27 Nov
2003
27 Nov
'03
7:33 a.m.
On Thu, 27 Nov 2003, Ian Primus wrote:
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.
ON XT.
On AT (You said AMD K6-2 233!), it is entirely an issue of what
your BIOS does.
(XT uses a BIOS extension ROM on the MFM controller card)
Also, since MFM drives need to be low level formatted
for
a specific controller before they can be high level formatted,
ON XT, there were a lot of mutually incompatible hard disk low level
formats.
ON AT, the format was standardized, and is the same for virtually all
controllers.
I can't
really just format them from Linux.
why not?
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)
If you set the CMOS in an AT to "NO DRIVE", then it will not try to invoke
the MFM hard drive.
IFF your BIOS supports booting from CDROM, then you can. And MOST AT
BIOSes that support booting from CDROM also support letting you choose
boot device.
XT's do NOT support CDROM boot, unless you add an additional ROM (such as
is present on some SCSI controllers for the purpose of booting from a SCSI
hard drive)
For DOS, you need 3.10 or newer if you want CDROM access (the CDROM is
seen as a very Local Area Network, and uses the undocumented network
redirector) (There was an aftermarket driver set for using CDROM with
earlier versions of the OS, but it might not be easy to find)
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
XT or AT? You mentioned "AMD K6-2 233", which would be a very unusual XT!
think I need is a disk with DOS 3.x and debug. I
remember having to use
3.10 or above if you want CDROM access
3.31 or above if you want access to FAT volumes larger than 32M
debug to invoke the built in formatting program on
most hard drive
controllers.
You could write a trivial program (5 bytes) to do a far jump.
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?
For DOS, "Speedstor"
Is there a way to
invoke the card's internal formatter from Linux? It's been a while
You could write a trivial program (5 bytes) to do a far jump.
since I worked with this stuff, can anyone refresh my
memory?
we all have our own "old-timer's disease" issues.