[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