Re: x86 Train Wreck
Unimplemented instruction traps going off to software implementations can have interesting side-effects.
First, an aside. The actual O/S calls on Dec10 (if not earlier) were implemented via UUOs. Bu I digress.
In the late 70's/early 80's, the research group I worked for started their Dec10 replacement plan. Put in a VAX 11/780 with the Floating Point hardware. Soon after it was installed, I left.
Then it was time for another system. Was it to be a VAX or an IBM? Now, Rutherford Lab having an IBM was quite the draw in that direction as it made data exchange easier, FP formats not being quite standardised as yet. So, benchmarks were run (you know where this is going now, don't you?)
The IBM 370/whatever that was being contemplated won, so it was ordered. Some time (months??) later during maintenance, it was discovered that the VAX FP unit wasn't functioning, and the FP instruction set was being transparently emulated. Fixed it, the VAX now out-performed the IBM. Red faces all round.......