EDSAC
Webpages concerning "EDSAC"
|
The contents has been generating using technology developed by scientec.
Wikipedia-Article "EDSAC"
EDSAC (Electronic Delay Storage Automatic Calculator) was an early British computer. The machine, having been inspired by John von Neumann's seminal EDVAC report, was constructed by Maurice Wilkes and his team at the University of Cambridge Mathematical Laboratory in England.
EDSAC was the world's first practical stored program electronic computer, although not the first stored program computer (that honor goes to the Small-Scale Experimental Machine).
The project was supported by J. Lyons & Co. Ltd., a British firm, who were rewarded with the first commercially applied computer, LEO I, based on the EDSAC design. EDSAC ran its first programs on May 6, 1949, calculating a table of squares[1] and a list of prime numbers.
Contents |
Technical overview
Physical components
As soon as EDSAC was constructed, it immediately began serving the University's research needs. None of its components were experimental. It used mercury delay lines for memory, and derated vacuum tubes for logic.
Initially registers were limited to an accumulator and a multiplier register. In 1953, David Wheeler, returning from a stay at the University of Illinois, designed an index register as an extension to the original EDSAC hardware.
Memory and instructions
The EDSAC's memory consisted of 1024 locations. Each contained 18 bits, but the first bit was unreliable, so only 17 bits were used. An instruction consisted of a five-bit instruction code (designed to be represented by a mnemonic letter, so that the Add instruction, for example, used the bit pattern for the letter A), eleven bits for a memory address (although with 1024 words, only 10 bits were needed), and one bit (for certain instruction) to control whether the instruction operated on a number contained in one word or two.
System software
The loader programs located in the lower words of memory at startup were actually primitive assemblers taking advantage of the mnemonic design described above. The second version of the loader program (known as Initial Orders 2) was sophisticated enough to handle relocatable addresses, which allowed for the creation of a subroutine library.
Applications of EDSAC
- In 1951, Miller and Wheeler used the machine to discover a 79-digit prime—the largest known at the time.
- In 1952 A.S. Douglas developed OXO, a version of noughts and crosses (tic-tac-toe) for the EDSAC, with graphical output to a cathode ray tube. This may well have been the world's first computer/video game.
- In the 1960s EDSAC was used to gather numerical evidence about solutions to elliptic curves, which led to the Birch and Swinnerton-Dyer conjecture.
Further developments
EDSAC's successor, EDSAC 2, was commissioned in 1958. In 1961 an EDSAC 2 version of Autocode, an Algol-like high-level programming language for scientists and engineers, was developed by D. F. Hartley.
In the mid-60s, a successor to the EDSAC 2 was planned, but the move was instead made to the Titan, a prototype Atlas 2—the latter having been developed from the Atlas Computer of the University of Manchester, Ferranti, and Plessey.
Notes
- ^ To be precise, EDSAC's first program printed a list of the squares of the integers from 0 to 99 inclusive.
External links
- An EDSAC simulator – Developed by Martin Campbell-Kelly, Department of Computer Science, University of Warwick , England
- 50th Anniversary of EDSAC – Dedicated website at the University of Cambridge Computer Laboratory