Investigations for a Josephson Computer Main Memory with Single-Flux-Quantum Cells

The paper first summarizes requirements for a main memory with Josephson junctions and reviews the work carried out on an experimental main memory model containing an array of single-flux-quantum cells, line drivers, and address decoders with a total of nearly 4500 Josephson junctions. In the second part, theoretical and experimental investigations on the y drive system, including sense circuit, are presented. The investigations deal with both the read and write phases. Finally, the on-chip logic circuits and the address decoders are discussed, and the experimental results presented. Drivers and decoders based on the principle of current steering in superconducting loops are intended to be used on a fully populated main-memory chip.