Mark I
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History of Computers: During the 1940s the MARK series of computers were developed at Harvard University. The first of these computers, the Mark I, was put into operation in 1944 and was used until 1959 at Harvard. It was about 55 ft. long and 8 ft. high. The device contained almost 760,000 parts and about 500 miles of wire. The
Harvard Mark I computer could carry out five operations, addition, subtraction, multiplication, division and reference to previous
results; moreover, it had special built-in programs, or subroutines, to
handle logarithms and trigonometric functions. It stored and counted
numbers mechanically using 3000 decimal storage wheels, 1400 rotary dial
switches, and 500 miles of wire but transmitted and read the data
electrically. It
was programmed by punch cards, weighed 5 tons, and could do a
multiplication operation in about 6 seconds. Like the earliest
mechanical computers, the data to be used in a Mark computer was stored
in a separate part of the machine from the instructions (or program)
that would operate on the data. Also, the instructions were stored in a
different format than the data. The
Mark I was originally controlled from pre-punched paper tape without
provision for reversal, so that automatic "transfer of
control" instructions could not be programmed. Output was by card
punch and electric typewriter. Because of the electromagnetic relays,
the machine was classified as a relay computer. It was fully automatic
and could complete long computations without human intervention. References: |
