EDVAC
EDVAC(Electronic Discrete Variable Automatic Computer) was one of the earliestelectroniccomputers.It was built byMoore School of Electrical Engineering,Pennsylvania.[1][2]: 626–628 Along withORDVAC,it was a successor to theENIAC.Unlike ENIAC, it wasbinaryrather thandecimal,and was designed to be astored-program computer.
ENIAC inventors,John MauchlyandJ. Presper Eckert,proposed the EDVAC's construction in August 1944. A contract to build the new computer was signed in April 1946 with an initial budget ofUS$100,000. EDVAC was delivered to theBallistic Research Laboratoryin 1949. TheBallistic Research Laboratorybecame a part of theUS Army Research Laboratoryin 1952.
Functionally, EDVAC was a binaryserial computerwith automatic addition, subtraction, multiplication, programmed division and automatic checking with anultrasonic serial memory[3]having a capacity of 1,024 44-bitwords.EDVAC's average addition time was 864microsecondsand its average multiplication time was 2,900 microseconds.
Project and plan
[edit]ENIAC inventors John Mauchly and J. Presper Eckert proposed EDVAC's construction in August 1944, and design work for EDVAC commenced before ENIAC was fully operational. The design would implement a number of important architectural and logical improvements conceived during the ENIAC's construction and would incorporate a high-speedserial-access memory.[3]Like the ENIAC, the EDVAC was built for theU.S. Army'sBallistics Research Laboratoryat theAberdeen Proving Groundby theUniversity of Pennsylvania'sMoore School of Electrical Engineering.[2]: 626–628 Eckert and Mauchly and the other ENIAC designers were joined byJohn von Neumannin a consulting role; von Neumann summarized and discussed logical design developments in the 1945First Draft of a Report on the EDVAC.[4]
A contract to build the new computer was signed in April 1946 with an initial budget ofUS$100,000. The contract named the device the Electronic Discrete Variable Automatic Calculator. The final cost of EDVAC, however, was similar to the ENIAC's, at just under $500,000.
TheRaytheon Companywas a subcontractor on EDVAC machines.[5]
Technical description
[edit]The EDVAC was a binary serial computer with automatic addition, subtraction, multiplication, programmed division and automatic checking with an ultrasonic serial memory[3]capacity of 1,024 44-bit words, thus giving a memory, in modern terms, of 5.6kilobytes.[6]
Physically, the computer comprised the following components:
- amagnetic tapereader-recorder (Wilkes 1956:36[3]describes this as awire recorder.)
- a control unit with anoscilloscope
- a dispatcher unit to receive instructions from the control and memory and direct them to other units
- a computational unit to perform arithmetic operations on a pair of numbers and send the result to memory after checking on a duplicate unit
- a timer
- a dual memory unit consisting of two sets of 64mercuryacoustic delay lines of eight words capacity on each line
- three temporary delay-line tanks each holding a single word[3]
EDVAC's average addition time was 864 microseconds (about 1,160 operations per second) and its average multiplication time was 2,900 microseconds (about 340 operations per second). Time for an operation depended on memory access time, which varied depending on the memory address and the current point in the serial memory's recirculation cycle.
The computer had 5,937vacuum tubesand 12,000diodes,and consumed 56kWof power. It covered 490 ft² (45.5 m2) of floor space and weighed 17,300 pounds (8.7 short tons; 7.8 t).[7]The full complement of operating personnel was thirty people per eight-hourshift.
EDVAC could also dofloating-point arithmetic.It used 33 bits for themantissaand one bit for its sign. It used 10 bits for the power of 2, including the sign bit.
For executable instructions, the 44-bit word was divided into four 10-bit addresses and four bits to encode the index of an operation. The first two addresses were to the numbers in memory being used in the operation, the third address was for the memory location to store the result, and the fourth address was the location of the next instruction to be executed. Only 12 of the possible 16 instructions were used.
Impact on future computer design
[edit]John Von Neumann's famous EDVAC monograph,First Draft of a Report on the EDVAC,proposed the main enhancement to its design that embodied the principal "stored-program" concept that we now call theVon Neumann architecture.This was the storing of the program in the same memory as the data. The British computersEDSACat Cambridge and theManchester Babywere the first working computers that followed this design, and it has been followed by the great majority of computers made since. Having the program and data in different memories is now called theHarvard architectureto distinguish it.
Installation and operation
[edit]EDVAC was delivered to theBallistics Research Laboratoryin 1949. After a number of problems had been discovered and solved, the computer began operation in 1951 although only on a limited basis.[8][9]
In 1952 (April/May), it was running over 7 hours a day (period from 15 April to 31 May, used for 341 hours).[10]
By 1957, EDVAC was running over 20 hours a day with error-free run time averaging 8 hours. EDVAC received a number of upgrades includingpunch-cardI/O in 1954, extra memory in slowermagnetic drumform in 1955, and afloating-point arithmeticunit in 1958.
EDVAC ran until 1962[8]when it was replaced byBRLESC.
See also
[edit]References
[edit]- ^"The History of Computing at BRL".chimera.roma1.infn.it.RetrievedDecember 3,2021.
- ^abEncyclopedia of computer science.Edwin D. Reilly, Anthony Ralston, David Hemmendinger (4th ed.). Chichester, Eng.: Wiley. 2003.ISBN978-1-84972-160-8.OCLC436846454.
{{cite book}}:CS1 maint: others (link) - ^abcdeWilkes, M. V.(1956).Automatic Digital Computers.New York: John Wiley & Sons. pp. 305 pages. QA76.W5 1956.
- ^"First Draft of a Report on the EDVAC"Archived2004-04-23 at theWayback Machine(PDFformat) by John von Neumann, Contract No.W-670-ORD-4926, between the United States Army Ordnance Department and theUniversity of Pennsylvania.Moore School of Electrical Engineering,University of Pennsylvania, June 30, 1945. The report is also available inStern, Nancy (1981).From ENIAC to UNIVAC: An Appraisal of the Eckert–Mauchly Computers.Digital Press.
- ^"Raytheon Company | Selling the Computer Revolution | Computer History Museum".computerhistory.org.RetrievedApril 20,2022.
- ^BRL report 1961
- ^Weik, Martin H. (December 1955)."EDVAC".ed-thelen.org.A Survey of Domestic Electronic Digital Computing Systems.
- ^abWilliams, Michael R. (1993). "The origins, uses, and fate of the edvac".IEEE Ann. Hist. Comput.15(1): 30, 32–33, 36–37.CiteSeerX10.1.1.705.4726.doi:10.1109/85.194089.S2CID7842904.
- ^"The EDVAC".Digital Computer Newsletter.3(1): 2. April 1951.[dead link]
- ^"6. Aberdeen Proving Ground Computers: The EDVAC".Digital Computer Newsletter.4(3): 4. July 1952.[dead link]
External links
[edit]- Moore School of Electrical Engineering (1949).A Functional Description of the EDVAC: A Report of Development Work under Contract W36-034-ORD-7593 with the Ordnance Department, Department of the Army.Its Research Division Report50-9). Philadelphia: University of Pennsylvania.A complete technical description of EDVAC's original structure and operation in 1949; includes an errata dated 1950. Fully viewable online.
- Oral history interview with J. Presper Eckert,Charles Babbage Institute,University of Minnesota.
- Oral history interview with Carl Chambers,Charles Babbage Institute,University of Minnesota.
- Oral history interview with Irven A. Travis,Charles Babbage Institute,University of Minnesota.
- Oral history interview with S. Reid Warren,Charles Babbage Institute,University of Minnesota.
- Oral history interview with Frances E. Holberton,Charles Babbage Institute,University of Minnesota.
