IBM 604
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The IBM 604 was a plug-board programmable Electronic Calculating Punch introduced in 1948, and was a machine on which considerable expectations for the future of IBM were pinned and in which a corresponding amount of planning talent was invested.
Most of the circuitry was based on modifications of circuit designs used in the earlier 603 Electronic Multiplier and was packaged in small one-tube-replaceable standardized modules. The calculation unit contained 1,400 tubes. Clock speed was increased from the 603's rate of 35kHz to 50kHz. The 604 performed fixed point addition, subtraction, multiplication and division using BCD arithmetic.
Initial versions supported 40 program steps, but this was soon expanded to 60. Processing was still locked to the reader/punch cycle time, thus program execution had to complete within the time between a punched card leaving the read station and entering the punch station.
In 1949 a modified version of the 604, the 605, connected to an accounting machine, the 418, was introduced as the Card Programmed Electronic Calculator. This machine read its program steps from punch cards instead of a plug-board.
See also: List of IBM products.
External link
- IBM-604 Electronic Calculating Punch (http://ed-thelen.org/comp-hist/IBM-604.html)