Re: Apple II 5.25" floppy disks ...

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <4jpvmu$oh3@engnews1.Eng.Sun.COM>,
Mark S. Young <marky@Eng.Sun.COM> wrote:
> Did the Apple II (or variations of it) ever end up using something besides
> the 40 track 5.25" floppy ?  I'm not interested in the 3.5" versions
> that later showed up.  

The standard format was actually 35 tracks, not 40.  Most Apple drives
could do at least 38 tracks, and some third-party ones could do 40,
but supporting these required patches to the operating system.

Apple never made any changes to the 5.25" format for the Apple II, and
went to 3.5" drives (400K single sided using GCR encoding, then 800K
double sided, and more recently 720K/1.44MB high density using MFM
encoding).  The 400K drive was used on the second version of the Lisa
and the original Mac models.  The 800K drive was released for the Mac
Plus and an external one was also available for the Apple IIe/IIc.

There was one other use of 5.25" disks: the original version of the
Lisa used a weird double-sided 5.25" drive nicknamed "Twiggy".  I
don't know much about it, except that I think it had two heads, with
windows on opposite edges of the disk jacket.

There have been various third-party drives and controllers which made
use of other formats.  MFM double sided double density 5.25" disks
(360K) could be used with a PC Transporter and TransDrive, or with an
old third-party drive controller.  More recently, the BlueDisk card
allows the use of any PC floppy drives, including 1.2MB 5.25", 1.44MB
3.5" and 2.88MB 3.5".


-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand