erratic clock behaviour in Windows XP
Posted on 2004-03-26
I administer a Dell Dimension P4 desktop running Windows XP Pro, SP1. This computer, like 5 others on the same subnet, is acquiring an NTP/GPS time signal via Tardis Time Server (running as a service). Occasionally, but with increasing frequency, this system clock on this machine becomes uselessly erratic. This erratic behaviour seems to fall into one of two categories:
1.) the clock spins forward at a rate of 15 sysclock minutes: 1 real second.
2.) the clock spins backward at a rate of 5 sysclock seconds: 1 real second.
This computer runs client software for a 911 Emergency Dispatch CAD system, so the accuracy of the timestamp of data sent from this computer to the CAD server is fairly important for legal purposes. Obviously, the timestamp of the data sent from this problem machine is worthless when the clock is behaving this way - which, these days, is at least once a week. A reboot usually resolves the problem for a period, but since this machine needs to be on and operational 24/7 (911 dispatch business requirement), rebooting in the middle of a 911 call is not always an option.
I see one of 3 options:
1.) some sort of NTP clock-variation suppressing software, that suppresses variations in time above a certain threshold, say 500ms.
2.) install some sort of monitoring tool to see if there is some specific circumstance that might cause a clock to behave in this way.
3.) buy a new computer - not really a feasible option, since Dispatch guys just bought this computer and probably couldn't make an argument for buying yet another.
There are 2 identical Dell Dimensions running the same suite of software on the same subnet off the same NTP time signal that are behaving just fine, so I've ruled out ambient heat or some other digital or physical environmental condition. I've tried a few shareware monitoring and suppressing utilities, but so far haven't found anything that is really helpful. Any thoughts, I'm all ears.
doublehorn - from the not-quite-so-frozen wilds of Southern BC.