[Coco] 1.2 mb floppy

[Phill Harvey-Smith]

mike delyea wrote:
> Can I use my 1.2mb floppy with OS-9/NitrOS-9?  Could I split up my 
> 1.2mbfloppy into 2 720k drives or 4 360k drives?

Nope I don't think you can, you may be able to set the drive to run in 
standard double density, and then you would be able to use it as a 720K 
drive. What model of drive is it someone on here may have the correct 
settings for it.

> I read somewhere that you couldn't use the 1.2mb floppy to write coco
> or OS-9 360k disks.  This doesn't seem to be true because I used my
> 1.2mb to write my NitrOS-9 disks from an image.  

Yeah I have also done this with Dragon 180K disks, and had no problems, 
of course they where first formatted on the Dragon.

>						Does anybody know it
> the dmode numbers for the step rate are the actual step rate?  For
> example is stp=03 a 3ms step rate and so on. Whats the fastest step
> rate thats usable?  

That will depend on the drive I guess start with the slowest, do some 
tests that access files on the disk, such as running programs off it. If 
that seems ok, use dmode to drop the step rate, then test again till it 
fails (if it fails, if the drive is up to 3ms, then it won't fail :) ).
Used this method to determine the correct step mode for the Dragon Data 
supplied drive units.

Chances are that it probably will work at 3ms, so you could of course 
set it to that and see if it works, and go the other way :)

oops, just noticed what you where actually asking, will leave the above 
in because it may also be usefull to you.

IIRC step rates are :-

STP=	
00	30ms
01	12ms
02	06ms
03	03ms

I think these are documented on the WD177x / WD279x data sheets.

Cheers.

Phill.

-- 
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.