Patents Assigned to Logicon Incorporated
  • Patent number: 5175847
    Abstract: A computer system having two processors (22, 24) with the capability of recovering program execution after a power supply interruption. The processors execute identical programs having executable segments. Control means (26) uses storage registers (38) to write segment initial instruction addresses into the trailing processor's program counter (34) so as to cause the processors to execute in adjacent segments. The control means also uses program wait loops to cause the processors to initiate the execution of each segment synchronously. The processors write to the same program variable, in a non volatile RAM (66, 76), only in alternate segments so that one processor, executing in an adjacent segment, forms a source of unaltered variable values for the other to use in recovering from a power interruption. A status register (36) provides segment completion status and a recovery table in a read only memory (62, 72) provides a list of variables that may be altered in each segment.
    Type: Grant
    Filed: September 20, 1990
    Date of Patent: December 29, 1992
    Assignee: Logicon Incorporated
    Inventor: Robert N. Mellott