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.