Re: Problems in 1.3.93

Matti E Aarnio (mea@mea.cc.utu.fi)
Mon, 22 Apr 1996 20:25:59 +0300 (EET DST)


> It is interesting, has POSIX.???? mandatory locks?
>
> UNUX^{TM} contains a lot of such queer beasts.
> All the textbooks (well, maybe, not all, I've read nothing
> except for Stevens 8)8)) explain that nobody knows for what
> mandatory locking was invented. Nobody knows useful applications
> for SYSV IPC semaphores and message queues.

Semaphores are a must for shared memory processes,
where the memory has multiple writers (and readers).
Message queues are a great way to do IPC in pretty
clean manner.

These strange looking things have propably appeared
because they pleased somebody's theory-oriented mind,
and/or as a customer wanted them... (And we all know
that the paying customer is always right... Right ?)

> Unfortunately, linux should comply any standards.
> POSIX must be respected. The requirements of SVID are allowed
> to be ignored: linux is not UNIX, isn't it?

POSIX does not cover everything... One can do POSIX.1,
and to a certain degree also POSIX.2 (shells) at the MVS!

> Alexey Kuznetsov.

/Matti Aarnio <mea@utu.fi>