EDSAC

Squares of 0 to 99

At the University of Cambridge Mathematical Laboratory on 6 May 1949, EDSAC operated successfully for the first time and printed a table of the squares of the integers from 0 through 99.

The surviving project log records that the program took 2 minutes 35 seconds and that four storage tanks of the first memory battery were operating.

The machine had been designed and built under Maurice Wilkes's leadership as a practical stored-program computer intended to supply computation to university researchers.

The primes came later, and buggy

A correct table of squares did not mean every program worked. A prime-number program failed on 7 May and succeeded after correction on 9 May.

The chief engineer, William S. Renwick, wrote the surviving first section of the log. David Wheeler, a research student, transcribed it and worked on EDSAC's initial orders, closed subroutines and prime-number routines.

Who wrote it, and what "first" means here

The original 6 May program is lost and the contemporary log names no author. Beatrice Worsley, a visiting Canadian computing researcher, was present and helped prepare EDSAC for the run, but the available sources do not securely establish that she alone wrote it.

EDSAC was also not the first machine ever to execute a stored program — the Manchester Baby did that in 1948. Cambridge's narrower claim is that EDSAC was the first complete, fully operational electronic stored-program computer to provide a regular service, and sources differ over how to compare it with the Manchester Mark 1, still under development in 1949.