Help reading a 9 track tape

Len Shustek len at
Thu Aug 5 14:57:47 CDT 2021

 > On Aug 5, 2021, at 8:39 AM, Jay Jaeger via cctech 
<cctech at> 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.

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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