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

Terry Stewart terry at
Fri Mar 24 20:18:13 CDT 2017

>I'll add one more note that an 8" drive supports 77 tracks/cylinders,
>where a 5.25" high-density drive supports 80.   So be careful.

Noted.  Everything is now ready waiting for those bits and pieces to arrive
from the U.S.

Last night I spent some time going deeper into IMD118, 22DISK and ANADISK.
I read the documentation properly and carefully.  I also played around with
the programs on the 486 using some known floppies and formats. I tried
different options and checked the images in a binary editor relating what I
saw with what the docs said should be there.   I now have a better
understanding of how these programs work and what they can tell/do for the

Dave D and Herb Johnston have some good info on 8 inch drives both in the
docs and the web.  The docs in 22DISK (Chuck's?) give some good info on
CP/M format configurations and how to determine unknown ones.

The MS-DOS 6.2 486 DX worked perfectly!

I'm looking forward to this project.  Even if I don't get anything off
those unknown 8 inch floppies I should be able to image my Panasonic
JD-850M CP/M ones.  That will be reward enough as they contain locally
written software and I'd like to archive it.

What might throw a spanner in the works is that the drive may be broken.
It looks fine but it is untested.  Guess I'll just have to wait and see.

Terry (Tez)

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