I've heard of a method to "unformat" a Commodore floppy disk, that's
formatted with the "quick" format. What is the procedure to do this,
and what can it recover?

Paul

On Jun 5, 11:13=A0am, dunric <lumberjack...@lycos.com> wrote:
> I've heard of a method to "unformat" a Commodore floppy disk, that's
> formatted with the "quick" format. What is the procedure to do this,
> and what can it recover?
>
> Paul

Basically, by reconstructing the track 18, where the directory is
stored, after scanning the whole disk for the files. I think to
remember there was a few utilities that made this easier. You can
recover most, if not all what you had before the format. The most
troublesome files are those whose entries were stored at track 18
sector 1, which is completely zeroed. I can't remember any tool name,
but I'm sure there are some out there.

Regards,
Rodolfo Leal

"dunric" <lumberjacks76@lycos.com> wrote in message 
news:8bb6b449-571d-4655-a511-bca6c94b550a@j12g2000vbl.googlegroups.com...
> I've heard of a method to "unformat" a Commodore floppy disk, that's
> formatted with the "quick" format. What is the procedure to do this,
> and what can it recover?
>
> Paul

Yes.

In theory anything not overwritten.  Often anything not on track 18.

A quick google yielded a couple of C64 unformats that I've never tested.

http://noname.c64.org/csdb/release/?id=65772

&

http://cbmfiles.com/genie/C64ToolkitListing.html


The CBM format has a pointer to the next track & sector as the first 2 bytes 
in each sector followed by 254 bytes of data.

So you could read though an entire disk, a sector at a time keeping track of 
each file segment, building a file list and rewriting the directory & BAM or 
write them to another disk.  If you know what you're looking for, you could 
also spot the start of BASIC programs or a load address for an ML program 
that you know.  The names would be missing.  If anything has been written 
over the disk you might find your data cut in half or over written entirely 
but than again, sometimes it's all there.  Sometime older versions are on 
the disk too.  Better than nothing.

Obviously, you should look around for existing utilities before reinventing 
the wheel because most stuff on the C64 has already been done.


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