Hi Brian,

(Disclaimer - I wrote this years ago:
https://www.brutman.com/Diskettes/Diskette_handling.html)

The drive is a DSDD (360) drive.  The media is DSDD as well.  I've used it
for a lot of disk archiving over the years.

I might have a speed or timing problem given that I'm using a 386, but
Teledisk really shouldn't have a problem with that.  It is possible that I
have a slight misalignment somewhere, so moving to another PC might work.
I want to get it figured out without resorting to Kyroflux or anything
esoteric like that.

I'm still marveling that it works.  The DVI is a wonderfully strange
beast.  I'm going to need to get a second drive on it because doing disk
copies 4 or 8KB at a time is going to get old really fast. :)


Mike



On Tue, Dec 10, 2024 at 11:06 AM Brian K. White <[email protected]>
wrote:

> Is the disk a SD/DD media or HD (360K or 1.2M)?
>
> Is the drive that you used to make the disk a 360K or 1.2M? Maybe the
> thinner 80-track head on a HD drive doesn't make a good enough disk vs
> the fatter 40-track head on a SD/DD drive.
>
> Or using a 1.2M drive might be good enough only if the disk is wiped
> clean with a bulk eraser (not just erasing/formatting in the drive). To
> write a 40-track disk in a 80-track drive, the drive still writes only a
> 80-track-thin track and double steps and skips over every other track,
> basically writing new data interleaved with old junk. Even if you format
> & erase first, there is still at least formatting in between your new
> tracks that might not line up so exactly that it doesn't blur the
> formatting on your actual data track.
>
> When the same 80-track drive reads that disk back, it has an 80-track
> head and so does not see the neighboring junk tracks, and you get a
> clean read. But when a 40-track drive reads that disk, it has a fatter
> 40-track head that spans 2 tracks, so it reads junk.
>
> Even with a bulk eraser to make it so that there is nothing at all
> between the new tracks, it's still a thin track making a weaker signal
> than the old drive is designed for.
>
> If you do have both a 360K disk and a 360k drive, you could try just
> cloning your own new working disk and see if that works. Maybe the image
> Steve posted isn't 100%. I don't know if anyone has yet claimed to
> actually use it to reproduce a disk. Even though you can now make copies
> with the DVI, it would be good to have a known working downloadable
> image too.
>
> Even you don't have a 360k drive in your dos machine, you DO have a 360k
> or 180k drive in your DVI. You could try using that drive in the dos
> machine and see how that goes.
>
> --
> bkw
>
> On 12/9/24 23:29, Michael Brutman wrote:
> > Posting a happy ending ...
> >
> > Brian hooked me up with one of his cables and boot diskettes and
> > everything is working as it should now.
> >
> > Apparently my 386-40 running Teledisk 2.16 can't create the DVI disk
> > image.  I was able to make a backup copy of the boot disk directly from
> > the Tandy/DVI combo so I'm safe for now, but I'd like to understand why
> > Teledisk didn't work when it should have.  The only thing that is
> > unusual about my system is that I have a Central Point Option Board in
> > it, but I've never had that cause a problem before.  And the first few
> > sectors were fine as the DVI booted from it; it just couldn't continue
> > and transfer disk BASIC to the Model 102.
> >
> > If anybody out there has used Teledisk to create a diskette recently,
> > what machine type (XT, AT, ?) did you use and what version of Teledisk
> > did you use?
> >
> >
> > -Mike
> >
>
>
> --
> bkw
>

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