The apple ][ didn't have the hardware to read the sync hole (much less a sensor to detect where the head was, hence the clatter on reset as the head bangs into the endstop). That was part of the magic, each sector had a sync field and then a few bytes and a track/sector number.

That is of course why its not just a simple case of locating where the burned hole was relative to the sync hole because the "physical" location of a sector offset on the disk would normally vary from disk to disk (or for that matter from track to track) or format to reformat.