I haven't posted much lately because I've been pretty busy. I've been reading some of the Mac OS X developer's guides, including the kernel programming guide. It's like being reacquainted with an old friend after many years. The Mac OS X kernel is based in part on FreeBSD. The first kernel programming I ever did, back in 1985, was on 4.2 BSD variants. There was a time when I had studied every line of networking code in the BSD kernel, from the socket interface down to the device drivers, but I don't remember much of what I knew.