I shall probably change this, which I believe Helmut Eller probably introduced (in order for slime.el to have a usable entry point), to something somewhat simpler that permits either a filename or a port number to be passed to SLIME48-START, and coalesce SWANK-START & SLIME48 into one procedure that either uses a given port or prints a random port to a filename. I'll do this when I get CVS access, which will be rather soon now.