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

[supertimer@aol.com (Supertimer)]

dempson@actrix.gen.nz (David Empson) wrote:

>Kenneth Edward Smith <cg591@torfree.net> wrote:
>
>> 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).
>> 
>> 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...
>
>I was under the impression that single density disks were not very
>reliable (in Apple II drives) and double density was preferable.
>
>This may have just been a quality control issue.

It was a quality control issue.  SS/SD, SS/DD, and DS/DD
all use the same magnetic coating.  The difference is that
they either test a single side or both sides and did density
testing to see how much the disks can hold.

The Apple II 5.25 drives are officially Single Sided Double
Density drives (SS/DD).  They stored more data than single
density drives and thus they became unreliable if you used
SS/SD disks.  Sure, most of the time it would have worked,
but not as reliably.

I still have old IIe and DuoDisk manuals.  Both pointed to
"DiskWare" blank disks that Apple used to sell.  Those
disks were SS/DD disks.  Double Density.