first reasonably complete design of a stored-program computer. However, because of the strict and long-lasting secrecy around the Bletchley Park work, he was prohibited (because of the Official Secrets Act
) from explaining that he knew that his ideas could be implemented in an electronic device. The better-known EDVAC
design presented in the First Draft of a Report on the EDVAC
(dated June 30, 1945), by John von Neumann
, who knew of Turing's theoretical work, received much publicity, despite its incomplete nature and questionable lack of attribution of the sources of some of the ideas.
Turing's report on the ACE was written in late 1945 and included detailed logical circuit diagrams and a cost estimate of ₤11,200. He felt that speed and size of memory
were crucial and he proposed a high-speed memory of what would today be called 25 KiB
, accessed at a speed of 1 MHz
. The ACE implemented subroutine calls, whereas the EDVAC did not, and what also set the ACE apart from the EDVAC was the use of Abbreviated Computer Instructions, an early form of programming language. Initially, it was planned that Tommy Flowers
, the engineer at the Post Office Research Station
at Dollis Hill
in north London, who had been responsible for building the Colossus computers should build the ACE, but because of the secrecy around his wartime achievements and the pressure of post-war work, this was not possible.
Turing's colleagues at the NPL, not knowing about Colossus, thought that the engineering work to build a complete ACE was too ambitious, so the first version of the ACE that was built was the Pilot Model ACE
, a smaller version of Turing's original design. The Pilot ACE had 1450 thermionic valves (vacuum tubes), and used mercury delay lines
for its main memory. Each of the 12 delay lines could store 32 instructions or data words of 32 bits. This ran its first program on May 10, 1950, at which time it was the fastest computer in the world with a clock speed
of 1MHz.
A second implementation of the ACE design was the MOSAIC (Ministry of Supply Automatic Integrator and Computer). This was built by Allen Coombs and William Chandler of Dollis Hill who had worked with Tommy Flowers
on building the ten Colossus computers. It was installed at the Telecommunications Research Establishment
(TRE) which soon became the Royal Radar Establishment
(RRE) at Malvern and ran its first program in late 1952 or early 1953. It was used to calculate aircraft trajectories from radar data, but details of it are still secret.
The principles of the ACE design were used in the Bendix Corporation's
G-15
computer. The engineering design was done by Harry Huskey
who had spent 1947 in the ACE section at the NPL. He later contributed to the hardware designs for the EDVAC. The first G-15 ran in 1954 and, as a relatively small single user machine, some consider it to be the first personal computer
.
The first production versions of the Pilot ACE, the English Electric DEUCE
, of which 31 were sold, were delivered in the spring of 1955.
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...
design produced by Alan Turing
Alan Turing
Alan Mathison Turing, OBE, FRS , was an English mathematician, logician, cryptanalyst, and computer scientist. He was highly influential in the development of computer science, providing a formalisation of the concepts of "algorithm" and "computation" with the Turing machine, which played a...
at the invitation of John R. Womersley
John R. Womersley
John Ronald Womersley was a British mathematician who made important contributions to textiles, computing and arterial mechanics . He studied mathematics at Imperial College of Science and Technology and subsequently worked at the Shirley Institute Manchester...
, superintendent of the Mathematics Division of the National Physical Laboratory
National Physical Laboratory, UK
The National Physical Laboratory is the national measurement standards laboratory for the United Kingdom, based at Bushy Park in Teddington, London, England. It is the largest applied physics organisation in the UK.-Description:...
(NPL). The use of the word Engine was in homage to Charles Babbage
Charles Babbage
Charles Babbage, FRS was an English mathematician, philosopher, inventor and mechanical engineer who originated the concept of a programmable computer...
and his Difference Engine
Difference engine
A difference engine is an automatic, mechanical calculator designed to tabulate polynomial functions. Both logarithmic and trigonometric functions can be approximated by polynomials, so a difference engine can compute many useful sets of numbers.-History:...
and Analytical Engine
Analytical engine
The Analytical Engine was a proposed mechanical general-purpose computer designed by English mathematician Charles Babbage. It was first described in 1837 as the successor to Babbage's difference engine, a design for a mechanical calculator...
. Turing's technical design Proposed Electronic Calculator was the product of his theoretical work in 1936 "On Computable Numbers" and his wartime experience at Bletchley Park
Bletchley Park
Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
where the Colossus computers had been successful in breaking German military codes. In his 1936 paper, Turing described his idea as a "universal computing machine", but it is now known as the Universal Turing machine
Universal Turing machine
In computer science, a universal Turing machine is a Turing machine that can simulate an arbitrary Turing machine on arbitrary input. The universal machine essentially achieves this by reading both the description of the machine to be simulated as well as the input thereof from its own tape. Alan...
.
On 19 February 1946 Turing presented a detailed paper to the National Physical Laboratory (NPL)
National Physical Laboratory, UK
The National Physical Laboratory is the national measurement standards laboratory for the United Kingdom, based at Bushy Park in Teddington, London, England. It is the largest applied physics organisation in the UK.-Description:...
Executive Committee, giving the first reasonably complete design of a stored-program computer. However, because of the strict and long-lasting secrecy around the Bletchley Park work, he was prohibited (because of the Official Secrets Act
Official Secrets Act
The Official Secrets Act is a stock short title used in the United Kingdom, Ireland, India and Malaysia and formerly in New Zealand for legislation that provides for the protection of state secrets and official information, mainly related to national security.-United Kingdom:*The Official Secrets...
) from explaining that he knew that his ideas could be implemented in an electronic device. The better-known EDVAC
EDVAC
EDVAC was one of the earliest electronic computers. Unlike its predecessor the ENIAC, it was binary rather than decimal, and was a stored program computer....
design presented in the First Draft of a Report on the EDVAC
First Draft of a Report on the EDVAC
The First Draft of a Report on the EDVAC was an incomplete 101-page document written by John von Neumann and distributed on June 30, 1945 by Herman Goldstine, security officer on the classified ENIAC project...
(dated June 30, 1945), by John von Neumann
John von Neumann
John von Neumann was a Hungarian-American mathematician and polymath who made major contributions to a vast number of fields, including set theory, functional analysis, quantum mechanics, ergodic theory, geometry, fluid dynamics, economics and game theory, computer science, numerical analysis,...
, who knew of Turing's theoretical work, received much publicity, despite its incomplete nature and questionable lack of attribution of the sources of some of the ideas.
Turing's report on the ACE was written in late 1945 and included detailed logical circuit diagrams and a cost estimate of ₤11,200. He felt that speed and size of memory
Computer memory
In computing, memory refers to the physical devices used to store programs or data on a temporary or permanent basis for use in a computer or other digital electronic device. The term primary memory is used for the information in physical systems which are fast In computing, memory refers to the...
were crucial and he proposed a high-speed memory of what would today be called 25 KiB
Kibibyte
The kibibyte is a multiple of the unit byte for quantities of digital information. The binary prefix kibi means 1024; therefore, 1 kibibyte is . The unit symbol for the kibibyte is KiB. The unit was established by the International Electrotechnical Commission in 1999 and has been accepted for use...
, accessed at a speed of 1 MHz
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
. The ACE implemented subroutine calls, whereas the EDVAC did not, and what also set the ACE apart from the EDVAC was the use of Abbreviated Computer Instructions, an early form of programming language. Initially, it was planned that Tommy Flowers
Tommy Flowers
Thomas "Tommy" Harold Flowers, MBE was an English engineer. During World War II, Flowers designed Colossus, the world's first programmable electronic computer, to help solve encrypted German messages.-Early life:...
, the engineer at the Post Office Research Station
Post Office Research Station
The Post Office Research Station at Dollis Hill, London, was first established in 1921 and opened by Prime Minister Ramsay MacDonald in 1933.In 1943 the world's first programmable electronic computer, Colossus Mark 1 was built by Tommy Flowers and his team, followed in 1944 and 1945 by nine...
at Dollis Hill
Dollis Hill
Dollis Hill is an area of north-west London. It lies close to Willesden, in the London Borough of Brent. As a result, Dollis Hill is sometimes referred as being part of Willesden, especially by the national press...
in north London, who had been responsible for building the Colossus computers should build the ACE, but because of the secrecy around his wartime achievements and the pressure of post-war work, this was not possible.
Turing's colleagues at the NPL, not knowing about Colossus, thought that the engineering work to build a complete ACE was too ambitious, so the first version of the ACE that was built was the Pilot Model ACE
Pilot ACE
The Pilot ACE was one of the first computers built in the United Kingdom, at the National Physical Laboratory in the early 1950s.It was a preliminary version of the full ACE, which had been designed by Alan Turing. After Turing left NPL , James H...
, a smaller version of Turing's original design. The Pilot ACE had 1450 thermionic valves (vacuum tubes), and used mercury delay lines
Delay line memory
Delay line memory was a form of computer memory used on some of the earliest digital computers. Like many modern forms of electronic computer memory, delay line memory was a refreshable memory, but as opposed to modern random-access memory, delay line memory was serial-access...
for its main memory. Each of the 12 delay lines could store 32 instructions or data words of 32 bits. This ran its first program on May 10, 1950, at which time it was the fastest computer in the world with a clock speed
Clock rate
The clock rate typically refers to the frequency that a CPU is running at.For example, a crystal oscillator frequency reference typically is synonymous with a fixed sinusoidal waveform, a clock rate is that frequency reference translated by electronic circuitry into a corresponding square wave...
of 1MHz.
A second implementation of the ACE design was the MOSAIC (Ministry of Supply Automatic Integrator and Computer). This was built by Allen Coombs and William Chandler of Dollis Hill who had worked with Tommy Flowers
Tommy Flowers
Thomas "Tommy" Harold Flowers, MBE was an English engineer. During World War II, Flowers designed Colossus, the world's first programmable electronic computer, to help solve encrypted German messages.-Early life:...
on building the ten Colossus computers. It was installed at the Telecommunications Research Establishment
Telecommunications Research Establishment
The Telecommunications Research Establishment was the main United Kingdom research and development organization for radio navigation, radar, infra-red detection for heat seeking missiles, and related work for the Royal Air Force during World War II and the years that followed. The name was...
(TRE) which soon became the Royal Radar Establishment
Royal Radar Establishment
The name Royal Radar Establishment was given to the existing Radar Research Establishment following a visit by Queen Elizabeth II in 1957. Both names were abbreviated to RRE. The establishment had been formed, under its first name, in 1953 by merging the Telecommunications Research Establishment ...
(RRE) at Malvern and ran its first program in late 1952 or early 1953. It was used to calculate aircraft trajectories from radar data, but details of it are still secret.
The principles of the ACE design were used in the Bendix Corporation's
Bendix Corporation
The Bendix Corporation was an American manufacturing and engineering company which during various times in its 60 year existence made brake systems, aeronautical hydraulics, avionics, aircraft and automobile fuel control systems, radios, televisions and computers, and which licensed its name for...
G-15
Bendix G-15
The Bendix G-15 computer was introduced in 1956 by the Bendix Corporation, Computer Division, Los Angeles, California. It was about 5 by 3 by 3 ft and weighed about 950 lb . The base system, without peripherals, cost $49,500. A working model cost around $60,000. It could also be rented for...
computer. The engineering design was done by Harry Huskey
Harry Huskey
Harry Douglas Huskey is an American computer designer pioneer.Huskey was born in the Smoky Mountains region of North Carolina and grew up in Idaho. He gained his Master's and then his PhD in 1943 from the Ohio State University on Contributions to the Problem of Geocze...
who had spent 1947 in the ACE section at the NPL. He later contributed to the hardware designs for the EDVAC. The first G-15 ran in 1954 and, as a relatively small single user machine, some consider it to be the first personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
.
The first production versions of the Pilot ACE, the English Electric DEUCE
English Electric DEUCE
The DEUCE was one of the earliest British commercially available computers, built by English Electric from 1955.It was the production version of the Pilot ACE, itself a cut down version of Alan Turing's ACE....
, of which 31 were sold, were delivered in the spring of 1955.
External links
- * Oral history interview with Donald W. Davies, Charles Babbage InstituteCharles Babbage InstituteThe Charles Babbage Institute is a research center at the University of Minnesota specializing in the history of information technology, particularly the history since 1935 of digital computing, programming/software, and computer networking....
, University of Minnesota. Davies describes computer projects at the U.K. National Physical Laboratory, from the 1947 design work of Alan TuringAlan TuringAlan Mathison Turing, OBE, FRS , was an English mathematician, logician, cryptanalyst, and computer scientist. He was highly influential in the development of computer science, providing a formalisation of the concepts of "algorithm" and "computation" with the Turing machine, which played a...
to the development of the two ACE computers. Davies discusses a much larger, second ACE, and the decision to contract with English ElectricEnglish ElectricEnglish Electric was a British industrial manufacturer. Founded in 1918, it initially specialised in industrial electric motors and transformers...
Company to build the DEUCEEnglish Electric DEUCEThe DEUCE was one of the earliest British commercially available computers, built by English Electric from 1955.It was the production version of the Pilot ACE, itself a cut down version of Alan Turing's ACE....
-- possibly the first commercially produced computer in Great Britain. - Events in the history of NPL — ACE computer