Size and speed capabilities of DRO film memories

The memory cycle time and size capabilities of destructive read-out (DRO) film memories are examined on the following bases: an assumed memory-element geometry which can be easily fabricated, a memory organization which minimizes propagation delays per element, the gain bandwidth product of drive and amplifying devices, the switching speed of magnetic films (including the effects of eddy currents), the recovery time from digit-line transients, and the limitations of demagnetizing fields. The results show that, depending on the size of the memory and the capabilities of the drive and amplifying devices, the memory speed can be limited chiefly by propagation delay, electronic delay, or the magnetic-film switching speed. The analysis indicates that memories with 10⁶ bits of storage and cycle times less than 100 nsec (nanoseconds) could be achieved with existing devices.