Von Neumann Architecture - Early Stored-program Computers

Early Stored-program Computers

The date information in the following chronology is difficult to put into proper order. Some dates are for first running a test program, some dates are the first time the computer was demonstrated or completed, and some dates are for the first delivery or installation.

• The IBM SSEC had the ability to treat instructions as data, and was publicly demonstrated on January 27, 1948. This ability was claimed in a US patent. However it was partially electromechanical, not fully electronic. In practice, instructions were read from paper tape due to its limited memory.
• The Manchester SSEM (the Baby) was the first fully electronic computer to run a stored program. It ran a factoring program for 52 minutes on June 21, 1948, after running a simple division program and a program to show that two numbers were relatively prime.
• The ENIAC was modified to run as a primitive read-only stored-program computer (using the Function Tables for program ROM) and was demonstrated as such on September 16, 1948, running a program by Adele Goldstine for von Neumann.
• The BINAC ran some test programs in February, March, and April 1949, although was not completed until September 1949.
• The Manchester Mark 1 developed from the SSEM project. An intermediate version of the Mark 1 was available to run programs in April 1949, but was not completed until October 1949.
• The EDSAC ran its first program on May 6, 1949.
• The EDVAC was delivered in August 1949, but it had problems that kept it from being put into regular operation until 1951.
• The CSIR Mk I ran its first program in November 1949.
• The SEAC was demonstrated in April 1950.
• The Pilot ACE ran its first program on May 10, 1950 and was demonstrated in December 1950.
• The SWAC was completed in July 1950.
• The Whirlwind was completed in December 1950 and was in actual use in April 1951.
• The first ERA Atlas (later the commercial ERA 1101/UNIVAC 1101) was installed in December 1950.