Warner Losh wrote:

leap seconds break that rule if one does things in UTC such that the naive math just works

All civil timekeeping, and most precision timekeeping, requires only pretty naive math. Whatever the problem is - or is not - with leap seconds, it isn't the arithmetic involved. Take a look a [EMAIL PROTECTED] and other BOINC projects. Modern computers have firepower to burn in fluff like live 3-D screensavers. POSIX time handling just sucks for no good reason. Other system interfaces successfully implement significantly more stringent facilities. Expecting to be able to "naively" subtract timestamps to compute an accurate interval reminds me of expecting to be able to naively stuff pointers into integer datatypes and have nothing ever go wrong. A strongly typed language might even overload the subtraction of UTC typed variables with the correct time-of-day to interval calculations. But then, what should one expect the subtraction of Earth orientation values to return but some sort of angle, not an interval? Rob