HP 9000 Series 300 Tutorials Manual page 80

auto-addressing capabilities for many peripherals. Auto-addressing is
performed only on auto-addressed HP-IB device files. Some DIL subroutines
require a raw HP-IB device file, and will fail if you attempt to use them
on an auto-addressed device file. DIL subroutines that can be used
with auto addressed device files include hpib_eoi_ctl, hpib_eol_ctl,
io_burst, io_get_term_reason, io_lock, io_unlock, io_speed_ctl,
and io_timeout_ctl. Systems determine whether a device file is raw or
auto-addressed by the minor number used when the file is created. Address 31
(hexadecimal If) is reserved for raw files. Any address in the range 0 through
30 is auto-addressed. Refer to the appropriate appendix for procedures used to
create device and interface special files.
For example, suppose you are using a Series 300 computer with an HP 98624
HP-IB card on select code 08 to access a peripheral device located at bus
address 03. Use mknod to create a new device file named device for the
peripheral device and place the file in directory dev underneath the root
directory as explained in Appendix A:
mknod /dev/device c 21 Ox080300
3-20 Controlling the HP-IB Interface