Encyclopedia > Manchester Mark I

  Article Content

Manchester Mark I

The Manchester Mark I was one of the earliest electronic computers, built at the University of Manchester in 1949.

In its final specification (October 1949) it stored data in one 40-bit number (the accumulator) or two 20-bit instruction registers, and had two 20-bit address modifier registers. It could perform serial 40-bit arithmetic, with hardware add, subtract and multiply and logical instructions. It used single-address format order code with thirty function codes. Standard instruction time was 1.8 milliseconds, but multiplication was much slower.

For memory the Mark I used two Williams tubes, each storing 64 rows of 40 points, for a total of 128 words. 64 words was considered to be a single "page", so the system stored 4 pages. In addition to the tubes were a magnetic drums, which could store 32 pages each. Instructions were loaded into the machine by using paper tape.

The Mark I was developed from the Small-Scale Experimental Machine[?] (SSEM), nicknamed Baby, developed by Frederic C. Williams[?] and Tom Kilburn[?], which ran its first successful program on June 21, 1948. The Manchester Mark I led to the Ferranti Mark I[?], the first commercially available computer.

See: http://www.computer50.org/mark1/MM1

All Wikipedia text is available under the terms of the GNU Free Documentation License

  Search Encyclopedia

Search over one million articles, find something about almost anything!
  Featured Article

...     Contents Autocracy Autocracy is a form of government which resides in the absolute power of a single individual. The term can b ...

This page was created in 24.1 ms