[Coco] Floppy - less boot , was Re: VI and VIRQ

Alex Evans alxevans at concentric.net
Wed May 14 18:35:26 EDT 2008


On  14  May 2008, at 4:55 AM, Gene Heskett wrote:

> To format and use an 80 track 3.5 drive, do NOT change the dns  
> value in the
> descriptor, only the cyl(inders) to 50(=80 decimal) tracks.  There  
> is never
> any need to double step the 3.5" drive, they are all 135 tpi.

This is a problem that we will never get everyone to agree on.  If  
you are only using 3.5" disks that you have made with your particular  
setting, it doesn't matter which one you use (so long as you are  
consistent), if you are trading disks around they you need to have  
the same setting as people you are trading with.  Personally I think  
that the format for a DSDD 3.5" floppy on the CoCo should be exactly  
the same as the format for a 80 track DSDD 5.25" floppy so that you  
don't need to have two separate disk images for them.  The fact that  
there may never have been any 40 track 3.5" drives (or at the very  
least no-one is using them on their coco) does not matter.  If there  
were 160 track 3.5" floppies (270dpi), then I would likely have a  
different opinion.  Then again some of my personal 3.5" floppies are  
83 track, but I wouldn't assume that any random person could read them.




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