[Coco] disk drive/controller formatting question

[Ward Griffiths]

Do those drives possibly have a different precomp requirement than the stock 
drives would?  Format failing about the middle of the disk has in the past 
been related to that on some drives.

Ward

On 08/24/2005 08:10 am, Robert Gault wrote:
> Whichever way it works and doesn't work, Disk Basic and OS-9
> (particularly NitrOS-9) seem to require different amounts of precision
> from the drives. OS-9 on my system is much more sensitive to rpm than
> Disk Basic. With the latest NitrOS-9, we (Boisy's crew) have found some
> hardware won't format a disk at 2MHz and have changed the code so that
> the Coco slows down during format. Earlier versions of NitrOS-9 stay at
> 2MHz.
>
> Keep in mind that the interleave value can be changed in both Disk Basic
> and OS-9. So, if you think that may be the critical parameter, try
> formatting disks with a different value. Larger values of interleave may
> be easier for the drive. Values larger than 3 or 4 should not make any
> difference.
>
> Do both drives have this problem? Have the drive speeds been checked
> either with software or with the strobe markings? Are the head slides in
> the drives clean?
>
> Bob Devries wrote:
> > Arrgh. gremlins struck.
> >
> > I meant to say that formatting under OS9 works fine.
> > I remember that OS9 uses a different interleave for floppies, but would
> > that make the difference?
> >
> > ----- Original Message -----
> > From: "Bob Devries" <bdevries at gil.com.au>
> > To: "Cocolist" <coco at maltedmedia.com>
> > Sent: Wednesday, August 24, 2005 4:09 PM
> > Subject: [Coco] disk drive/controller formatting question
> >
> >
> > OK, guys, a curly question:
> >
> > Brian has a FD-500 controller with two Matsushita JA-551 drives. He can
> > read disks no problem, but formatting fails at track 17. This is under
> > Disk Basic.
> > HOWEVER, formatting under disk basic works fine!
> > What is different about the OS9 formatting that it will format disks ok,
> > but disk basic won't? He's using standard Radio Shack issued OS9 Level 2.
> >
> > Any clues?
> >
> > --
> > Regards, Bob Devries, Dalby, Queensland, Australia
> >
> > Isaiah 50:4 The sovereign Lord has given me
> > the capacity to be his spokesman,
> > so that I know how to help the weary.
> >
> >
> >
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > http://five.pairlist.net/mailman/listinfo/coco

-- 
Ward Griffiths				wdg3rd at comcast.net

"I predicted that if control of drugs were administrated by law
enforcement agencies, the result would be a black market more irrational
and widespread than that of alcohol prohibition and the growth of
enormous police-state repressive bureaucracy."	Dr. Timothy Leary