Date   : Wed, 26 Oct 2005 19:06:32 +0100
From   : Sprow <info@...>
Subject: Re: BBC using 3.5 high density format

In article <d1c1b84c0510260715u2bd7de13mc932326e006f2353@...>,
   Paul J <peterbilt@...> wrote:
> Has anyone had a go at getting a 3.5 high density drive working at high
> density capacity ?
>  I found some interesting notes on an atari site, the atari st uses an
> 'ajax' floppy controller that supports double density, high density, and
> extended density floppys. 

I would suspect this isn't possible as the beeb doesn't use DMA to fetch the
data, every byte that comes from the disc causes an NMI. At the rate the
disc spins and the density the bits are packed at you end up with about 40us
per byte.

That's not many 6502 instructions, and half as many at HD,
Sprow.