[Coco] Creating a Coco Floppy in DOS
cyouse at serialtechnologies.com
Wed Sep 17 08:44:29 EDT 2008
On Wed, 2008-09-17 at 05:08 +0000, wdg3rd at comcast.net wrote:
> -------------- Original message ----------------------
> From: Chuck Youse <cyouse at serialtechnologies.com>
> > I'm going to state something that might be obvious to some and not to
> > others. Be sure the 5.25" drive in your PC is a _double density_ drive
> > -- most every drive you come across these days is the 1.2MB AT standard.
> > They spin at a different rate and thus aren't very reliable readers and
> > even less reliable writers of double-density media.
> Extremely reliable readers, and very reliable writers _IF YOU BULK-ERASE THE DISK FIRST_.
I thought it was a data-rate problem, due to rotational rate. I.e.,
this problem doesn't exist between DD/HD 3.5" disks (720K and 1440K),
and they spin at the same rate. BUT they also have the same track
Hmm, so thinking about this for a moment .. double-density media has a
data rate at 300RPM of 250Kb/s. At 360RPM that becomes 300Kb/s, and
whaddya know, standard PC floppy controllers (like the 82077 on my FDC)
have a 300Kb/s data-rate option...
So I stand corrected :)
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