IBM 701

The Speed Demon

IBM’s first commercially available scientific computer was 701, the first one of the IBM 700 series. 701 developed in record time of two years was introduced to public in 1953. In 1952, 701 was considered to be the speed demon. IBM 701 earlier named as the Defense Calculator was mainly funded by pentagon. The impetus for defense calculator came from the Korean War that led to the need for equipment capable of operating at higher speed and accuracy. Despite the name Defense Calculator was stored-program computer.

The initial nomenclature referred to 701 as ‘machines’ since it comprised of 11 connected units. Later usage adopted of the singular form.

Taming the speed demon

Speed of 701 is not that impressive as compared to modern computers but 701 in its own time was way ahead in the race. The 701 could perform more than 16,000 addition or subtraction operations a second, read 12,500 digits a second from tape, print 180 letters or numbers a second, and output 400 digits a second from punched-cards. At that point IBM was facing a problem – how to keep the machine busy. This lead to hardware and software considered being the yin and yang of computing. The bottleneck was the programming. Only a small people had the knowledge of programming. Programming at that time revolved around punched cards. Programs would be written on paper and then punched onto cards. Next the cards were placed into card reading machine. The card reader then fed the data and programming instructions, which were then interpreted by the computer and executed. Any bugs encountered would then be worked upon and new program was written and the whole procedure was repeated till error free program was obtained. It was time for a “better way” of programming. And that better way was FORTRAN