ORDVAC
Encyclopedia
The ORDVAC or Ordnance Discrete Variable Automatic Computer, an early computer
built by the University of Illinois
for the Ballistics Research Laboratory at Aberdeen Proving Ground
, 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 became operational in the Spring of 1951 at Aberdeen Proving Ground in Maryland. Its purpose was to perform ballistic trajectory calculations for the US Military.
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. Donald B. Gillies
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 tube
s. Its addition time was 72 microseconds and the multiplication time was 732 microseconds. Its main memory consisted of 1024 words of 40 bit
s each, stored using Williams tube
s. 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.
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 5-track paper tape
.
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...
built by the University of Illinois
University of Illinois at Urbana-Champaign
The University of Illinois at Urbana–Champaign is a large public research-intensive university in the state of Illinois, United States. It is the flagship campus of the University of Illinois system...
for the Ballistics Research Laboratory at Aberdeen Proving Ground
Aberdeen Proving Ground
Aberdeen Proving Ground is a United States Army facility located near Aberdeen, Maryland, . Part of the facility is a census-designated place , which had a population of 3,116 at the 2000 census.- History :...
, was based on the IAS
IAS machine
The IAS machine was the first electronic computer built by the Institute for Advanced Study , in Princeton, New Jersey, USA. It is sometimes called the von Neuman machine, since the paper describing its design was edited by John von Neumann, a mathematics professor at both Princeton University...
architecture developed 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,...
, which came to be known as the von Neumann architecture
Von Neumann architecture
The term Von Neumann architecture, aka the Von Neumann model, derives from a computer architecture proposal by the mathematician and early computer scientist John von Neumann and others, dated June 30, 1945, entitled First Draft of a Report on the EDVAC...
. The ORDVAC was the first computer to have a compiler
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...
. ORDVAC became operational in the Spring of 1951 at Aberdeen Proving Ground in Maryland. Its purpose was to perform ballistic trajectory calculations for the US Military.
Unlike the other computers of its era, the ORDVAC and ILLIAC I
ILLIAC I
The ILLIAC I , a pioneering computer built in 1952 by the University of Illinois, was the first computer built and owned entirely by a US educational institution, Manchester University UK having built Manchester Mark 1 in 1948.ILLIAC I was based on the Institute for Advanced Study Von Neumann...
were twins and could exchange programs with each other. The later SILLIAC
SILLIAC
The SILLIAC , an early computer built by the University of Sydney, Australia, was based on the ILLIAC and ORDVAC computers developed at the University of Illinois, which in turn were based on the IAS architecture developed by John von Neumann.SILLIAC had its genesis in...
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
ILLIAC I
The ILLIAC I , a pioneering computer built in 1952 by the University of Illinois, was the first computer built and owned entirely by a US educational institution, Manchester University UK having built Manchester Mark 1 in 1948.ILLIAC I was based on the Institute for Advanced Study Von Neumann...
, which was later renamed the ILLIAC I. Donald B. Gillies
Donald B. Gillies
Donald Bruce Gillies was a Canadian mathematician and computer scientist, known for his work in game theory, computer design, and minicomputer programming environments.- Education :...
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 tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
s. Its addition time was 72 microseconds and the multiplication time was 732 microseconds. Its main memory consisted of 1024 words of 40 bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...
s each, stored using Williams tube
Williams tube
The Williams tube or the Williams-Kilburn tube , developed in about 1946 or 1947, was a cathode ray tube used to electronically store binary data....
s. It was a rare asynchronous
Asynchronous circuit
An asynchronous circuit is a circuit in which the parts are largely autonomous. They are not governed by a clock circuit or global clock signal, but instead need only wait for the signals that indicate completion of instructions and operations. These signals are specified by simple data transfer...
machine, meaning that there was no central clock regulating the timing of the instructions. One instruction started executing when the previous one finished.
ORDVAC and its successor at Aberdeen Proving Ground, BRLESC
BRLESC
The BRLESC I was a first-generation electronic computer built by the United States Army's Ballistics Research Laboratory at Aberdeen Proving Ground with assistance from the National Institute of Standards and Technology , and was designed to take over the computational workload...
, used their own unique notation for hexadecimal
Hexadecimal
In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...
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
Teleprinter
A teleprinter is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the...
characters on 5-track paper tape
Punched tape
Punched tape or paper tape is an obsolete form of data storage, consisting of a long strip of paper in which holes are punched to store data...
.