Re: DSK to NIB Instruction

[Jeff Blakeney <CUTjblakeney@sympatico.ca>]

On Fri, 14 Oct 2005 14:15:08 -0500, Ed Eastman <noone@nowhere.net>
wrote:

>Extra long tracks were accomplished by speeding up the drive when 
>writing the disk to fit more bits on the media.  (Faster = closer 
>together = more per track.)

I think you mean that the disk rotation speed is slowed down to get
more bits on the media.  If you speed the disk rotation speed up
without increasing the speed of the bit stream you send to the disk
you'll end up getting less bits on the media because each bit will now
be a longer magnetic pulse (or each bit will be farther apart
depending on how you look at it) and therefore will take more room on
the disk.

Spinning the media slower means that the bits will be shorter (or
closer together) and you can get more data on the disk.

Just look at the Apple 3.5 drive on the IIgs.  You get more data on
the outside tracks where the media is spun slower but as you move to
the inside tracks they have to speed up the media to make sure each
bit is long enough to be read by the hardware so you don't get as much
data on those tracks.

-- 
 Jeff Blakeney - Dean of the Apple II University in the
                 Apple II Community on Syndicomm.com
 CUT the obvious from my address if you want to e-mail me