Remember Pentium?
Passed “millions” of random tests
Boris Beizer created ten test cases from spec, third test exhibited the failure
Lesson: Specification knowledge beats “may be lucky” testing
Notes:
Q&A: THE PENTIUM FDIV BUG
Q: How many Pentium designers does it take to screw in a light bulb?
A: 1.99904274017, but that's close enough for non-technical people.
Q: What's another name for the "Intel Inside" sticker they put on Pentiums?
Q: What do you call a series of FDIV instructions on a Pentium?
A: Successive approximations.
Q: Complete the following word analogy: Add is to Subtract as Multiply is to:
4) On a Pentium, all of the above