Full-duplex I/O with a minimal number of intervening buffers required (i.e.
very low throughput latency), preferably accessed through a callback
interface like JACK's.  Last time I tried this it was quite complicated.
Maybe this has gotten easier in the last 2 years, but the docs don't seem to
be any different.
-Ben
  OK.
 So what exactly is meant here by "synchronized I/O"?
 Lee