Re: Need "Quad-Density" disks?

From: B Degnan (
Date: 2006-12-29 17:02:39

I rarely have trouble formatting and using regular "48" disks on an
8050/sfd-1001.  I have some original software that was manufactured for
8050 drives, I will check whether tracks/in is indicated, I don't expect
any label on the disk to indicate tracks/p/inch.  I don't have the
original sfd-1001 or 8250 test diskette.  This would be the best disk to
determine what CBM intended to be used with the drive.  I don't have one
in front of me now, but I don't believe that CBM diskettes have the TPI
printed on the labels.


> On Fri 2006-12-29 06:00, William Levak wrote:
>> Quad Density and High Density are both 96 tpi.
> The biggest question is whether any floppy disk manufacturer ever
> sold 5.25" floppy disks labeled QD, or if it is a designation
> invented by the users. Up to now, the handful brands I've seen
> are labeled 96 tpi DD or something similar (or 100 tpi in case
> of PET-DISK).
> By the way, the mechanism in 8050/8250 and I suppose SFD-1001 is
> referred to as a 100 tpi drive that formats 77 tracks. Sometimes
> it is said that only true 100 tpi floppies are known to work 100%
> in those drives, and that a 96 tpi DD floppy probably is a better
> substitute than a 48 tpi DD but not all the way. Is this true, and
> did any other brand than Commodore/PET themselves label their
> floppies as 100/77 tpi?
> (Hmm.. cross-list posting by William. Is that desired?)
> --
> Anders Carlsson
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