The design of a 4096-word one-microsecond magnetic film store

The store is made up of a large number of aluminium plates coated with thin magnetic film. It is word-organized and bi-directional digit currents are used for writing. The word and digit lines consist of conductors pressed against the plates and these define the storage positions on the continuous areas of film. Advantage is taken of the low impedance of the film to provide the word selection at low cost. A store-size ferrite core serves as the selection device for each word and a matrix of diodes directs the drive currents the chosen lines of cores. A single set of digit conductors are used for both sensing and write back and these serve all the 4096 words of the store. The digit current disturbance is minimized by a special balancing arrangement.