Re: Defaults being destroyed

[Alexey I. Froloff]

On Tue, Aug 27, 2002 at 10:03:34AM +0100, Richard Frith-Macdonald wrote:
> In order to prevent this, I've added use of
> NSDistributedLock to NSUserDefaults anyway.
Uh... I don't think that NSDistributedLock is an ultimate
solution because of timeout (by the way, why 5.0?).

I have an idea about something like gslockd daemon, that
handles all interprocess locks. When lock is requested and
another process (or thread) already have this lock, gslockd
can check if lock owner still alive and so on... Here is irc
log of converatio with David Ayers...

<raorn> no. you set lock just like NSDistributedLock, and
        instead of making file-lock you ask this daemon for a
        lock. if file is already locked, daemon checks if lock
        owner still alive...
<dayers> But based on NSDistributedLock, there seems to be
         nochting wrong with implementing it using such a
         deamon instead of a file..... (ok answered)
<raorn> yes. and in this case we don't need timeouts...
<raorn> well, there can be another problem - what if gslockd
        itself dies? ;-)))
<dayers> Yes but what if gdomap and gdnc deis ....
<dayers> *dies
<raorn> they will be restarted
<raorn> so gslockd, but all information about existing locks
        will be lost
<raorn> or maybe not
<dayers> I gueass gslockd must also track it's lock in the
         filesystem also.
<raorn> depends on gslockd design...
<dayers> (But i could be singel file mapping locks to
         processes)
<dayers> (would you be imagining an DO Connection between them
         (I guess, cause that's what all other server use.)
<raorn> well, we have only one gslockd running at a time, so
        we can keep lock information in file...
<raorn> this all needs to be discussed in list...
<dayers> All processes should be registerd with gslockd. If it
         died, they would find out an register to listen to a
         Notificatin that it returned. gslockd would need gdnc
         to notify all processes that it was back up and
         loaded its cached locking file.

P.S. It's just an idea for now...

-- 
Regards, Sir Raorn.
AIF5-RIPN, AIF5-RIPE, Binec System Administrator.

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