A stored-program computer is a
computer
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations ( computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These prog ...
that stores
program instructions in electronically or optically accessible memory. This contrasts with systems that stored the program instructions with
plugboards or similar mechanisms.
The definition is often extended with the requirement that the treatment of programs and data in memory be interchangeable or uniform.
Description
In principle, stored-program computers have been designed with various architectural characteristics. A computer with a
von Neumann architecture
The von Neumann architecture — also known as the von Neumann model or Princeton architecture — is a computer architecture based on a 1945 description by John von Neumann, and by others, in the '' First Draft of a Report on the EDVAC''. T ...
stores program data and instruction data in the same memory, while a computer with a
Harvard architecture
The Harvard architecture is a computer architecture with separate storage and signal pathways for instructions and data. It contrasts with the von Neumann architecture, where program instructions and data share the same memory and pathway ...
has separate memories for storing program and data.
However, the term ''stored-program computer'' is sometimes used as a synonym for the von Neumann architecture.
Jack Copeland considers that it is "historically inappropriate, to refer to electronic stored-program digital computers as 'von Neumann machines'". Hennessy and Patterson wrote that the early Harvard machines were regarded as "reactionary by the advocates of stored-program computers".
History
The concept of the stored-program computer can be traced back to the 1936 theoretical concept of a
universal Turing machine.
Von Neumann was aware of this paper, and he impressed it on his collaborators.
Many early computers, such as the
Atanasoff–Berry computer, were not reprogrammable. They executed a single hardwired program. As there were no program instructions, no program storage was necessary. Other computers, though programmable, stored their programs on
punched tape
Five- and eight-hole punched paper tape
Paper tape reader on the Harwell computer with a small piece of five-hole tape connected in a circle – creating a physical program loop
Punched tape or perforated paper tape is a form of data storage ...
, which was physically fed into the system as needed.
In 1936,
Konrad Zuse
Konrad Ernst Otto Zuse (; 22 June 1910 – 18 December 1995) was a German civil engineer, pioneering computer scientist, inventor and businessman. His greatest achievement was the world's first programmable computer; the functional program- ...
anticipated in two patent applications that machine instructions could be stored in the same storage used for data.
The
University of Manchester
The University of Manchester is a public university, public research university in Manchester, England. The main campus is south of Manchester city centre, Manchester City Centre on Wilmslow Road, Oxford Road. The university owns and operates majo ...
's
Baby is generally recognized as world's first electronic computer that ran a stored program—an event that occurred on 21 June 1948.
However the Baby was not regarded as a full-fledged computer, but more a
proof of concept predecessor to the
Manchester Mark 1 computer, which was first put to research work in April 1949. On 6 May 1949 the
EDSAC in Cambridge ran its first program, making it another electronic digital stored-program computer.
It is sometimes claimed that the
IBM SSEC, operational in January 1948, was the first stored-program computer;
this claim is controversial, not least because of the hierarchical memory system of the SSEC, and because some aspects of its operations, like access to relays or tape drives, were determined by plugging. The first stored-program computer to be built in continental Europe was the
MESM
MESM ( Ukrainian: MEOM, Мала Електронна Обчислювальна Машина; Russian: МЭСМ, Малая Электронно-Счетная Машина; 'Small Electronic Calculating Machine') was the first universally program ...
, completed in the
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...
in 1950.
The first stored-program computers
Several computers could be considered the first stored-program computer, depending on the criteria.
*
IBM SSEC, became operational in January 1948 but was
electromechanical
* In April 1948, modifications were completed to
ENIAC to function as a stored-program computer, with the program stored by setting dials in its function tables, which could store 3,600 decimal digits for instructions. It ran its first stored program on April 12, 1948 and its first production program on April 17
*
ARC2
ARC may refer to:
Business
* Aircraft Radio Corporation, a major avionics manufacturer from the 1920s to the '50s
* Airlines Reporting Corporation, an airline-owned company that provides ticket distribution, reporting, and settlement services
* ...
, a relay machine developed by
Andrew Booth and
Kathleen Booth at
Birkbeck, University of London, officially came online on 12 May 1948.
It featured the first
rotating drum storage device.
*
Manchester Baby, a developmental, fully electronic computer that successfully ran a stored program on 21 June 1948. It was subsequently developed into the
Manchester Mark 1, which ran its first program in early April 1949.
*
Electronic Delay Storage Automatic Calculator, EDSAC, which ran its first programs on 6 May 1949, and became a full-scale operational computer.
*
EDVAC, conceived in June 1945 in ''
First Draft of a Report on the EDVAC'', but not delivered until August 1949.
*
BINAC, delivered to a customer on 22 August 1949. It worked at the factory but there is disagreement about whether or not it worked satisfactorily after being delivered. If it had been finished at the projected time, it would have been the first stored-program computer in the world. It was the first stored-program computer in the U.S.
*
Manchester University Transistor Computer, is generally regarded as the first transistor-based stored-program computer having become operational in November 1953.
[ T Kilburn, R L Grimsdale and D C Webb (1956)]
''A transistor digital computer with a magnetic drum store''
CambridgProc. IEE Vol. 103, Part B, Supp. 1-3. 1956. Pages 390 – 406e University Press
Telecommunication
The concept of using a stored-program computer for switching of telecommunication circuits is called
stored program control (SPC). It was instrumental to the development of the first
electronic switching systems by
American Telephone and Telegraph (AT&T) in the
Bell System, a development that started in earnest by c. 1954 with initial concept designs by
Erna Schneider Hoover
Erna Schneider Hoover (born June 19, 1926) is an American mathematician notable for inventing a computerized telephone switching method which "revolutionized modern communication" according to several reports. It prevented system overloads by mon ...
at
Bell Labs
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984),
then AT&T Bell Laboratories (1984–1996)
and Bell Labs Innovations (1996–2007),
is an American industrial research and scientific development company owned by mul ...
. The first of such systems was installed on a trial basis in
Morris, Illinois in 1960. The storage medium for the program instructions was the
flying-spot store, a
photographic plate read by an optical scanner that had a speed of about one microsecond access time.
[''Electronic Central Office'', Long Lines 40(5) p16 (1960)] For temporary data, the system used a barrier-grid electrostatic
storage tube.
See also
*
Stored program control
References
{{Reflist, 30em
Classes of computers
Department of Computer Science, University of Manchester
Discovery and invention controversies