Help reading a 9 track tape
Len Shustek
len at shustek.com
Thu Aug 5 14:57:47 CDT 2021
> 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
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.
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