More on tape drives

[Tony Cooper]

In article <1991Jun11.205058.799 at magnus.acs.ohio-state.edu>,
jtalley at magnus.acs.ohio-state.edu (James T Talley) writes:
|> I'm using the '/dev/rmt/tc4n' device to archive large transient files
|> that arrive on my system each night via UUCP.  My problem is that it
|> seems that you have to make all the writes in one pass.  As long as I
|> only make writes to '/dev/rmt/tc4n' device, I can continue writing
|> files to a single cartridge.  As soon as I use the 'mt' command to
|> reposition the tape, I start to get write errors and can no longer
|> write more files at the end of the tape.  If I rewind and start over,
|> I can start making multiple writes again.
|> 
|> This means I can continue using the cartridge to store more data as
|> long as I don't try to access the data that's already on the tape.
|> Any other access seems to make it read-only until I rewind and re-use
|> the whole tape.  I can live with this, if necessary.

I don't know what the FWB250 drive is but lots of drives let you write data
at the end of the tape and nowhere else. Where else would you want to write
it anyway? The only other place is in the middle and that means the rest
of the tape gets trashed. Some drives let you trash the tape this way,
others don't.

My tape drive tutorial (on jagubox.gsfl.nasa.gov) explains all this kind
of stuff. My st tape drive is smarter than the FWB one (skite, boast). 
It won't produce write errors when you try to do the writes. It prints a nice
English error message telling you what you are doing wrong.

Cheers,
Tony Cooper