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