Extracting files off “unknown” 8 inch disks. Any thoughts…

Terry Stewart terry at webweavers.co.nz
Wed Mar 22 17:49:01 CDT 2017


I’ve posted this to the VCF too…apologies for cross-posting.

I’d be grateful for any guidance or comments anyone could give me on this

Guys in the building next door to me (a Science lab) have found some 8 inch
floppy disks.  They want to see what’s on them, or at least to archive
them.  They have no idea what machine these disks were used with, or the
software was used to write the files.  They may be CP/M, or some other
format entirely.

I’ve got little experience with 8 inch drives or disk formats.  However I
have got a bare 8 inch floppy drive (a Mitsubishi M2896-63 Half Height
8inch DSDD), and also a CP/M computer with 8 inch drives (A Panasonic
JD-850M).  I’m thinking it might be an interesting challenge/project to see
if I can read these disks and get files off.

However, I imagine given all the unknowns it won’t be easy…perhaps even

I see two possible approaches.  One is to wire up the 8 inch drive to an
MS-DOS machine.  I’ll have to build/get a PSU for the drive so it can
supply the necessary 24 Volts required.  I’ll also have to make up a
special drive cable.   That info is available.  In fact, Chuck gave me some
tips a year or so ago.   However, once I’ve got the drive successfully
wired up, I then need to somehow analysis the disks to see what format they
are in.  Does anyone know of any software that will do this?  I’m aware of
disk22, for reading KNOWN CP/M formats but is there anything out there that
will analyse a disk from scratch?  Search the web has thrown up a few
possibilies (MMCPC, Cpmtools) but I haven’t explored them at all.

The second approach is to use the Panasonic JD-850M, and find a CP/M
program that will analyse an “unknown” 8 inch disk and read files from said
disks into the CP/M environment.  I’d somehow get the program into one of
my Panasonic 8 inch disks (just how, I’ll need to figure out).  I’d also
need to figure out how to get the files out of that environment also.

Anyway, has anyone else faced this kind of challenge and what are your
thoughts?  I don’t want to start unless I at least have some chance of
success.  I’m not hopeful.  The more I read the more you seem to need real
forensic skills and something like Kyroflux that works at low-level.


Terry (Tez)

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