Help reading a 9 track tape
Jay Jaeger
cube1 at charter.net
Fri Aug 6 11:45:55 CDT 2021
On 8/5/2021 2:57 PM, Len Shustek via cctalk wrote:
> > On Aug 5, 2021, at 8:39 AM, Jay Jaeger via cctech
> <cctech at classiccmp.org> wrote:
> > I know Paul well (we were contemporaries at U. WI). He does not do
> that very often. He did not indicate any issue with a fire at the
> building that contains his collection when I last spoke with him.
> >
> > He does not actually read "blocks". He reads the tape in an *analog*
> fashion, and then processes the results with software. That is how he
> recovered the IBM 1410 system tapes and diagnostics, for example.
> >
> > To be honest, I doubt that this content would be such that he would
> be likely to volunteer.
>
> Some years ago, inspired by Paul Pierce's earlier program in Java, I
> wrote similar software in C to decode the analog waveforms from tapes in
> a variety of formats: 7-track NRZI, 9-track NRZI, PE, and 6250 BPI GCR,
> and 6-track NRZI for Whirlwind.
> https://github.com/LenShustek/readtape
Cool!
For completeness, here is a link to Paul's 7 track recovery software
info (which is what I believe you are referring to - there is also an
older version.)
http://piercefuller.com/collect/a7tv.html
>
> As a one-time physics major, I *am* interested in the Schoonschip
> content. I've offered to James Liu to give it a go if he can't get
> someone like Chuck to read it in a more straightforward fashion.
>
There is also this one for 9 track drives:
https://github.com/jakubfi/ninetracklab
(There is an article out on the 'net that points to this project,
referencing use of a logic analyzer to capture the data, but today I am
having trouble finding it with my searching spells.)
JRJ
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