Windows clocks drift, jump or silently stop syncing more often than they should. How the Windows Time service actually works, how to find out what it is doing with w32tm and the event log, how to fix standalone machines, domain members and the PDC emulator, and how to use a Linux box running chrony (or ntpd/NTPsec) as a reliable time source for Windows.
Linux - The Next GenerationOpen Source, Linux, IT Stuff