Formatting and verifying MFM hard disks

From: Marvin Johnston <marvin_at_rain.org>
Date: Thu Nov 27 23:33:38 2003

Well, debug g=c800:5 is one command, g=c800:6 works on another type of
controller, and the Xebec controllers are a strange lot that require
several entries to get into it. My memory has failed, so I don't recall
which address goes with what except that the Western Digital controllers
use the :5. On the "newer" versions of debug starting with either Dos
4.x or 5.0, doing a "debug /?" gives a short description of how to use
it, and a ? at the "-" prompt gives simple help. The way I always used
to find out the correct jump to address was to unassemble the address in
question; the correct address will be a jmp instruction.

Gene Buckle wrote:
>
> c800:5
>
> g.
>
> On Thu, 27 Nov 2003, Curt Vendel wrote:
>
> > Well, lets see.... if your on a PC, I think if you type at the DOS prompt
> > c:\> debug c800 that put you into the MFM controller firmware and you could
> > perform a low level format of the drive....
> >
> >
> >
> > Curt
> >
> >
> > ----- Original Message -----
> > From: "Ian Primus" <ian_primus_at_yahoo.com>
> > To: "General Posts" <cctalk_at_classiccmp.org>
> > Sent: Thursday, November 27, 2003 4:00 PM
> > Subject: Formatting and verifying MFM hard disks
> >
> >
> > > As I have been sorting and cleaning over Thanksgiving, I decided that I
> > > would build up an extra PC clone for the sole purpose of formatting and
> > > verifying various types of media, such as SCSI, IDE, and MFM hard
> > > drives and 3 1/2 and 5 1/4 floppies. I originally planned on just
> > > tossing an MFM card and SCSI card into an older AMD K6-2 233, and
> > > installing two floppy drives. But, as I got started, I remembered how
> > > the old MFM drive controllers worked, and how they kinda take over the
> > > boot process. Also, since MFM drives need to be low level formatted for
> > > a specific controller before they can be high level formatted, I can't
> > > really just format them from Linux. I found a Seagate card that has a
> > > nice boot screen with a drive formatting utility, but it only handles
> > > eight different Seagate drives. I've got a couple of other old
> > > controllers, none of which have such a nice utility, and all of which
> > > prevent me from booting from CDROM (they intervene before the BIOS
> > > boots from a disk, and when the MFM card can't boot a hard drive, it
> > > tries floppy drives, but it doesn't see the CDROM, and won't return
> > > control of the boot process back to the PC's built in controllers)
> > > Also, in this process, I realized that I can't find my DOS disks! It's
> > > been a long time since I booted DOS, and an even longer time since I've
> > > messed with DOS on XT's, so I don't know where the disks are. What I
> > > think I need is a disk with DOS 3.x and debug. I remember having to use
> > > debug to invoke the built in formatting program on most hard drive
> > > controllers.
> > >
> > > Anyway, what I really want to do, is have a computer that would have an
> > > MFM card in it, and be able to work with any MFM drive. I'd also like
> > > to still be able to boot off an IDE hard drive or a CDROM, since I want
> > > to install Linux on an IDE drive on the motherboard's controller, and
> > > use that for high level formatting. I can probably work around that by
> > > having a Lilo bootdisk, and booting that first, then the system could
> > > continue booting from an IDE drive. But, if I did this, what is the
> > > best way to do low level formatting on MFM drives? Is there a way to
> > > invoke the card's internal formatter from Linux? It's been a while
> > > since I worked with this stuff, can anyone refresh my memory?
> > >
> > > Thanks!
> > >
> > > Ian Primus
> > > ian_primus_at_yahoo.com
> > >
> >
> >
Received on Thu Nov 27 2003 - 23:33:38 GMT