Thu Mar 15 07:45:21 CET 2007
> This is debatable.
> Semaphores are a rather dangerous and low level construction,
> and Erlang is not really supposed to be a dangerous and low level
Indeed the programming model of Erlang is strongly based on message
passing, which can be an *alternative method* to semaphores for
programming concurrent systems (see the Tanenbaum's book "Modern
> But for most purposes, Erlang *doesn't* share data.
Maybe someone reminds that, at the last EUC, the talk by Enzo Nicosia on
programming robots with Erlang presented the possibility (or necessity)
to have a *native support* for sharing simple data among processes. This
was due to avoid the latency of message passing between processes that
need/share the same information (this latency is dangerous for a
I would let you know that, in the software that we are writing for our
next robot (see http://eurobot.diit.unict.it), we are trying to overcome
latency problems without adding any data sharing support: the key point
is to improve process dynamics and performances by rewriting a 'clone'
of some OTP behaviours (gen_fsm and gen_server). The code of our
behaviours is small and fast, it does dot feature *all the same*
characteristics of gen_fsm/gen_server but only what we strict need for
our robots. And till now it's working good!
We will let you know the results ;-)
Eng. Corrado Santoro, Ph.D.
University of Catania - ITALY - Engineering Faculty
Tel: +39 095 7382380 VoIP: sip:
Personal Home Page: http://www.diit.unict.it/users/csanto
NUXI Home Page: http://nuxi.diit.unict.it
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