On Saturday, April 6, 2002, at 07:18 , Ken Williams wrote:
>
> On Saturday, April 6, 2002, at 01:23 PM, Nathaniel Irons wrote:
>> I just noticed that my mail scripts' exclusive locks don't command any
>> respect when the files to which they're writing live on an HFS+
>> AppleShare volume, in /Volumes/. Should I be surprised by this?
>
> Probably not - it doesn't work over NFS on most other Unix environments
> either. I'm not too familiar with AppleShare, though.
Network file locking strategies are best implemented in a way
that only those applications/daemons which are going to be
accessing files on the shared file system all agree to whether
it is an advisory lock or not.
Under SunOS we had the fun that the x86 variant machine had no problem
recognizing that a 'file lock' had been put down by the sparc machine
- it just never felt that it was anything more than 'advisory' - and
would go ahead and grab the house phone line and call up its UUNET
neighbors.... { this was the same code base compiled once for sparc
and once for x86... }
So if you are trying to 'exclusively lock' files from other
daemons/applications - you have to find out what they consider
to be full on 'exclusive locks' first - otherwise code around
the problem as best you can.
ciao
drieux
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