character   block    description
---------   -----    -----------
    -         4      (bt)     Bootstrap memory file system
    -         6      (nodev)  Generic Null Driver Entry (all "nodevs")
    -         7      (sd)     RDB/9920 Disc pseudo-driver
    0         -      (cn)     /dev/console
    1         -      (mux0)   HP27140 6-Port MUX
    2         -      (sy)     /dev/tty
    3         -      (mm)     /dev/mem, /dev/kmem, and /dev/null
    4         0      (disc0)  CS80 Disc
    5         5      (tape0)  9-Track Magnetic Tape
    8         3      (sw)     /dev/swap
   16         -      (pty0)   Master pty
   17         -      (pty1)   Slave pty
   21         -      (instr0) HPIB DIL
   22         -      (gpio0)  GPIO DIL
   26         -      (lpr0)   Ciper Printer
   27         -      (dmem)   Memory Diagnostics
   28         -      (diag0)  Diagnostics
   29         -      (ktest)  Kernel Test
   30         -      (st)     RDB/9920 Console pseudo-driver
   31         -      (mux1)   Mux Driver for Firmware Downloads
