Tape dumping programs for Unix/Linux..

From: Douglas H. Quebbeman <dquebbeman_at_acm.org>
Date: Thu May 2 18:10:22 2002

> However, if I notice recovered-reads (or hard errors) on old 9-track
> tapes, I often see fewer recovered reads (or hard errors) if I try
> the tape one more time. I assume that going over the heads once
> may have knocked off a bit of dust/dirt/something that affected
> the tape the first time. Note that I don't discard the
> results of the first run until the second run finishes...

hey! Me too!

> I've had one tape break during a second run :)

Ouch! Acetate backing?

> > > Go buy a 9-track drive and hang it on your *nix box.
> > > Let me send you a 9-track tape. You read it any way
> > > you want. You send me the tape back.
> >
> > > Then you go get a second tape, and put the data back on
> > > any way you want. Then send it to me, and I'll tell you
> > > if your technique works or not.
>
> BTW, the only way you can be *SURE* you got all the data on
> the tape is if *EVERY* read-request returned fewer characters
> than you asked for. E.g., if you did:
> bytesread = read(fromfd, buffer, BUFSIZE);
> and you get BUFSIZE bytes in, then there's a chance that that
> tape record had BUFSIZE + 100 bytes ... and you've just lost
> those last 100 bytes.

I *just* recently discovered this, and will incorporate that
into a utility I'll be hosting on the Prime.

-dq
Received on Thu May 02 2002 - 18:10:22 BST