PROM Bugs

[Roger Heflin]

On Sun, 4 Jul 1999, Ludis Langens wrote:

> CSH-HQ wrote:
> > 
> > >The sad thing is - I've written a program that does 90% of the work to
> > >find these bugs.  I haven't needed to read and understand every line of
> > >code.  This does not say good things about GM QA.
> > 
> > Would this also, indicate that such "bugs", can run in a simulator just fine?.
> > Why, is it a sad thing?.
> 
> These buggy chips could appear to run just fine on a simulator.  (By
> simulator, I assume you mean your ECM test bench setup.)  If the bugs
> were bad enough to cause constant glitches, they'd have been caught
> during engine calibration.
> 
> It's sad because these bugs could be easily found through "mechanical"
> means.  In other words, a computer could have found them without human
> intervention or being programmed with specific knowledge about the chip.
>  Not finding these bugs is equivalent to building a high stakes race
> motor from a junk yard heap without magnafluxing.

I take it these are the standard array overflow/underflow bugs that
could be caught with something like purify?   If so, that is somewhat
sad since they are pretty easy to catch.

		Roger