Large geometry MFM drive testing

[Chuck Guzis]

On 31 Oct 2010 at 10:15, Chuck Guzis wrote:

> On 30 Oct 2010 at 15:06, Steven Hirsch wrote:
> 
> > All,
> > 
> > I'm trying to evaluate a pile of large MFM hard drives for
> > functionality. I'm attaching them to a WD-1006V-MM2 controller and
> > running Sprinrite 4 under DOS 6.0 (using a 486 EISA motherboard).
> > 
> > This works fine for drives with < 1024 cylinders, but I cannot seem
> > to remember (or figure out) how to surface-test drives with more
> > cylinders (e.g. Priam V185 with 1166).
> 
> The convention when the cylinder field overflows 10 bits is to use the
> two high-order bits of the head field (that's why MFM, and for that
> matter, IDE drives max out at 64 heads when non-LBA geometry is
> used.).

I'll add that I was talking about the BIOS interface here.  Some 
BIOSes support this, such as the WD1006V-SR2 RLL controller.  But 
your MM2, I believe, has no on-board BIOS, so it probably doesn't.

If you'd like, I've got the source for a DOS driver that I wrote that 
handles cylinders 1024-1223 as a separate logical drive.  It might 
give you some clues as to how to work with this situation.

--Chuck