[Coco] Sierra Xmas 86 demo

[Bill Pierce]

The bad thing is that neither drivewire nor the emulators care one bit about the dns but it's set in the descriptors and drivers and the disks will error. If there was a way in the driver to reconize that it was an image and not a disk and to just ignor the dns, the problem would go away. Very few people are using real drives as more & more are failing. 

Bill P 

Music from the Tandy/Radio Shack Color Computer 2 & 3
https://sites.google.com/site/dabarnstudio/
Bill Pierce
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-----Original Message-----
From: Theodore (Alex) Evans <alxevans at concentric.net>
To: coco <coco at maltedmedia.com>
Sent: Mon, Dec 10, 2012 2:24 am
Subject: Re: [Coco] Sierra Xmas 86 demo


On 12-12-09 11:39 PM, Gene Heskett wrote:

> On Monday 10 December 2012 00:38:14 Theodore (Alex) Evans did opine:

>> The reason why is so that if you put 40trk media in a 80trk drive it
>> will read it properly.  While this is largely immaterial on 3.5" drives
>> (I actually do own a 40trk 3.5" drive so they do exist) going with dns=3
>> on 3.5" drives allows the same image and descriptor for 3.5" and 5.25"
>> 720k disks.

> You could get away with that UNTIL you go to read somebody elses properly
> formatted 3.5" disk and can't.

This is well covered ground on this list.  There are *logical* reasons 
for choosing both DNS=1 and DNS=3 for an 80 track 3.5" floppy under 
OS-9.  Unfortunately, as a direct result, 720k images (mostly for 3.5" 
disks) exist using both conventions.  It sucks.  The situation has been 
there since people started using 3.5" floppy drives with their CoCos and 
it isn't likely to go away.  Since 3.5" floppies are neither 48tpi, nor 
are they 96tpi, neither side is wrong, and to claim that they are is 
only being a source of friction in the community.


-- 
Theodore (Alex) Evans

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