vintage computers in active use

[Jay West]

Ian wrote....
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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.
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Then Gene wrote...
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Considering how military avionics systems work, this is entirely plausible.
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Then Paul wrote...
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Not only plausible but reasonable.  
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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