On 22/08/2012 09:46, Martin Brown wrote:
On 22/08/2012 09:01, Mark wrote:
On Tue, 21 Aug 2012 16:30:52 +0100, PeterC
wrote:

On Tue, 21 Aug 2012 15:27:20 +0100, tony sayer wrote:

In article , Mike Tomlinson
scribeth thus
In article , Moonraker

writes

How accurate is the time given on Windows?

Depends on how accurate your motherboard's clock is. If the CMOS
battery is running low, it will lose time.

Or gain it. The only thing guaranteed is that there is a small
dependence on temperature and a smaller one on battery voltage. Most are
not properly trimmed and so drift +/- 15s/day worst case.

Some time sync software will show you the log of adjustments.

Windows can set the time from an Internet time server. On XP, the
procedure is to right-click on the clock, Adjust Date/Time, Internet
Time, enter 0.uk.pool.ntp.org into the box, then click Update Now. OK
your way out and Windows will set the time from a server
regularly. Of
course, you need to be online for it to work.


Look up Atomic.exe small prog that pings a ntp server every day.

Its also there in Windows 7 ..

Then take into account the effects of some software. The version of
Opera
that I'm running atm causes the clock to gain by about 5s between the
2-minute-interval ping of npl.

Please explain how it does this.

Who knows. It is more common for old games that disable PC interrupts
for long periods of time to make the main system clock run slow.

The typical daily drift on an untrimmed RTC chip from a 32kHz xtal is
about 15s or worse if the designers fail to put the right loading
capacitors round it. Depends a bit on ambient temperature.

I do find it annoying that some very expensive computer based kit does
not have correctly trimmed xtal RTC built in. The manufacturers fix for
this was to add GPS so that the unit can get a correct time as it boots!

Regards,
Martin Brown
Thanks for all the replies, I just wondered. Well now I know. ;-)

--
Residing on low ground in North Staffordshire