Re: assistance with disk ][ and modern 1.2M floppies

[cg591@torfree.net (Kenneth Edward Smith)]

David Empson (dempson@actrix.gen.nz) wrote:
: Obsbedia2 <obsbedia2@aol.com> wrote:

: > << You can't use 1.2MB (high density) 5.25" disks on an Apple II (short of
: > getting a PC-compatible disk controller and high density 5.25" drive). >>
: > 
: > The Apple ][ compatible Franklin 2200 had internal 5.25" disk drives that
: > had larger capacity because they wrote extra tracks (about 40 by my
: > memory).  Would this also need Double Density disks, or could it use High
: > Density disks?

: Still double density.  High density 5.25" disks have about four times
: the density of double density disks: about twice as much data per track,
: and twice as many tracks (80 instead of 40).

: By comparison, high density and double density 3.5" disks are both 80
: tracks, but the high density ones have twice as much data per track.

You're correct, as I've observed you appear to be consistently; but in 
this case incomplete.

Actually, the original A2 and compatible drives used single sided 
single density diskettes; the double sided double density disks also work 
as you've noted but originally were far too expensive for common use by 
hobbyists... it was rumoured at the time that SSSD disks were the result 
of quality control procedures which, if a disk failed DSDD led to testing 
as SSDD, which if it failed led to testing as SSSD, which if it failed 
led to landfill...

SD disks were only guaranteed to hold a maximum of 40 tracks, and certain 
A2 compatible drives could use all 40 if DOS 3.3 was patched to use it.  
Quentin, Fourth Dimension as I recall could do this.

But enough useless trivia... we now return you to your regularly 
scheduled newsgroup...

Ciao, Ken Smith
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