boot —
system bootstrapping procedures
Normally, the system will reboot itself at power-up or after crashes. An
  automatic consistency check of the file systems will be performed, and unless
  this fails, the system will resume multi-user operations.
On a NeXT, the boot procedure uses the boot ROM to load a boot program over the
  network using BOOTP and TFTP. The /usr/mdec directory
  contains a network boot program which should be made available via
  tftp(1). The network boot
  program will load netbsd from the NFS root as
  determined by the procedure described in
  diskless(8).
  - /netbsd
- system code
- /usr/mdec/boot
- boot program for NFS (diskless) boot