Using Device Files - HP C100/110 Owner's Manual

Using Your Digital Data Storage (DDS) Tape Drive
Operating the DDS Tape Drive

Using Device Files

Your system has four default device files for use with your tape drive: two
device files for noncompressed mode and two device files for compressed
mode. If you use these device files, you do not need to create any device
files.
Device files are special files that tell your system which system hardware
pathway to use when communicating with a specific device and what kind of
device it is.
If the SCSI address of your tape drive is not set to the factory default of
SCSI ID 3, you must create a device file, then substitute the pathname of
your device file in the examples that follow. Refer to the System Administra-
tion Tasks manual for information on how to create a device file.
NOTICE: The device file names used in these examples are appropriate only for
systems running HP-UX 9.05. If you are using HP-UX 10.0, the device file
names will depend on the naming conventions of your particular system.
See "SCSI ID and Device File Information for HP-UX 10.0" in Chapter 1
of this book.
Device Files — No Data Compression
Your system has two device files for using your tape drive with data com-
pression turned off. The device files are named /dev/rmt/3m and /dev/rmt/
3mn, and are set for SCSI ID 3.
If you use the /dev/rmt/3m device file, the tape drive rewinds the data cas-
sette every time the system releases the drive from its control.
If you use the /dev/rmt/3mn device file, the drive does not rewind the data
cassette. The tape stays where it was after the last operation.
If you use these device files, you do not need to create any device files.
Device Files — Data Compression
If you wish to use the data compression feature, use the device files /dev/
rmt/3hc and /dev/rmt/3hcn, which are set for SCSI ID 3.
If you use the /dev/rmt/3hc device file, the tape drive compresses the data
and rewinds the data cassette every time the system releases the drive from
its control.
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