MFM hard drive data recovery questions/ideas (help needed)

Andy Piercy andy.piercy at
Wed Jun 27 05:19:59 CDT 2007

What make is the drive?

Do the heads un-load?

If it's a Micropolis there is a know issue that is affects the drive over
the course of time which was pointed out to me and the fix worked a treat!

Have a look on the alias archive for "sticky bumpers".



On 27/06/07, Chuck Guzis <cclist at> wrote:
> On 26 Jun 2007 at 19:08, David W. Erhart wrote:
> > It's time to come up with a "Plan B".  Does anyone have a suggestion
> > about how to read the "raw" data from the MFM hard disk?  I was
> > thinking about putting in into an older PC based system with an MFM
> > controller and using some utilities to dump sectors to files that I
> > could convert into something readable/usable.  I haven't done this
> > before so I'm hoping someone smarter has a 'cunning plan' of how to do
> > this.  I'm a programmer and don't mind write some utilities to pick
> > apart the data after it's off the hard drive.
> David, I can only vaguely remember seeing Pinnacles when my firm was
> looking for micro alternatives to another VAX and 68K systems were on
> the list  We eventually ended up with a Plexus and were very unhappy
> with the performance.  Water under the bridge.
> I think the chances of a PC MFM controller making sense out of your
> hard disk are remote at best.   Address marks, CRC polynomials and a
> host of other variables generally makes for lots of incompatibility
> between controllers.  But it might give you some good information.
> By hooking the drive up to PC and then using INT 13 services to probe
> sectors at random, you should be able to determine if the drive will
> at least seek.  You'll get "sector not found" or "seek error" status
> back, but you'll be able to observe the drive and see if it's
> working.
> You can also try another MFM drive on the Pinnacle to see if it's at
> least accessed by the controller.
> What's the controller chip on the Pinnacle for the hard disk?
> Do you have any documentation on the system?
> Cheers,
> Chuck

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