Self-Diagnosis and Self-Repair in Memory: An Integrated System Approach

This paper presents an integrated approach to the design of an ultrareliable memory system using a variety of coding and modularization techniques on each of the memory subsystem elements. The overall objective is to provide a properly operating memory system in spite of any single indigenous fault (regardless of the number of failures which might ensue). In other words, the system has the capability automatically to: (1) detect single faults and multiple failures, (2) mask failures to prevent malfunctions, without interrupting service, (3) isolate the fault to a replaceable module, and (4) reconfigure the faulty unit out of the system. The storage medium and retrieval circuits are checked and corrected by coding techniques. Some redundancy is used on the subunits, but the total redundancy is less than 20% of the system cost, and diagnostic software is eliminated.