 On 21 June 1948, after months of patient work constructing and testing the Baby piece by piece, coping with the unreliable electronic components of the day, the machine finally ran a routine written by Kilburn (they didn't use the word "program" then) to find the highest proper factor of a number.In Tootill's words "And we saw the thing had done a computation".A day or two later, the Baby ran successfully for 52 minutes to find the highest proper factor of 218, which required c. 3.5m arithmetic operations.