What is the difference between a rewinding, and non rewinding drive?
Well, the rewinding tape devices rewind the tape to BOT (Begin Of Tape) when the device is closed, i.e. tar -cvf /dev/qft0 /bin will rewind the tape cartridge when the tar job has finished. In contrast, tar -cvf /dev/nqft0 /bin will NOT rewind the tape cartridge and leave the tape R/W head at its current position. Rewinding devices should be used when performing a single backup, non-rewinding devices can be useful when doing multiple backups as one doesn’t need to space to EOM (End Of recorded Media) before appending another archive. Non-rewinding devices MUST be used when sending any of the tape motion command to the tape drive, such as mt -f /dev/nqft0 fsf , because when the mt process finishes then the tape device is closed which would result in rewinding the cartridge with the rewinding devices.
