Selective Sequence Electronic Calculator
The Selective Sequence Electronic Calculator ( SSEC ) was built in 1946/47 under the direction of Columbia Professor Wallace John Eckert of the Watson Scientific Computing Laboratory and was a hybrid computer that consisted of both 12,500 tubes and 21,400 mechanical relays . It was located in the IBM headquarters in Manhattan , where it covered the walls of an 18 × 9 meter room, according to other sources an 18, 12 and 24 meter long wall. He started work on January 27, 1948.
SSEC performed an important task: it calculated the positions of the moon that would make the Apollo landings possible. Each position required 11,000 additions and subtractions, 9,000 multiplications, and 2,000 searches to a database. In turn, 1,600 relationships had to be included in each calculation. This process took seven minutes, to the amazement of the audience.
The single piece was dismantled again in July 1952 to make room for the new Defense Calculator ( IBM 701 ).
From a technical point of view (Eckert was an astronomer), Frank E. Hamilton was particularly involved at IBM .
Web links
- The IBM IBM SSEC (English)