Tandem was doing the same thing as far as redundancy and ordering it's own maintenance. Tandem even had redundant CPUs that would execute instructions in lock-s

Tandem was doing the same thing as far as redundancy and ordering it's own maintenance. Tandem even had redundant CPUs that would execute instructions in lock-step and compare results. They were very popular in banks. There are stories of parts showing up without customers even being aware any hardware had failed because they were so reliable.