The ORDVAC (Ordnance Discrete Variable Automatic Computer), is an early computer built by the University of Illinois for the Ballistic Research Laboratory at Aberdeen Proving Ground.[1] It was a successor to the ENIAC (along with EDVAC built earlier). It was based on the IAS architecture developed by John von Neumann, which came to be known as the von Neumann architecture. The ORDVAC was the first computer to have a compiler. ORDVAC passed its acceptance tests on March 6, 1952, at Aberdeen Proving Ground in Maryland.[2][3]: IV [4] Its purpose was to perform ballistic trajectory calculations for the US Military. In 1992, the Ballistic Research Laboratory became a part of the U.S. Army Research Laboratory.
Unlike the other computers of its era, the ORDVAC and ILLIAC I were twins and could exchange programs with each other. The later SILLIAC computer was a copy of the ORDVAC/ILLIAC series. J. P. Nash of the University of Illinois was a developer of both the ORDVAC and of the university's own identical copy, the ILLIAC, which was later renamed the ILLIAC I. Abe Taub, Sylvian Ray, and Donald B. Gillies[5] assisted in the checkout of ORDVAC at Aberdeen Proving Ground. After ORDVAC was moved to Aberdeen, it was used remotely by telephone by the University of Illinois for up to eight hours per night. It was one of the first computers to be used remotely and probably the first to routinely be used remotely.
The ORDVAC used 2178 vacuum tubes. Its addition time was 72 microseconds and the multiplication time was 732 microseconds. Its main memory consisted of 1024 words of 40 bits each, stored using Williams tubes. It was a rare asynchronous machine, meaning that there was no central clock regulating the timing of the instructions. One instruction started executing when the previous one finished.
Among the ORDVAC programmers were Martin Davis[6] and Elsie Shutt.
ORDVAC and its successor at Aberdeen Proving Ground, BRLESC, used their own unique notation for hexadecimal numbers. Instead of the sequence A B C D E F universally used today, the digits ten to fifteen were represented by the letters K S N J F L (King Sized Numbers Just For Laughs), corresponding to the teleprinter characters on five-track paper tape. The manual that was used by the military in 1958 used the name sexadecimal for the base 16 number system.
^"The History of Computing at BRL". chimera.roma1.infn.it. Retrieved 2021-12-03.
^Metropolis, Nicholas (2014-06-28). History of Computing in the Twentieth Century. Elsevier. pp. 359–360. ISBN 9781483296685.
^Cite error: The named reference mv1 was invoked but never defined (see the help page).
^"The ORDVAC". Digital Computer Newsletter. 4 (3). In use from 9 March: 4. 1952.{{cite journal}}: CS1 maint: others (link)[dead link]
^"About Abraham Haskel Taub". Archived from the original on 2017-03-14. Retrieved 2017-03-14.
^Jackson, Allyn (2008-05-01). "Interview with Martin Davis" (PDF). American Mathematical Society. Retrieved 2021-05-20.
The ORDVAC (Ordnance Discrete Variable Automatic Computer), is an early computer built by the University of Illinois for the Ballistic Research Laboratory...
role in the computer designs. ORDVAC was the first of two computers built under contract at the University of Illinois. ORDVAC was completed the spring of...
1952. It was the second of two identical computers, the first of which was ORDVAC, also built at the University of Illinois. These two machines were the first...
Moore School of Electrical Engineering, Pennsylvania.: 626–628 Along with ORDVAC, it was a successor to the ENIAC. Unlike ENIAC, it was binary rather than...
and was designed to take over the computational workload of EDVAC and ORDVAC, which themselves were successors of ENIAC. It began operation in 1962....
construct their computers. Among these various computers, only ILLIAC and ORDVAC had compatible instruction sets. ARC2 (Birkbeck, University of London) officially...
and the U.S. Army to create the ORDVAC and ILLIAC I computers under the direction of physicist Ralph Meagher. The ORDVAC and ILLIAC computers the two earliest...
were developed in early 1950s as part of bigger asynchronous systems (e.g. ORDVAC). Asynchronous circuits and theory surrounding is a part of several steps...
instruction set computers. Among these various computers, only ILLIAC and ORDVAC had compatible instruction sets. Manchester Baby (University of Manchester...
type used in ILLIAC III Printed circuits of the type used in ILLIAC III ORDVAC ILLIAC I ILLIAC II ILLIAC IV "Prof. John P. Hayes retires after half a century...
the lowercase letters u, v, w, x, y and z for the values 10 to 15. The ORDVAC and ILLIAC I (1952) computers (and some derived designs, e.g. BRLESC) used...
October 2, 1955, when it was retired in favor of the more efficient EDVAC and ORDVAC computers. A few months after ENIAC's unveiling in the summer of 1946, as...
finally crashing in a wooded area in northeastern Pennsylvania. ENIAC ORDVAC BRLESC Aberdeen scandal (1996) United States Army Research Laboratory Ballistic...
discusses the EDSAC project, the influence of EDSAC on the ILLIAC, the ORDVAC, and the IBM 701 computers, as well as visits to Cambridge by Douglas Hartree...
four early computers, 1962. From left to right: ENIAC board, EDVAC board, ORDVAC board, and BRLESC-I board, showing the trend toward miniaturization....
built by the University of Sydney, Australia, was based on the ILLIAC and ORDVAC computers developed at the University of Illinois. Like other early computers...
user-oriented programming methods, and the influence of EDSAC on the ILLIAC, the ORDVAC, and the IBM 701. Wheeler also notes visits by Douglas Hartree, Nelson Blackman...
Engineering library, although it would not be packaged as a single report. ORDVAC ILLIAC I ILLIAC III ILLIAC IV Brearley, H.C. (1965), "ILLIAC II – A short...
had already acquired the Ordnance Discrete Variable Automatic Computer (ORDVAC), which the lab had commissioned the University of Illinois to build. As...
user-oriented programming methods, and the influence of EDSAC on the ILLIAC, the ORDVAC, and the IBM 701. Biographical Librarian, St. John's College, Cambridge...
to teach English in France. Shutt learned to program on ENIAC successor ORDVAC (Ordnance Discrete Variable Automatic Computer) under Dick Clippinger during...
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