For what it's worth, I now have midi output working in Squeak on Linux. 
The source code is at:

http://spaceegg.dyndns.org/~soundmath/

though this is still pre-alpha, with many bugs and unimplemented
functions.  (On the plus side, I have lots of source code documentation,
thanks to doc++ :)

My code depends on the ALSA library (v 0.5.10 or higher) and implements
most of the stubs found in Ian Piumarta's sqUnixMIDI.c file.  Feel free
to check it out and, if you are very brave, compile it into the VM
following the INSTALL instructions.  And feel free to email me if you
want to discuss the source, or anything else pertaining to Linux midi
support.

I recently started working on porting the Siren midi functions to ALSA
as well.

William DeMeo

______________________________
spaceegg.dyndns.org/~soundmath

Lex Spoon wrote:
> 
> On the Unix port, only Linux and SunOS/Solaris are supported.  Most
> every Unix has its own sound API.
> 
> On the other hand, "PortMusic" seems to support no more platfoms than
> Squeak does already:  "PortMusic is open-source and runs on Windows,
> Macintosh, and Linux."
> 
> -Lex
> 
> Juan Manuel Vuletich <jmvuletich at sinectis.com.ar> wrote:
> > Hi
> >   It is interesting. But we already have basic sound i/o on most
> > platforms. I think the next step would be full duplex, multichannel
> > audio with guaranteed sync between inputs and outputs, and low latency.
> > I think we need ASIO support.
> >
> > "Stephen T. Pope" wrote:
> > >
> > > Hey VM hackers -- check this out!
> > >
> > >         http://www.cs.cmu.edu/~music/portmusic/
> > >
> > > --
> > >
> > > stp
> > >   Stephen Travis Pope
> > >   http://www.create.ucsb.edu/~stp
> >
> > --
> >                    Juan Manuel Vuletich
> >                 jmvuletich at sinectis.com.ar
> >      Español: http://www.sinectis.com.ar/u/jmvuletich
> > English: http://www.sinectis.com.ar/u/jmvuletich/studio.html