IBMs Selective Sequence Electronic Calculator was built

IBMs Selective Sequence Electronic Calculator was built

IBM's Selective Sequence Electronic Calculator (SSEC), was built at IBM's Endicott facility under the direction of Columbia Professor Wallace Eckert and his Watson Scientific Computing Laboratory staff.

Designed, built, and placed in operation in only two years, the SSEC contained 21,400 relays and 12,500 vacuum tubes. It could operate indefinitely under control of its modifiable program. On the average, it performed 14-by-14 decimal multiplication in one-fiftieth of a second, division in one-thirtieth of a second, and addition or subtraction on ninteen-digit numbers in one-thirty-five-hundredth of second... For more than four years, the SSEC fulfilled the wish Watson had expressed at its dedication: that it would serve humanity by solving important problems of science. It enabled Wallace Eckert to publish a lunar ephemeris ... of greater accuracy than previously available... the source of data used in man's first landing on the moon" 
"For each position of the moon, the operations required for calculating and checking results totaled 11,000 additions and subtractions, 9,000 multiplications, and 2,000 table look-ups. Each equation to be solved required the evaluation of about 1,600 terms altogether an impressive amount of arithmetic which the SSEC could polish off in seven minutes for the benefit of the spectators"

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IBMs Selective Sequence Electronic Calculator  was built

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