As a result of a trip to the U.S.A. in June 1946, Dr F.C. (Freddie) Williams started active investigation at TRE into the storage of both analog and digital information on a Cathode Ray Tube. Storage of analog information could help solve the problem of static objects cluttering the dynamic picture on a radar screen (because). Storage of digital information could solve the problem holding up the development of computers worldwide, i.e. lack of a storage mechanism that would work at electronic speeds. By November 1946 he was able to store a single bit (with the “anticipation” method), based around a standard radar CRT, and filed a provisional patent for the mechanism in December 1946.
The general principle behind the storage of binary information was to plant charge in one of two different ways at an array of spots on a CRT using standard techniques. The type of charge at any spot, representing a 0 or 1, could be sensed by a metal pick-up plate on the outside of the CRT screen, thus “reading” the “value” of the spot. However, the charge dissipated very quickly, so values were preserved indefinitely by continuously reading their value and resetting the charge as appropriate to the value.