> On Aug 5, 2021, at 3:57 PM, Len Shustek via cctalk <[email protected]>
> wrote:
>
> > On Aug 5, 2021, at 8:39 AM, Jay Jaeger via cctech <[email protected]>
> > 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
I remember reading that -- nice piece of work indeed. Around the same time I
also saw a project along the same lines in Poland, which recovered an
interesting body of software for various early Polish machines.
One of these days we hope to read some 10-track 1/2 inch tapes from an
Electrologica X1, a very odd format that could be described as "DECtape with
variable length blocks".
paul
