[Coco] Copying over an IO ERROR

[John Riddle]

Hi,
I keep forgetting to mention this, but one thing you could try doing to see
if you can recover any data on a track with bad sectors is to read the full
track image using the disk controller's "READ TRACK" command.  IIRC there
is a program called "READTRAK.BIN" on Sportsware's Super Disk.  I went
ahead and checked and it is in fact in the Coco Archive, in the
Disks/Utilities subdir.. the manual is too, in
Documents/Manuals/Utilities.  Basically what it does is read the track
image in, which includes all of the data that describes the layout of the
track and the sector data itself.  The problem is, however, that that
utility doesn't allow for saving anything back to disk.  Now that I'm
thinking about it, I remember Tim Lindner wrote a utility to read in track
0 on Diecom's protected disks - utilizing the READ TRACK controller command
- no reason why that couldn't be used to read in a regular track and take a
look.  You'd even be able to easily modify it to save back to disk any
recoverable data.
I think that the Coco DSKCON disk I/O routines in Disk Basic will error out
with an I/O error on anything wrong at all with the sector on the track
(which could be caused by a number of different issues, even the sector
data being one byte off causing the CRC check to fail).
John

On Tue, Feb 3, 2015 at 7:09 PM, Allen Huffman <alsplace at pobox.com> wrote:

> > On Feb 3, 2015, at 6:01 PM, Bill <cwgordon at carolina.rr.com> wrote:
> >
> > By using a modified version of what Allen showed me, I've been able to
> get all (but one) of the 1984 Rainbow on Tapes onto a .DSK image.
> >
> > Now only a hundred or so to go <grin>
>
>
> Now — the gotcha is any bad sectors are skipped, and if they had data, you
> end up with files that are missing inside. I made mine write out a sector
> of “******”s for bad sectors, so later I could identify which 256-byte
> blocks of data were gone.
>
> I also had a second version that copied all the files using the COPY
> command instead of sectors. I knew some disks might only give me one shot
> and then I could never read them again, so I started with a
> sector-by-sector copy. Then, if there was an error, I would do a second
> attempt just getting files — an easy way to identify which file was bad.
>
> I have things I have lost forever, but fortunately, my RGB-DOS hard drive
> platter has backups of most of my floppies back then — including one disk I
> was terribly sad to see missing (custom graphics I did for a Houston Boat
> Show for my father, when I had first gotten the CoCo 3).
>
> Lots of gotchas along the way — but at least I have most of the files I
> wanted saved. Most, anyway.
>
> --
> Allen Huffman - PO Box 22031 - Clive IA 50325 - 515-999-0227 (vmail/TXT
> only)
> Sub-Etha Software - http://www.subethasoftware.com - Established 1990!
> Sent from my MacBook.
>
> P.S. Since 4/15/14, I have earned OVER $600  in Amazon gift cards via
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>
>
>
>
>
>
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