> > I need to read a non standard floppy format, and copy
> > disks with it.
>
> You could try reading from the "raw" floppy device with the 'dd'
> command. This should give you hints about how "PC compatible" the
> format of the disks are.
Very incompatible indeed :-( When it formats, it announces "80
tracks,
80 sectors". This doesn't match any option of fd, or fdformat that I
read about. Norton's diskedit (for bad old Dos or Win 95)won't even show
me numbers. A contribution from another mailing list (which I now
enclose)
>" Your dongle is formatting the 720k disk as such..
> 80 tracks (concentric circles on the disk)
> 80 sectors (pie-shaped wedges of the disk)
> and places 80 bytes of data on each sector.
> This layout is the same on both sides of the disk
> An unformatted 720k floppy can hold 1000k when blank
> You can see this is like saying exactly 1Meg.
> Your Dongle is giving you exactly 1Meg of Drawing Data not 720k
> like dos does."
>
has a go at explaining a possible format. Now I can hack or bodge my way
out of most problems, (like I repaired the $4000 card driving this and
have the machine going again) but on this one I'm still thinking. I'm
not even sure if it's 80 sectors per track, or per disk.
>
> Anyway, my idea is that using dd, similar to this example;
> # dd if=/dev/fd0 of=disk_image.raw bs=72k count=10
> would yield error messages (bad sector etc.) if the disk contains a
> non-standard ("PC-unreadable") format, and a valid disk image in
> the file disk_image.raw if it is just the filesystem that is
> unstandard.
I tried numerous combinations down to as low as bs=50 count=1,
but
although it did try, the result was the same always.
/dev/fd0: Device I/O Error
0+0 records in
0+0 records out
>
> I know way too little about how 3.25" floppy drives work and how
> programmable/controllable they are. Is there a way to for instance
> change the rotational speed? Do you control the step motor yourself,
> or do you just give the drive a track number?
>
I know little as well, but I bekieve on this particular machine,
speed
can be varied. The thing uses a WD1772 FDC controller chip. which does
have a 'step' pin which is toggled for every step of the stepper motor
>:-( I can get an oscilloscope scope on it while working if it bacomes a
big issue, and get an approximate soeed (It's one of those 'scopes :-)
>
> Does the external box that creates the floppies contain a
> "PC-compatible" drive too?
Yes. It only operates through the software package designed for
this
machine, and has no option to copy the bootup disks. I have recently
swopped both drives by buying an old XT compatible laptop and scrapping
it, and they have had a breakdown for a week - again floppy drive
related.
>
> Other things to try: amiga and macintosh.
The WD1772 chip can't handle the mac format. The WD 1772 was
used
in
the Atari, I believe....any Atari owners read down this far? I don't
know about the Amiga
--
Regards
Declan Moriarty.
