SEAC (''Standards Eastern Automatic Computer'' or ''Standards Electronic Automatic Computer'') was a first-generation electronic

computer A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...

, built in 1950 by the

U.S. The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous ...

National Bureau of Standards The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sc ...

(NBS) and was initially called the ''National Bureau of Standards Interim Computer'', because it was a small-scale computer designed to be built quickly and put into operation while the NBS waited for more powerful computers to be completed (the DYSEAC). The team that developed SEAC was led by Samuel N. Alexander and Ralph J. Slutz. SEAC was demonstrated in April 1950 and was dedicated in June 1950; it is claimed to be the first fully operational stored-program electronic computer in the US.

Description

Based on

EDVAC EDVAC (Electronic Discrete Variable Automatic Computer) was one of the earliest electronic computers. It was built by Moore School of Electrical Engineering at the University of Pennsylvania. Along with ORDVAC, it was a successor to the ENIAC. ...

, SEAC used only 747

vacuum tube A vacuum tube, electron tube, thermionic valve (British usage), or tube (North America) is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied. It ...

s (a small number for the time) eventually expanded to 1,500 tubes. It had 10,500

germanium Germanium is a chemical element; it has Symbol (chemistry), symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid or a nonmetal in the carbon group that is chemically ...

diode A diode is a two-Terminal (electronics), terminal electronic component that conducts electric current primarily in One-way traffic, one direction (asymmetric electrical conductance, conductance). It has low (ideally zero) Electrical resistance ...

s which performed all of the logic functions (see the article

diode–transistor logic Diode–transistor logic (DTL) is a class of digital circuits that is the direct ancestor of transistor–transistor logic. It is called so because the logic gating functions AND and OR are performed by diode logic, while logical inversi ...

for the working principles of diode logic), later expanded to 16,000 diodes. It was the first computer to do most of its logic with solid-state devices. The tubes were used for amplification, inversion and storing information in dynamic

flip-flops Flip-flops are a type of light sandal-like shoe, typically worn as a form of casual footwear. They consist of a flat sole held loosely on the foot by a Y-shaped strap known as a toe thong that passes between the first and second toes and around ...

. The machine used 64 acoustic delay lines to store 512 words of

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembe ...

, with each word being 45 bits in size. The

clock rate Clock rate or clock speed in computing typically refers to the frequency at which the clock generator of a processor can generate pulses used to synchronize the operations of its components. It is used as an indicator of the processor's s ...

was kept low (1

MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base u ...

). The computer's instruction set consisted of only 11 types of instructions: fixed-point addition, subtraction, multiplication, and division; comparison, and input & output. It eventually expanded to 16 instructions. The addition time was 864 microseconds and the multiplication time was 2,980 microseconds (i.e. close to 3 milliseconds). Weight: (central machine).

Applications

On some occasions SEAC was used by a remote

teletype A teleprinter (teletypewriter, teletype or TTY) is an electromechanical device that can be used to send and receive typed messages through various communications channels, in both point-to-point and point-to-multipoint configurations. Init ...

. This makes it one of the first computers to be used remotely. With many modifications, it was used until 1964. Some of the problems run on it dealt with: *

digital imaging Digital imaging or digital image acquisition is the creation of a digital representation of the visual characteristics of an object, such as a physical scene or the interior structure of an object. The term is often assumed to imply or include ...

, led by Russell A. Kirsch *

computer animation Computer animation is the process used for digitally generating Film, moving images. The more general term computer-generated imagery (CGI) encompasses both still images and moving images, while computer animation refers to moving images. Virtu ...

of the city traffic simulation *

meteorology Meteorology is the scientific study of the Earth's atmosphere and short-term atmospheric phenomena (i.e. weather), with a focus on weather forecasting. It has applications in the military, aviation, energy production, transport, agricultur ...

linear programming Linear programming (LP), also called linear optimization, is a method to achieve the best outcome (such as maximum profit or lowest cost) in a mathematical model whose requirements and objective are represented by linear function#As a polynomia ...

* optical lenses * a program for

Los Alamos National Laboratory Los Alamos National Laboratory (often shortened as Los Alamos and LANL) is one of the sixteen research and development Laboratory, laboratories of the United States Department of Energy National Laboratories, United States Department of Energy ...

* tables for

LORAN LORAN (Long Range Navigation) was a hyperbolic navigation, hyperbolic radio navigation system developed in the United States during World War II. It was similar to the UK's Gee (navigation), Gee system but operated at lower frequencies in order ...

navigation * statistical sampling plans * wave function of the

helium Helium (from ) is a chemical element; it has chemical symbol, symbol He and atomic number 2. It is a colorless, odorless, non-toxic, inert gas, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling point is ...

atom * designing a

proton A proton is a stable subatomic particle, symbol , Hydron (chemistry), H+, or 1H+ with a positive electric charge of +1 ''e'' (elementary charge). Its mass is slightly less than the mass of a neutron and approximately times the mass of an e ...

synchrotron A synchrotron is a particular type of cyclic particle accelerator, descended from the cyclotron, in which the accelerating particle beam travels around a fixed closed-loop path. The strength of the magnetic field which bends the particle beam i ...

File:SEACComputer 008.jpg, SEAC block diagram File:SEACComputer 011.jpg, SEAC input/output diagram File:SEACComputer 030.jpg, Magnetic wire drives and cartridges File:SEACComputer 025.jpg, Offline magnetic wire to paper tape & print station File:SEACComputer 031.jpg, SEAC scanner File:NBSFirstScanImageRestored.jpg, First image scanned into SEAC, son of Russell A. Kirsch File:SEACComputer 018.jpg, Samuel N. Alexander with SEAC File:SEACComputer 047.jpg, Horace Joseph and George A. Moore using the SEAC image scanner to analyze metallurgical photographs in 1960. Moore was legally blind. File:SEACComputer 039.jpg, SEAC wiring File:SEACComputer 024.jpg, Ethel Marden at the control console of SEAC in 1959

References

* Williams, Michael R. (1997). ''A History of Computing Technology''. IEEE Computer Society. * Metropolis, N; Howlett, J.; Rota, Gian-Carlo (editors) (1980). ''A History of Computing in the Twentieth Century''. Academic Press. (The chapter "Memories of the Bureau of Standards' SEAC", by Ralph J. Slutz.) * Astin, A. V. (1955)
''Computer Development (SEAC and DYSEAC) at the National Bureau of Standards, Washington D.C.''
National Bureau of Standards Circular 551, Issued January 25, 1955, U.S. Government Printing Office. Includes several papers describing SEAC, its technical details, and its operation. In particular, see "SEAC", by S. Greenwald, S. N. Alexander, and Ruth C. Haueter, on pp. 5–26, for an overview of the SEAC system.

External links

SEAC and the Start of Image Processing at the National Bureau of Standards(Archived)
– At the NIST virtual museum
Margaret R. Fox Papers, 1935-1976

Charles Babbage Institute The IT History Society (ITHS) is an organization that supports the history and scholarship of information technology by encouraging, fostering, and facilitating archival and historical research. Formerly known as the Charles Babbage Foundation, ...

, University of Minnesota. collection contains reports, including the original report on the ENIAC, UNIVAC, and many early in-house National Bureau of Standards (NBS) activity reports; memoranda on and histories of SEAC, SWAC, and DYSEAC; programming instructions for the UNIVAC, LARC, and MIDAC; patent evaluations and disclosures; system descriptions; speeches and articles written by Margaret Fox's colleagues; and correspondence of Samuel Alexander, Margaret Fox, and Samuel Williams. Boxes 6-8 of the Fox papers contain documents, reports, and analysis of the NBS's SEAC.
SEAC ("Standards Eastern Automatic Computer") (1950)
from ''History of Computing: An Encyclopedia of the People and Machines that Made Computer History'', Lexikon Services Publishing
Timeline of Computer History at CHM
{{Commons category, position=left, SEAC computer One-of-a-kind computers Vacuum tube computers 1950s computers Computer-related introductions in 1950 Serial computers

Description

Applications

See also

References

Further reading

External links