Ultrix-3.1/sys/distr/mkb.help3

3.  When making kits for field test or SDC submission, the
    system MUST be shutdown to single-user mode, as follows:

      o  Login to the `operator' account, shutdown to single-user
         mode, then escape to the shell by typing `!sh'.

      o  Mount all file systems by typing `/etc/mount -a'.

      o  Type `cd /usr/sys/distr', then `mkb' to begin the build.

      o  When the build completes, exit from mkb and dismount all
         file systems by typing `/etc/umount -a', then return to
         operator services program by typing <CTRL/D>.

      o  Type `r' to restart time-sharing, then <CTRL/D> to exit
         from the operator services program.