Plated wire 200-ns main memory

A 4-K-word 50-bit-per-word plated wire main memory was constructed and tested at a 200-ns cycle time. 32 matrix planes were constructed of the woven wire type (each plane contained 128 words and was stacked into 2 blocks for a total capacity of 4 K words). Special design features for high-speed operations are 1) memory stack construction with memory planes which are serially connected with grounded conductors, 2) balanced word line driving using transmission-line-type transformers, 3) bridge configuration of the digit-sense system, and 4) digit driving scheme using nonreturn-to-zero current. Operating margins of the system were tested with an account being taken of the effect of magnetic domain wall creeping for more than 106 disturb pulses.