Originally Posted by
Uplinker
Clock/counter overflow is not catastrophic. Nor should the shut down potential of a clock/counter/register overflow need to be carefully checked for, because it should never be an issue in the first place.
Computer systems failed all over the world a couple of years ago when there was a leap second. More will fail this year when the next leap second happens (I know a couple of mine will, so I'll have to shut them down before midnight, and restart after). Clocks suddenly jumping back can have really bad consequences on all kinds of code which expects the clock to start at 0 and only ever increment.
We also had a similar issue a few years ago with some hardware we bought which started spewing errors after being in operation for about four years. Turned out that, although their clock was 64 bits, someone had unintentionally copied it to a 32-bit variable and then copied that back to the 64-bit variable, so the top bits were always zero. The things you don't test are usually the things that don't work.