Hello.  I would like my laptop's HDD to go to sleep, but ntpd writes
it's driftfile hourly.  If there anyway I can make it only write the
file daily, or only when it quits?  I have searched the internet for
some kind of solution  but nobody seems to be asking the same question.
 I realize I could disable the driftfile completely, but that is a last
resort solution.

Thanks,
Devin Bayer

At 10:14 PM -0700 2005-07-24, Devin Bayer wrote:

> Hello. I would like my laptop's HDD to go to sleep, but ntpd writes
> it's driftfile hourly. If there anyway I can make it only write the
> file daily, or only when it quits?

	I think that this would require a source code modification.


	Moreover, writing only once an hour should not be excessively 
onerous, even for a laptop. Yes, it will spin the hard drive down 
when it's not being used, but a laptop hard drive should be in use 
frequently enough that a single additional data write in a one hour 
period of time should not be noticeable.

	If this is not the case for you, you might want to look into an 
alternative storage mechanism for the driftfile -- perhaps a 
SecureDigital or CompactFlash card in a PCMCIA card reader that is 
plugged into the laptop. It should be easy enough to change the 
storage location of the driftfile as specified in your /etc/ntp.conf.

-- 
Brad Knowles, <brad@stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

 -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
 Assembly to the Governor, November 11, 1755

 SAGE member since 1995. See <http://www.sage.org/> for more info.
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Devin Bayer wrote:
> Hello. I would like my laptop's HDD to go to sleep, but ntpd writes
> it's driftfile hourly. If there anyway I can make it only write the
> file daily, or only when it quits? I have searched the internet for
> some kind of solution but nobody seems to be asking the same question.
> I realize I could disable the driftfile completely, but that is a last
> resort solution.
> 
Is there an issue about not writing the driftfile? There is no bad 
side-effect to failing to write the file. To change this would require a 
change to the source code and I seem to recall that it gets updated 
whenever the drift amount changes rather than just once per hour.

Danny

> Thanks,
> Devin Bayer
> 
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Thanks for the responses.  I'll submit it as a feature request.  As I
understand it the driftfile serves a purpose, so obviously there is a
bad side effect of not writing it.  I didn't take the time to
understand what that is, but the documentation said something about how
it could takes hours upon starting up before it figured out the
information stored in the driftfile.

-- 
Devin Bayer

"Devin Bayer" <devin.bayer@rochester.edu> wrote in message
news:1122313464.820672.37650@f14g2000cwb.googlegroups.com...

> Thanks for the responses.  I'll submit it as a feature request.  As I
> understand it the driftfile serves a purpose, so obviously there is a
> bad side effect of not writing it.  I didn't take the time to
> understand what that is, but the documentation said something about how
> it could takes hours upon starting up before it figured out the
> information stored in the driftfile.

The drift file stores the systematic part of the clock's frequency
error. Starting NTP without it means it has to converge to that first
before it can start tracking temperature changes and crystal aging.
You _can_ do without it.

Groetjes,
Maarten Wiltink

Devin Bayer wrote:

>Hello. I would like my laptop's HDD to go to sleep, but ntpd writes
>it's driftfile hourly. If there anyway I can make it only write the
>file daily, or only when it quits? I have searched the internet for
>some kind of solution but nobody seems to be asking the same question.
> I realize I could disable the driftfile completely, but that is a last
>resort solution.
>
>Thanks,
>Devin Bayer
>
>_______________________________________________
>questions mailing list
>questions@lists.ntp.isc.org
>https://lists.ntp.isc.org/mailman/listinfo/questions
> 
>
Devin,

if you put the drift file on a ramdrive, and in the startup time you 
copy the original drift file to the ramdrive, and at the shutdown time 
back to the hard drive, then it could be ok, and the HDD not used...

Adam
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Maarten Wiltink wrote:
> "Devin Bayer" <devin.bayer@rochester.edu> wrote in message
> news:1122313464.820672.37650@f14g2000cwb.googlegroups.com...
> 
> 
>>Thanks for the responses. I'll submit it as a feature request. As I
>>understand it the driftfile serves a purpose, so obviously there is a
>>bad side effect of not writing it. I didn't take the time to
>>understand what that is, but the documentation said something about how
>>it could takes hours upon starting up before it figured out the
>>information stored in the driftfile.
> 
> 
> The drift file stores the systematic part of the clock's frequency
> error. Starting NTP without it means it has to converge to that first
> before it can start tracking temperature changes and crystal aging.
> You _can_ do without it.
> 
It happens to me all the time as it can't write the file as it doesn't 
have permission. I've left it that way to remind myself to fix the 
permission issue.

If it fails to write, then it doesn't write, but life continues and ntpd 
 just works. There's no need to change the code to have it not write or 
write once-a-day.

Danny

> Groetjes,
> Maarten Wiltink
> 
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