The implementation and application of micro rollback in fault-tolerant VLSI systems

The authors present a technique, called micro rollback, which allows most of the performance penalty for concurrent error detection to be eliminated. Detection is performed in parallel with the transmission of information between modules, thus removing the delay for detection from the critical path. Erroneous information may thus reach its destination module several clock cycles before an error indication. Operations performed on this erroneous information are undone using a hardware mechanism for fast rollback of a few cycles. The authors discuss the implementation of a VLSI processor capable of micro rollback as well as several critical issues related to its use in a complete system.<>