[Coco] Sierra Xmas 86 demo

[Theodore (Alex) Evans]

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