[email protected] scripsit: > > In any case, most computer clocks aren't accurate to > > 1 part in 10^8, which is the discrepancy between > > Posix time and UTC time since the beginning of UTC. > > How many milliseconds is that?
It's 24,000 ms out of the last 39 years, or approximately 1,230,720,117,120 ms. That is one part in 0.00000002. > I am not worried about precision, I am worried about correct arithmetic. I agree that subtracting one value of current-posix-millisecond from another has a rather small empirical probability of being off by 1000 ms, namely 1 in 10^-8. I have added a note to TimeCowan saying so. Note that 1 ms resolution does not necessarily imply 1 ms precision: in most Java implementations, you get 1 ms resolution but only 1 s precision. As for accuracy, typical computers with access to the Internet can be made accurate to about 35 ms, if carefully watched. > You are *forbidding* an implementation to increment the clock before > a leap second? Yes, absolutely. UTC time is readily available (except during leap seconds), TAI time is not. -- John Cowan [email protected] http://ccil.org/~cowan No man is an island, entire of itself; every man is a piece of the continent, a part of the main. If a clod be washed away by the sea, Europe is the less, as well as if a promontory were, as well as if a manor of thy friends or of thine own were: any man's death diminishes me, because I am involved in mankind, and therefore never send to know for whom the bell tolls; it tolls for thee. --John Donne _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
