Looking to read past EOT on DDS/DLT/LTO

Charles Anthony charles.unix.pro at gmail.com
Wed Jan 25 17:07:30 CST 2017

On Wed, Jan 25, 2017 at 3:04 PM, Chuck Guzis <cclist at sydex.com> wrote:

> On 01/25/2017 02:16 PM, Eric Smith wrote:
> > On Jan 25, 2017 12:24 PM, "Stan Sieler" <sieler at allegro.com> wrote:
> >> We have a friend with a "tape" (DDS, DLT, or LTO ... don't know
> >> which yet) to which was written a system backup.  Thousands of
> >> files, with an EOF between each file, and a double EOF + EOT at the
> >> end.
> >>
> >> The problem: They then accidentally overwrote the start of the tape
> >> yesterday with about 1 KB of data, plus EOT.
> >
> > I hope someone can prove me wrong, but I think that short of a major
> > effort to hack the drive firmware, the data is gone. Modern tape
> > drives are "too smart" to allow reading past logical EOT, and the
> > tape format is too complex to allow fooling the firmware by any
> > simple means.
> With nothing left to lose, I suppose that one might overwrite the EOT
> and then kill power during the write, then attempt to read backward from
> the end of the tape.
> I've never done it, but who knows?
Or do  it the data recovery way -- find a broken drive with a working
transport, hookup a A/D to the tape heads, stream the tape, capture the
flux, decode.

Not necessarily easy, tho.

-- Charles

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