What is the different between /dev/st0 and /dev/nst0 ???

Last week, our system meet a problem relate to backup data on tape.
Tape Drive has some problem, so that we need to erase the data on /dev/nst0 but actually we are backing up the data on /dev/st0.
Does anybody know the different between /dev/st0 and /dev/nst0 ???

I read on an ebook, and found that /dev/nst0 uses nonrewinding device file. Is that true ?

18.5.2. Device Files

Before discussing actual backup procedures, a word on so-called
device files is
necessary. When performing backup operations to tape and other removable media,
you must specify the device using its device file. These files are stored in
/dev and are understood by the kernel to
stimulate the use of device drivers that control the device. Archiving programs
that use the device files need no knowledge of how to make the device work. Here
are some typical device files you may find on Linux systems:


First SCSI tape drive

Did I Rewind That Tape?

When using tape drives, the kernel driver for devices such as
/dev/st0 and /dev/ft0 automatically sends a rewind command after any
operation. However, there may be times when rewinding the tape is not desirable.
Since the archive program has no knowledge of how to send special instructions
to the device, a nonrewinding device file exists that instructs the driver to
omit the rewind instruction. These files have a leading n added to the filename. For example, the nonrewinding
device file for /dev/st0 is /dev/nst0. When using
nonrewinding devices, the tape is left at the location just after the last
operation by the archive program. This allows the addition of more archives to
the same tape.

Source : LPI Linux Certification in a Nutshell, 2nd Edition.


One comment

  1. Another information from Linux Question Forum :both is indicate tape driver, and point into same device.The major difference is after perform a task, /dev/st0 will rewind to begining of tape, but the /dev/nst0 won\’t. normally we use nst0 for daily backup(unchange tape), nst0 for weekly/monthly backup (using single tape for each backup).Source : http://www.linuxquestions.org/questions/linux-hardware-18/difference-between-dev-st0-and-dev-nst0-493760/

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