# what about clockspeed and NTP ? - NTP

This is a discussion on what about clockspeed and NTP ? - NTP ; Hello I'm a bit confused with those 2 concepts for keeping computer on the right time : - ntpd - clockspeed and taiclock Is ntpd look at the computer's clock derivation like clockspeed do ? Is it a good idea ...

# Thread: what about clockspeed and NTP ?

1. ## what about clockspeed and NTP ?

Hello
I'm a bit confused with those 2 concepts for keeping computer on the
right time :
- ntpd
- clockspeed and taiclock
Is ntpd look at the computer's clock derivation like clockspeed do ?
Is it a good idea to have clockspeed and ntpd running together on the
same computer ?

Thanks for you lights,
cyrille

2. ## Re: what about clockspeed and NTP ?

Cyrille37 wrote:
> Hello
> I'm a bit confused with those 2 concepts for keeping computer on the
> right time :
> - ntpd
> - clockspeed and taiclock
> Is ntpd look at the computer's clock derivation like clockspeed do ?
> Is it a good idea to have clockspeed and ntpd running together on the
> same computer ?

It's never a good idea to let 2 different programs try to discipline the
system time in parallel.

As far as I know clockspeed can be used to compensate the drift of the
system clock continuously. However, you have to determine the amount of the
drift manually, and pass the correction value to clockspeed. The accuracy
you can achieve depends on the accuracy at which you have measured the
drift. E.g. you set the system time correctly and see how much it is off
after a couple of hours.

Ntpd can be configured to query the correct time from a reference time
source in regular intervals, so it can determine the clock drift by itself
and compensate it. The advantage is that you don't have to measure the
drift manually, and ntpd compensates the drift even if the drift value
changes, e.g. due to temperature changes.

Regards,

Martin
--
Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont
Germany

3. ## Re: what about clockspeed and NTP ?

On 6 nov, 15:40, Martin Burnicki wrote:
> Cyrille37 wrote:
> > Hello
> > I'm a bit confused with those 2 concepts for keeping computer on the
> > right time :
> > - ntpd
> > - clockspeed and taiclock
> > Is ntpd look at the computer's clock derivation like clockspeed do ?
> > Is it a good idea to have clockspeed and ntpd running together on the
> > same computer ?

>
> It's never a good idea to let 2 different programs try to discipline the
> system time in parallel.
>
> As far as I know clockspeed can be used to compensate the drift of the
> system clock continuously. However, you have to determine the amount of the
> drift manually, and pass the correction value to clockspeed. The accuracy
> you can achieve depends on the accuracy at which you have measured the
> drift. E.g. you set the system time correctly and see how much it is off
> after a couple of hours.
>
> Ntpd can be configured to query the correct time from a reference time
> source in regular intervals, so it can determine the clock drift by itself
> and compensate it. The advantage is that you don't have to measure the
> drift manually, and ntpd compensates the drift even if the drift value
> changes, e.g. due to temperature changes.
>
> Regards,
>
> Martin
> --
> Martin Burnicki
>
> Meinberg Funkuhren
> Bad Pyrmont
> Germany

Thanks a lot Martin. Now it's clear for me : I'll use Ntpd.

Cyrille