... but the way you've suggested would be VERY painful, and, not everyone who might want to acquire the data from an old 8" diskette wants to buy and learn to use a logic analyzer. A diskette with MFM-formatted data has, typically >>80,000 bit windows per revolution. Oversampled, say, 4x, means on the order of 256 kbits per track.

A logic analyzer capable of that many samples would not be cheap enough for, say, a hobbyist. It wouldn't fit in the budget for a researcher using 20-year-old equipment for a small portion of his work, either.

Many of the requests I've received over the years involving 8" media have involved hard-sectored media. These are often written with unique controllers using USRT's and NRZI data in proprietary formats unique to the often medical equipment they serve. I prefer to sample such things bitwise rather than trying to guess what's on the media. Of course, someone else has to do the "heavy lifting" of locating, isolating, analyzing, deciphering, and interpreting the data.

Sometimes, the task is "refreshing" the data, as was the case involving some aging medical instrumentation I dealt with some years back. The data simply had to be sampled, resynchronized with a consistent timebase, and written back to fresh media in order to ensure preservation of the data. Hospitals may be able to afford expensive equipment with which to do this sort of thing, but small clinics, particularly those in developing countries, cannot afford to do things the expensive way.

RE