Information Technology Reference
In-Depth Information
Logical Tape Device Names
Logical tape devices are accessed via special files under the Raw Magnetic
Tape Devices directory,
/dev/rmt
. These files are actually symbolic links
from the special files associated with tape drives under the
/devices
directo-
ry. The tape drives are numbered starting with 0 (zero). Several files for the
same tape drive are usually present, each one providing an interface to the
tape drive with a different combination of density selection and rewind
option.
The tape density associated with a special file is indicated by an optional sin-
gle character after the tape drive number. Possible tape drive density indica-
tors are listed in Table 8.1. If a density is not specified, the tape drive will use
the default density, which is usually the highest density it supports.
Table 8.1
Tape Drive Density Indicators
Indicator
Meaning
l
Low
m
Medium
h
High
u
Ultra
c
Compressed
Following the tape number or optional density may be the letter
n
,
which
is used to indicate
norewind
. That is, after data is written to the tape drive,
the tape drive does not rewind the tape to the beginning. The tape is left
in its current position. The data written to the tape next will be written
after the date data. The absence of the letter
n
indicates the default tape
drive behavior, which is to rewind the tape when the writing of data is com-
pleted. The following shows some examples of tape drive names and their
meaning:
/dev/rmt/0 First tape drive, default density with rewind
/dev/rmt/0n First tape drive, default density with no rewind
/dev/rmt/2un Third tape drive, ultra density with no rewind
/dev/rmt/2l Third tape drive, low density with rewind
Be sure to know and understand the tape drive naming convention.
