[Coco] Any idea of the floppy disk unit I can connect to a 26-3029 controller ?

Gene Heskett gheskett at wdtv.com
Wed May 20 01:15:59 EDT 2015

On Wednesday 20 May 2015 00:19:32 George Ramsower wrote:
> On 5/19/2015 8:30 PM, Gene Heskett wrote:
> > On Tuesday 19 May 2015 13:27:15 Michael Graham wrote:
> >> Most 1.44M drives will work, but you'll only be able to use them at
> >> 720k capacity.  If you don't have any 720k disks, you can tape over
> >> the density select hole on a 1.44M disk and use it as a 720k after
> >> a reformat.
> >>
> >> --Michael
> >
> > You either have unusual drives, or unusually soft magnetically HD
> > disks.
> >
> > With the hole taped over, most drives will cut the record current
> > because the DD disk is easier to write to.  The taped over HD disk
> > is not recorded strongly enough to keep.  Go find one you made a
> > year ago, or even 2 weeks ago and there's a good chance you cannot
> > read it today.
>   I'm curious. If a 1.44 drive and floppies were used in the 1.44 mode
> with 1.44 floppies and on a coco would that drive still work at all?
> I'm thinking if one were to use it exclusively, could it work without
> trying to cheat the system? Simply format 40 tracks single or double
> sided as we are used to.
>   Naturally, if this does work, the floppies would not be useable on a
> normal drive we are used to.
> George R

That 1.44 implies a 500 kilobaud data rate between the disk and the 
controller.  Unless a pretty invasive hack has been done to the 
controller, and only the 1793 equipt controllers (the original needs 12 
volts model) can be made to do it.  The rest of the 1773 based 
controllers are limited to a 250 kilobaud data rate, and that can only 
put 720k on an 80 track double sided disk.

There was a 2.88 meg format right at the swan song of the floppy, and 
that controller ran at 1 megabaud for a data rate.  Hard drive $ were 
coming down like a rock and wrote the ~30~ to the floppy only systems of 

Cheers, Gene Heskett
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Genes Web page <http://geneslinuxbox.net:6309/gene>

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