SEAC (computer)
SEAC , which stands for English S tandards E astern A utomatic C omputer , was in 1950 one of the first digital computer at the National Bureau of Standards (NBS, now NIST). SEAC was planned by the NBS as a transition computer system to the not yet available successor computer DYSEAC , and characterized by a comparatively simple and quick structure of the computer system.
The computer was used for scientific calculation purposes, for example for dimensioning the first proton synchrotron , the beginnings in the field of image processing and the calculation of the wave function of the helium atom. SEAC was developed by a team led by Samuel N. Alexander , put into operation in April 1950 and taken into regular operation in May 1950. The computer system was in operation until 1960. In 1964, parts of SEAC were given to the Smithsonian Institution as museum pieces.
construction
SEAC was a tube computer consisting initially of 747 electron tubes , later expanded to approx. 1500 electron tubes. Its architecture was based on the previous model, the Electronic Discrete Variable Automatic Computer (EDVAC), and in contrast to this, around 10,500 of the then new types of germanium diodes were used in the SEAC . The computer thus represents the technological transition to semiconductor technology in the field of computer technology. Later the number of germanium diodes was increased to approx. 16,000. The diodes were primarily used to implement logical links such as the AND link , the electron tubes were used for signal amplification and the construction of memory elements in the form of the Williams tube.
The computer also consisted of 64 acoustic delay lines which were used for short-term data storage of 512 bits. The word length was 45 bits. In the initial configuration, the central processing unit could execute 11 different commands, including the fixed-point calculations of addition, subtraction, multiplication and division, as well as comparison commands and instructions for input and output. In later expansion stages the number of commands was increased to 16.
At a clock frequency of just under 1 MHz , SEAC was able to carry out a fixed point addition in 864 µs , a multiplication took almost 3 ms.
Web links
Individual evidence
- ↑ a b 1955 BRL report, SEAC. Retrieved August 15, 2016 .
- ^ Russell A. Kirsch: Standards Electronic Automatic Computer (SEAC). (No longer available online.) Archived from the original on September 20, 2016 ; accessed on August 15, 2016 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Obituary: Samuel Alexander, NBS Senior Research Fellow Archived from the original on September 23, 2013. Info: The archive link was automatically inserted and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: Physics Today . 21, No. 4, April 1968, p. 131. doi : 10.1063 / 1.3034910 . Retrieved August 15, 2016.
