vintage computers in active use

Ian wrote.... ----- When I suggested modernizing, I was told that changing the hardware would require *re-certifying the entire workflow*. In other words, it was far more economical to maintain a 70's era computer than spec, design, acquire/build and certify a new system. ----- Then Gene wrote... ----- Considering how military avionics systems work, this is entirely plausible. ----- Then Paul wrote... ----- Not only plausible but reasonable. ----- I can confirm first hand that it is not just plausible or reasonable - but factual. On occasion I have sold or repaired HP 1000 stuff for DOD branches and/or contractors. A time or two I discussed emulators or some type of modern replacements, asking why those weren't considered. They flat out said exactly what Ian said above: "When you're dealing with {insert name of lethal weaponry}, control systems must be known to function identically in every conceivable case and that certification process is exceedingly expensive". Usually followed by "we'll do it, after no more boards or repairs are to be had - but at that point those {weapon} systems may not be around anymore." Best, J