An interleaved-digit magnetic-drum store for a transistor digital computer

The magnetic-drum store for a small transistor digital computer operating at 58kc/s is described. The logical design of the computer requires the interleaving of the digits of the words¿an arrangement which makes many words on the drum available concurrently and therefore permits economical 3-address operation. The working store has a capacity of 426 words, including a regenerative loop which is necessary for temporary storage, since not all the words are available concurrently. The proposed main store, which will be relay selected, has a capacity of 16384 words. Circuits are described for writing and reading the interleaved words on to and from the drum and for producing the timing pulses for the whole computer.