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Re: 800k disks possible at all?



In article: <4o422f$4fi@newsbf02.news.aol.com>  eadeans@aol.com (EADEANS) 
writes:
> 
> >>Actually, I think they did it by varing the speed at which the data
> is written to the disk, depending on how far out the head is from
> the centre of the disk.
> <<
> 
> This makes good sense. Apple used a similar scheme to cram over 800K on
> the 5 1/4 floppies for the original Lisa Office System computers (in
> 1983).

Weren't those "Twiggy" drives 400K?  They had two notches on the disk as the
read/write heads were not above/below each other.  The Lisa2 (or whatever 
it was called) had 400k 3.5" disks (single sided) which were soon replaced
by the 800k double sided ones.

> Does anyone know of a way to read or create disk images from old 5 1/4
> ProDOS disks on a PC? I want to convert my old //c Appleworks stuff over &
> use it on Clarisworks. I'm also going to try an Apple IIe on Mac emulator
> under Executor (on OS/2 virtual DOS) just for fun!

Yes, but you need an original Apple II of some sort, be it a whole machine
(II,II+,//e with Super Serial Card) or a IIc or IIc+.  Then get a bit of
software called ADT (for the PC) or MacADT.  Check out the 
comp.emulators.apple2 FAQ for more info.

>    Ed.
> TeamOS2 & ClubOpenDOC
> 
> 
-- 
John.
john@klatch.demon.co.uk



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