OT: Re: Computer loosing time

Mike Bird mgb-ubuntu at yosemite.net
Fri May 16 01:47:54 UTC 2008

On Thu May 15 2008 16:40:41 NoOp wrote:
> If your OS is relying on _the system clock_, and the clock is losing
> time, then it will use and report the time according to the system
> clock. If you have Ubuntu set for something other than UTC, it will
> periodically go out and get the time from the system clock. You'll see
> this option on install; whether to use the system clock or use UTC. Post
> the output of:

Linux takes the time from the system clock at boot, and writes
it back at shutdown.  While Linux is running the clock is maintained
by interrupts from a motherboard timer.

It is not uncommon for motherboard clocks to drift a minute per day.
I've seen them drift thirty minutes or more but that is rare.  If
you need accurate timing and if you're always online use ntp.

Sometimes motherboard clocks only drift under heavy load.  This can
be caused by interrupt problems, for example heavy disk activity
without "unmask-interrupts" (hdparm -u1 ...).

--Mike Bird

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