|Columbia University Computing History|
As with all IBM punch-card equipment except the key punch and sorter, a control panel is wired to specify the details of operation: what card columns to read and what to do with them, how to format the report. Although the 407 is really just a big adding machine, creative use could be made of the control program; for example, as described by Roger L. Boyell in Programmed Multiplication on the IBM 407, Journal of the ACM, Volume 4, Number 4, October, 1957, pp.442-449. In 1955, the 407 was adapted to act as an input/output device for the IBM 650 computer, and would later perform similar roles for other IBM calculators (such as the CPC-II) and computers (7090); reportedly, a 407 even served as the "system clock" for Columbia's 7094.
Fred Stone points out, "The speed was a function of what you were doing. If you were just posting, reading a card and printing, the maximum speed was a whopping 150 cards per minute. There was a model E8, that was offered with the IBM 1620 to be used as an offline printer. That was a stripped unit that would skip every third cycle and was crippled to run at 100 cards per minute. With the purchase of 2 relays (if I remember corectly) and adding a jumper you could defeat the crippling circuitry and get it back to 150 cpm." Mike McCants, a 1620 programmer at Rice University in the 1960s, comments (November 2002), "As one who helped perform such a modification in 1963, my memory is a little different. There were already two extra relays in this model E8. The purpose of the two extra relays was to count 1, count 2, and then cause the machine to pause. Thus the 150 cards/minute printer was slowed to 100 cards/minute. My memory is that it took us only an hour or so to read the documentation in the back of the cabinet and figure out how to bypass the two relays and restore the 407 to its rated speed of 150 cards/minute. This happened about one hour after the SE finished installing the machine :-)"
|IBM 407 Reference Manual 1950|
|German||Deutsch||2019/05/16||Sarah Richards||Essay Writing Services|
Last update: 31 May 2019