The Selective Sequence electronics Calculator (SSEC) was built for 1946/47 under the line of Columbia professor Wallace Eckert by the Watson Scientific Computing Laboratory and was a hybrid computer, which consisted both of 12.500 tubes and of 21.400 mechanical relays. It was located in IBM headquarters in Manhattan and took there with a size of 60 times 40 foot the place half football field. On 27 January 1948 it took up the work.

An important task fulfilled SSEC: It computed moon positions, with which the Apollo landings were made possible. Each position required 11,000 additions and subtractions, 9000 multiplications and 2000 retrieval queries to a data base. Into each computation again 1600 relations had to be included. This procedure took - to the astonishment of the spectators - seven minutes.

The unique piece was again dismantled in July 1952, in order to make place for the new Defense Calculator (IBM 701).

Related links

• The IBM Selective Sequence electronics Calculator

Articles in category "Selective Sequence electronics Calculator"

We found here 3 articles.

Related Websites

We found here 5 related websites.

• IBM Archives: IBM Mainframes
  In 1952, IBM announced its first fully electronic data processing system, the IBM 701 . The four years between the Selective Sequence Electronic Calculator ...


• IBM Archives: Installation of the first 701
  The 701 has at least 25 times the over-all speed but is less than one-quarter the size of IBM's Selective Sequence Electronic Calculator, ...


• IBM Archives: Selective Sequence Electronic Calculator (SSEC)
  IBM Archives: Exhibits: A notable first - IBM 701: Selective Sequence Electronic Calculator (SSEC)


• IBM SSEC
  IBM's Selective Sequence Electronic Calculator (SSEC), built at IBM's Endicott facility under the direction of Columbia Professor Wallace Eckert and his ...


• Way Back Computing
  The new, all electronic device was called the Selective Sequence Electronic Calculator (SSEC) and was completed in 1948. It was put on public display at 590 ...