Has the on-tape format of 98xx HP85 or 264x carts been documented somewhere?
Did HP use different encoding schemes in their different product lines?
I dug through the stuff on the 264x terminals that I just put up, and they
don't mention anything in detail about the tape format itself.
If you REALLY wanted to try recovering a bad tape, you could digitize the
analog info from the read amp and reconstruct it with software (assuming
you knew what the format was)
It may not be too bad with the HP DC100 style tapes, since I beleive the
heads are fixed, like the DEC TU58s.