I was asked a question about the 765 and I couldn't find a definitive answer. The question goes like this: "If the 765 is executing a "Read TracK" does it pay any attention to the sector ID address headers?"

If one reads the datasheet, the answer would seem to be "no"--it just reads the data fields, one after the other. So a good way to recover data from a track where a sector ID header is bad.

But I wasn't sure. So I dug around and found a floppy with a bad address header; i.e. one where the header CRC was bad. The data field itself was good.

Lo and behold, the "read track" simply skips the sector with the bad sector ID header--it isn't transferred at all. That the operation is paying attention to the headers does make a bit of sense, however. After all, it transfers the ID of the last sector read in the result bytes.

So there you go.