Evolution of the Computer Industry

ENIAC – the first large scale electronic digital computer

In 1946, after spending about $400,000.00, Mauchly and Eckert completed the ENIAC (Electronic Numerical Integrator and Computer), the first-large scale electronic digital computer ever built. The ENIAC contained 18,000 vacuum tubes and could multiply two numbers in about 3 milliseconds(3/1000th of a second).

The ENIAC was programmed by connecting various wires between units of the computer and setting up to 6,000 switches in such a way that the program would be executed.

The co-investors of the ENIAC, John Presper Eckert and John W. Mauchly.

The ENIAC weighed 30 tons, contained 18.000 vacuum tubes, and occupied a space 30 by 50 feet.

EDVAC - Electronic Discrete Variable Automatic Computer

EDVAC (Electronic Discrete Variable Automatic Computer) was one of the earliest electronic computers. Unlike its predecessor the ENIAC, it was binary rather than decimal, and was a stored program machine.

The EDVAC was a binary serial computer with automatic addition, subtraction, multiplication, programmed division and automatic checking with an ultrasonic serial memory[1] capacity of 1,000 44-bit words (later set to 1,024 words, thus giving a memory, in modern terms, of 5.5 kilobytes).

Project origin and plan

• ENIAC inventors John Mauchly and J. Presper Eckert proposed the EDVAC's construction in August 1944, and design work for the EDVAC commenced before the 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 speed serial access memory.[1] Like the ENIAC, the EDVAC was built for the U.S. Army's Ballistics Research Laboratory at the Aberdeen Proving Ground by the University of Pennsylvania's Moore School of Electrical Engineering. Eckert and Mauchly and the other ENIAC designers were joined by John von Neumann in a consulting role; von Neumann summarized and elaborated upon logical design developments in his 1945 First Draft of a Report on the EDVAC.[2]

• A contract to build the new computer was signed in April 1946 with an initial budget of US$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.

Technical description

• Physically, the computer comprised the following components:

• a magnetic tape reader-recorder (Wilkes 1956:36[1] describes this as a wire recorder.)

• a control unit with an oscilloscope • 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 at a time and send the result to memory after checking on a duplicate unit

• a timer • a dual memory unit consisting of two sets of 64 mercury

acoustic delay lines of eight words capacity on each line • three temporary tanks each holding a single word[1]

• An oscilloscope (abbreviated sometimes as scope or O-scope) is a type of electronic test instrument that allows signal voltages to be viewed, usually as a two-dimensional graph of one or more electrical potential differences (vertical(Y) axis) plotted as a function

of time or of some other voltage (horizontal(x) axis).

Installation and operation• EDVAC was delivered to the Ballistics Research Laboratory in

August 1949. After a number of problems had been discovered and solved, the computer began operation in 1951 although only on a limited basis. Its completion was delayed because of a dispute over patent rights between Eckert and Mauchly and the University of Pennsylvania, resulting in Eckert and Mauchly's resignation and departure to form the Eckert-Mauchly Computer Corporation and taking most of the senior engineers with them.

• By 1960 EDVAC was running over 20 hours a day with error-free run time averaging eight hours. EDVAC received a number of upgrades including punch-card I/O in 1953, extra memory in slower magnetic drum form in 1954, and a floating point arithmetic unit in 1958.

• EDVAC ran until 1961 when it was replaced by BRLESC. During its operational life it proved to be reliable and productive for its time.

EDSAC – Electronic Delay Storage Automatic Calculator

In 1946, von Neumann and others conducted classes at the University of Pennsylvania on computer design and the concept of stored program computers. One of the students was Maurice V. Wilkes from Cambridge University, England. Upon his return to England, Wilkes and his colleagues at Cambridge began work on the EDSAC.

Completed in May 1949, it was the first computer which operated using the stored program concept.

(The EDVAC, developed by von Neumann, was not to work until 1951)

UNIVAC 1