[erlang-questions] Erlang on multi-CPU board using USB

[Matthias Lang]

On Monday, April 16, Richard O'Keefe wrote:
> We're building an 8-ARM machine from two boards with four ARMs
> each, connected using USB (because the ARM chips in question have
> USB built-in but not Ethernet).  I'd like to run Erlang on this
> system as a cluster.  Has anyone done something like that?  I am
> (only just) aware of ethernet-over-USB, but I've never set up an
> Erlang cluster by any means other than IP.  Where should I start
> looking in the Fine Manuals?

One way to read your question is that you're ruling out running Erlang
distribution over IP. Why? I.e. why not run ethernet-over-USB, run IP
on that and then run distributed Erlang over IP as usual? That
approach doesn't require reading any Fine Erlang manuals at all,
though it does require fiddling with Linux, assuming you're running
Linux.

If you really want to run without IP, then one approach is to
implement your own Erlang distribution back-end using whatever method
you like for getting data between CPUs over USB.

We wrote our own distribution back end to let two ARM cores
communicate over VLYNQ (a Texas Instruments specific connection
between chips). My colleague Thomas did it all, I think it took him
roughly a week, including figuring out VLYNQ. He started by looking at
the 'uds_dist' example (included in the Erlang source tree) and
reading the chapter about distribution backends in the ERTS manual:

   http://www.erlang.org/doc/apps/erts/alt_dist.html

Matt