A computer fixed store using light pulses for read-out

The store has an access time of 20 ns and can be interrogated every 100 ns. Information is stored on a punched card, or photographic matrix, and interrogation is by means of light pulses transmitted along optical systems composed of bunches of fine transparent optical fibres. Calculations show that a particular case is capable of storing 108bits but practical considerations reduce this to 2.5 × 106bits in a storage area of 40 × 40 cm.