Re: Need "Quad-Density" disks?

From: Anders Carlsson (
Date: 2006-12-29 09:11:05

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

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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