[Coco] 3.5" Drive Variable in the NitrOS-9 Module Header

[Bill Pierce]

>The only thing you really needed to do for 80 track drives was to make sure
>you had typ=21 and cyl=50
>On the high density 5.25" drives you needed to change some jumpers is all I
>can remember at this point.  As far as 1.44MB 3.5" floppy drives if you
>used a real 720K floppy disk in it the detector switch automatically would
>set the correct data rate of the floppy drive to double density.

Also, to use a 3.5" 1.44m disk as 720k, you could cover the "HD" id hole on the disk and the drive would recognize the disk as 720k. The hole was opposite of the write protect slider. I used the old write protect stickers from 5.25" disks for this. If the disk had been "factory formatted" for IBM, most times you needed to use a bulk eraser to clear the disk because the drive eraser wasn't strong enough to erase those "factory formatted" disks.

Bill P






Music from the Tandy/Radio Shack Color Computer 2 & 3
https://sites.google.com/site/dabarnstudio/
Bill Pierce
ooogalapasooo at aol.com




-----Original Message-----
From: David Ladd <drencor at gamepixel.net>
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Sent: Sun, Jan 27, 2013 11:08 am
Subject: Re: [Coco] 3.5" Drive Variable in the NitrOS-9 Module Header


On Sun, Jan 27, 2013 at 6:53 AM, Wayne Campbell <asa.rand at gmail.com> wrote:

> I recall that, although I never saw one, 720K floppies did exist, both in
> 5.25 and 3.5 varieties. I'm not sure it will be worth it for those, except
> for completeness as they were rare back then (89-94). I think the greatest
> issue will be the high-density drives. The 5.25 variety is 1.2 meg instead
> of 1.44 meg. Will that make a difference to the driver?
>
> When I had my Coco3 I had 3 80-track floppies, 2 5.25 and 1 3.5. I found a
> 1.44 meg 3.5, but it was only usable as a 80-track 360K because the
> descriptors and driver wouldn't work with anything larger under OS-9 Level
> 2.
>
>
> <cut>
>

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