Richard Bond on Tue 30/12 14:34 -0800:
> "By Design" is the official answer, to prevent overwriting
> data you have already saved.
> 
> [...]
> 
> 1. Reading it all in and then writing it all back out
> again are two more opportunities for entropy (and Murphy )
> to get at your data.
> 
> 2. tape heads have limited lifespans compared to the rest
> of your computers.
>
> tapes are cheap compared the cost of losing data and the
> labor to restore it.  Buy more tape, that's a better use
> of your time and money.

Um, both of those assume I've taken the tape out of the
drive and/or used the rewinding tape device.  Why not just
leave it at the current filemark and if it's still there at
same tell position on next run, just resume backup there at
next filemark? If tape leaves drive, just fsf to the
filemark that we left off at, no need to rewrite any data.
Don't see how this strategy would cause undue wear and tear
on tape device.