What ever happened to Tandem and NonStop OS 2092

As a software person, I don't care what happens between the START and the COMPLETE, as long as I know what the results are supposed to be and where they are put. It is an instruction black box to me. Now, if I have to think about two or more CPUs' black boxes before I can expect my next instruction to be executed, the system is incestuous and needs to be fixed.

It is difficult enough to wrestle with monotonically increasing PCs (program counters). If the hardware starts mixing them up in such a way that I have to know how it's mixed, then all efficient OS coding for the system is moot.

See above. If one CPU instruction end (not completion) depends on the business of another CPU's state, the computing is incestuous and will produce weird effects that will not be reproducible. And, honey, SMPing requires reproductive situations. Otherwise, the only good thing such a system can be used for is gaming.

Besides all of this, it makes adding, removing and reconfiguring impossible to do gracefully. I should be able to add-remove hardware without stopping computing service to all users not affected.

BAH