Hybernation and running applications

Derek Broughton news at pointerstop.ca
Mon Mar 31 02:15:38 UTC 2008


Arnold Weber wrote:

>>> That would depend on the program (which software are you using?) but I
>>> would expect not. Have you looked at the software documentation to see
>>> if it can handle hibernation?
>> 
>> Huh?  Of course it will continue.  Hibernation simply stops _everything_,
>> then saves the state of memory.  When it resumes, it restores memory and
>> starts again.  If hibernation works at all, _all_ programs have to work.
> 
> 
> It will work for _almost_ all programs. Troubling are programs that rely
> on stable network connections (like instant messengers) or programs that
> are getting confused if time jumps ahead a few hours at once while running
> (but i don't know an example for this category)

Do you have an example in any category?  An IM program should simply tell
you it lost the network connection - which it did - but it would be a
pretty poor network app that couldn't properly handle a lost network
connection.  The network does get taken down during hibernation (at least
the standard version - I'm not sure about swsusp).  

Programs shouldn't have a problem with the time skipping ahead - as Florian
put it, it's just as if it took a very long time to get a time slice. 
Programs _do_ frequently react to the time going _backwards_ because that
can mean duplicate timestamps.  Dovecot is one app that I use that
automatically terminates its daemon if the time goes backwards by too much
(if it's just a few seconds, it sleeps until the clock catches up).  This
actually did cause a problem with hibernation, because my clock actually
gains time when powered off, and network restart runs ntpdate to reset it,
but the solution was simply to ensure that I slewed the time in manageable
steps.
-- 
derek





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