Reading non-MFM disks in PC without special controller

From: Marko Mäkelä (
Date: 2001-11-13 09:05:44

Hi all,

I think that this might be of interest here.  It might be possible to read
1541 disks on a PC clone without any special disk controller.  The
Disk2FDI program works on Amiga and Atari ST disks.


---------- Forwarded message ----------
Date: Sat, 10 Nov 2001 15:12:32 +0100 (Westeuropäische Normalzeit)
From: Wolfgang Moser <womo_at_d81_dot_de>
To: Joe Forster/STA <sta_at_c64_dot_org>,
     Michael Klein <michael_dot_klein_at_puffin_dot_lb_dot_shuttle_dot_de>,
     Nicolas Welte <welte_at_chemie_dot_uni-konstanz_dot_de>,
     Markus Brenner <minsti_at_freenet_dot_de>, Christian Link <C_dot_Link_at_GMX_dot_NET>,
     Andreas Boose <boose_at_Linux_dot_RZ_dot_FH-Hannover_dot_DE>,
     Marko Mäkelä <msmakela_at_cc_dot_hut_dot_fi>,
     Peter Schepers <schepers_at_ist_dot_uwaterloo_dot_ca>
Subject: Disk2FDI, I'm really impressed (fwd)

Hi scene leaders (a joke :-),

today I a discovered something really interesting. It seems to
be or to become possible to at least _read_ C=1541 (D64) floppy
disks with standard PC hardware without additional hardware (not
even a single wire).

Vincent Joguin <> discovered a
possibility to trick out the floppy disk controller in a very
special way, so that his tool Disk2FDI is able to read different
Amiga floppy disks into disk images. It is known, that there
exist some Amiga floppy formats (exotic MFM as well as GCR
encoded ones), that cannot be read with standard hardware. Until
now ... (more precisely until 1999).

Download the tool from and read
the technical docs included. He describes the way, how the
floppy disk controller (mis)-programming works.

It will become time to change the 'facts', that we tell the
people in the different C64 news groups. Although there's no
such tool available for C64 related disk formats, it may
probably be possible.

To say it directly: I'm _not_ going to start programming such a
beast for different reasons, mainly missing time.
But perhaps there are some good programmers out there, that are
able to do this job, if they are fitted with some useful sources
(2MGUI, fdutils (Linux), 1581-Copy) and the right idea

I include the mail that I just wrote to Vicent with a "thank
you" for this idea.

Wolfgang Moser aka Womo

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---------- Forwarded message ----------
Date: Sat, 10 Nov 2001 14:43:26 +0100 (Westeuropäische Normalzeit)
From: Wolfgang Moser <womo_at_d81_dot_de>
To: vincent_dot_joguin_at_m6net_dot_fr
Subject: Disk2FDI, I'm really impressed

Hi Vincent,

I can't believe, that I needed sooooo much time to discover your
tool or at least the idea of how to trick out the FDC.

I myself had a deep look into direct floppy disk controller
programming with creating a tool named 1581-Copy, that reads and
writes C64 related disks with standard PC hardware, but it can
handle only MFM encoded disks (although some tricks are needed
there, too).

  Download is possible via (full sources included):

  in the future it simply will be:

I myself spent months of thinking about different possibilities
of how to trick out the floppy disk controller, so that it
becomes possible to at least read GCR encoded disks of the C64's
standard disk drive, the C=1541. I must have overlook the hint
in Ciriaco's 2MGUI sources, as you mentioned in your
acknoledgements, although these sources have been the base for
1581-Copy as well as other low level libraries like Alain Knaffs
fdutils (Linux).

I just read the supplied documentation of Disk2FDI and I can
only say:

     I am really very impressed, thank you for this great idea
     (as well as Ciriaco, if it was primarily his).

Now I have to contact some people to tell them about
this. Perhaps I can find someone, who is willing to discover the
possibilities to write a similar tool for C64 related floppy
disk formats, because I myself will be very busy the next two 
years; I matriculated for a master of science study in parallel
to my normal work (>= 40h/week).

Wolfgang Moser aka. Womo

PS: Is it possible to obtain the sources of Disk2FDI?

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