On 06/23/2018 04:53 PM, Fred Cisin via cctalk wrote: > I had hoped that Chuck would have an answer. > > If you have two disks that are nominally the same, and one works and the > other doesn't, then there is obviously something different. > > If the sector contents are the same, then the next step would be to > examine the headers, gaps, and addressmarks. > > For example, > if the gap after index pulse, before the first sector ofeach track is > too short, then it may not be able to read the sector header of the > first sector. (A serious and common problem with NEC-style FDC, not > usually a prolem with WD-style FDC) > > Do you have a way to examine the raw track encoding? > I used a track read with a WD 179x (slightly modified "Trakcess" on > TRS80 Model 3), and "TE" with the Central Point Option Board.
Find a copy of Anadisk and see what it reports regarding sector ordering. Also, you might try "sector" mode with the "Diagnostic Read" function, though that requires a bit of knowledge. Another thing to try is to grab a copy of Dave Dunfield's ImageDisk utility and see if it gets the copy right. You could also image both disks and compare the images. TeleDisk has a lot of "special case" code. People still have diskette drives? --Chuck