23 Jun
2018
23 Jun
'18
11:16 p.m.
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