Subject: Re: Floppy driver
To: None <>
From: Brad Pepers <>
List: amiga-dev
Date: 02/28/1994 12:26:32
> > I think I know how to do it. There will be a bit or two in the minor #
> > which tells the driver what type of disk it is. Then the code that does
> > the track decoding can be different. What I'm not sure of though is if
> > the MSDOS disk ca be handled in the same way as the amiga (on a track
> > basis - not by sector).
> Best to do the following with minor device #:
> 	D = density: 0=low (720/880) 1=high (1.44/1.76)
> 	P = PC? 0=amiga (880/1.76) 1=pc (720/1.44)
> 	U = unit (0-3)

The density bit is not needed since the drive can be probed to find that
out. Also the PC/amiga could be probed as well (read a track and try to
decode using both methods - whichever one works is the proper type). But
I think I'll use a bit for this since the track format probe would take
a while.

> PC and Amiga formats both use MFM with 0x4489 as the sync pattern.  The
> track I/O code can be shared.  The sector decode code cannot.

Yes I think I will be able to do this by only writing two new routines
which handle sector <-> raw track for msdos type tracks.

> -- 
> David Jones, M.A.Sc student, Electronics Group (VLSI), University of Toronto
> email:, finger for more info/PGP public key

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+------------------ Brad Pepers -- -------------------+