[Info-vax] K-mutex

[Bob Koehler]

In article <99c1d545-9fcb-45ed-b8e0-2e1f053ede86 at z17g2000vbe.googlegroups.com>, Jose Baars <peutbaars at googlemail.com> writes:
> On Dec 14, 11:18=A0pm, Pierre <pierre.... at gmail.com> wrote:
>> On Dec 14, 7:43=A0pm, koeh... at eisner.nospam.encompasserve.org (Bob
>>
>> the easiest way to emulate semaphores with the DLM is to use a lock
>> with a value block. this method is not fault-tolerant but neither are
>> semaphores (if a process crash before freeing the resource slot, this
>> slot may be totally =A0lost).
>>
> 
> Wouldn't the crash of a process holding an EX lock cause the lock to
> be released
> or freed by a dead lock search?

   Yes.  But there have been OS written that didn't do proper exit
   handling and one of them might have POSIX semaphores.  Or a semaphore
   implementation on VMS could use a lock value block containing
   information VMS has no understanding of.