Re: 800KB DD disk reliability in SuperDrives?

[Warren Ernst <wernst@gmail.com>]

On Feb 5, 5:47 pm, "geoff" <ge...@a2central.com.remove-hg4-this>
wrote:
>   To: Warren Ernst
>  > All,
>
>  > I'm starting to come to the conclusion that High Density SuperDrives
>  > (connected to a SuperDrive Controller, of course) do not reliably
>  > format 800KB Double Density 3.5" disks. I wonder if anyone can confirm
>  > or deny this in their personal experience.
>
>  > Here's my evidence.I have the following hardware:
>
>  > A ROM3 GS with a SuperDrive Controller, two SuperDrives, and one
>  > "regular" Apple 3.5" Drive.
>
>  > An enhanced Apple //e with a Liron card and two UniDisk 3.5" drives.
>
>  > A Windows PC with a known-good 3.5" drive. I have a formatting tool
>  > that manually verifies every block to weed out bad disks.
>
>  > A few jillion old HD and DD 3.5" disks.
>
>  > I can format the same HD 3.5" disks under Windows or ProDOS (Copy II
>  > +) and then run a Disk Verify tool and they all come up with no
>  > errors. I can format it MSDOS and then verify it good, then reformat
>  > it ProDOS and verify it good with every SuperDrive I have. HD disks
>  > that fail verification on one machine fail it on another machine.
>
>  > Similarly, I can format 800KB DD disks, and verify them, with the
>  > Apple 3.5" Drive on the GS and on both UniDisk 3.5" drives, and then
>  > reverse the disks with the machines and verify them again. Disks that
>  > fail verification on one drive will fail it on another drive.
>
>  > Finally, if I take a verified-good 800KB DD 3.5" disk and attempt to format
>  > it in a SuperDrive (as an 800KB disk, of course), the format invariably
>  > fails with a block error. This happens with both my SuperDrives. I can then
>  > reformat the "bad" disk with the Apple 3.5"
>  > drive and test it, and it verifies fine.
>
>  > The SuperDrives can *READ FROM* the 800KB disks without any problems.
>  > They will do a Disk Verify operation on 800KB disks without problems
>  > either. They seem to write files to the disks just fine too. They just
>  > can't seem to format them properly.
>
>  > Does this jive with anyone else's experience?
>
>  > -Warr
>
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Geoff,

Was there an answer in there? ;-)

-Warr