[Coco] error 249

[Gene Heskett]

On Saturday 18 March 2017 13:10:46 Bill wrote:

> So I should "DMODE /Dn stp=03 typ=03 cyl=50" and make sure the dns=1.
>
No Bill, although you may have to do that to get a wrongly formatted disk 
to read correctly. In that case read it out to mass storage, with dsave 
or? fix the descriptor, format the disk and write it back to get a  good 
copy on the floppy. But in the future, if cyl=50(80 decimal tracks) and 
the disk is a 5.25" disk, only then is it dns=3, indicating a narrow 
track drive, which if you put a 40 track disk in it, it should have a 
dns=1 and that will cause the driver to double step the drive, keeping 
the narrower 80 track head in the middle of the wider 40 track image on 
the disk so it can read that 40 track image properly.

To repeat, possibly add nausium, dns=3 only for the descriptor looking at 
a 5.25" 80 track drive, all other descriptors including the 3.5" stuff 
should have a dns=1.

You will thank us the first time you forget and try to write to that 40 
track disk in the 80 track drive, it will be write protected even w/o 
the notch being covered.  And your precious, only copy of the 40 track 
disk has not been destroyed.  All such bets are of course null and void 
if the descriptor that formatted that 40 track disk has a dns=3 in its 
lsn0. You can fix that with dEd. See my previous msg and the rbf defs 
and docs though.

> > -----Original Message-----
> > From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Tim
> > Fadden
> > Sent: Saturday, March 18, 2017 12:53 PM
> > To: CoCoList for Color Computer Enthusiasts
> > Subject: Re: [Coco] error 249
> >
> > If you are using this dmode on real floppies they will not work.
> > Dmode for 40 track 2 sided should be
> >
> > typ=20 cyl=28 sid=2
> >
> > formatted using a disk-based version of nos96809l2v030300coco3_dw
> > with no problems. I had copied Bill Pierce's utilities on it, and
> > was trying to access the disk while the Coco was running DriveWire
> > 4.


Cheers, Gene Heskett
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