multiple dumps to single tape

Malcolm Kay malcolm.kay at
Tue Dec 16 01:28:22 PST 2003

On Tue, 16 Dec 2003 10:25, David Bear wrote:
> if I am writing multiple dumps to a single tape, is it wise to have mt
> write a setmark after dumping each file system?

When a process closes the tape device, if any data has been written,
the driver causes a FileMark to be written. If you opened the device
as /dev/nsa0 then mt would write a second FileMark so on reading 
back you would find a zero length file between consecutive dumps.

(if you use /dev/sa0 then the second FileMark will be written at the 
beginning of the tape effectively discarding previously written dump)

Malcolm Kay

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