The SGI version of PD can not play or record more then 2 channels. I've fixed the problem and it's now possible to play or record up to at least 8 channels.
There was a mistake in the file: s_sgi.c The AL calls at line 142 and 147 was wrong, the corrected code is:
ALwritesamps( oport, buf, outchannels * DACBLKSIZE );
and
ALreadsamps( iport, buf, inchannels * DACBLKSIZE );
Best regards, Peter Lunden