Help reading a 9 track tape

Al Kossow aek at
Fri Aug 6 12:01:46 CDT 2021

On 8/6/21 9:45 AM, Len via cctalk wrote:

>> 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.

The advantage of digitizing the output of the head preamp with a is you can do software 
AGC and sometimes do eyeball recovery of dropouts.

Disadvantage is for a long tape you need >128gb of RAM as a capture buffer, and even with lossless compression the captured data files
are quite large. The Saleae is also pretty expensive, but work really well.

More information about the cctalk mailing list