HP C100/110 89

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 Administration 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 compression 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 cassette 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.