This is Ken's optical-jukebox fileserver, expanded to 64-bit disk
addresses and quadruple indirect blocks, then ported to user mode.

The APC UPS shut-down code has been moved into a separate command,
watchapc.

To customise, set RBUFSIZE and choose 32bit.h or 64bit.h in dat.h, and
tweak localconfinit(), fsprotocol[] and startsb[] in conf.c.
