Session ID & Security

[Paul Rubin]

- c o v e n t r y - <coventry at removethisandallhyphens-o-n-e.net> writes:
> Why bother reinventing the wheel for a shared memory implementation
> when you could just use the filesystem like everyone is used to, just
> on a ram disk?
> 
> Linux and the BSDs have the capability to do this...

I'm not aware that Linux and BSD can do synchronous, atomic file
operations.  I'm not terribly up on this stuff though.  What semaphore
mechanism would you use?