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NOTE:

This web site is not some kind of 'official' documentation hub for the XT-IDE card. It is simply the result of someone who decided to add to the documentation that exists elsewhere.

VCF XT-IDE  -  Coexistence with an MFM hard drive controller card



MFM hard drive controller of XT-class

It is possible for a VCF XT-IDE card to coexist with an XT-class MFM hard drive controller card.  The cards can co-exist because they are very different from each other.  A diagram showing the situation is at here.

For example, I have done it by adding an XT-IDE card to a clone XT computer of mine.  A photo of that configuration is at here.  I have also had an XT-IDE card coexisting with an IBM Fixed Disk Adapter, in both an IBM 5150 (10/27/82 BIOS fitted) and IBM 5160.

Booting

Background: The version of the XTIDE Universal BIOS (XUB) that I have fitted to the XT-IDE card is V2.0.0 beta 3+

So, by default, the MFM drive is the first hard drive and the XT-IDE's drive is the second hard drive.  The XT boots from the MFM drive (the first hard drive), with the MFM drive presented as logical drive C:, and the XT-IDE's drive presented as logical drive D:

If instead, I want to boot from the XT-IDE's drive, I would press the 'D' key when I see the Hotkeybar shown by XUB V2.0.0 beta 3+.  That will make the XT-IDE's drive be the first hard drive, and the MFM drive be the second hard drive.  As a result, the XT will boot from the XT-IDE's drive (now, the first hard drive), with the XT-IDE's drive presented as logical drive C:, and the MFM drive presented as logical drive D:

Optionally, if I want the XT to boot from the XT-IDE's drive by default (i.e. I don't need to press the 'D' key), I can do that by reconfiguring the XUB in the XT-IDE card, specifically, changing the 'Default boot drive' setting to 81 (eighty one).

IMPORTANT:	Make sure that the MFM drive is successfully booting in the computer before (repeat: before) you add the XT-IDE card.  That is because the XT-IDE card will default to booting from the MFM drive.
IMPORTANT:	The ROM in the XT-IDE card needs to be sitting at a higher address than the ROM in the XT-class MFM hard drive controller card.  That is normally the case  (XT-IDE card = D0000, XT-class MFM card = C8000).

MFM hard drive controller of AT-class

It is possible for a VCF XT-IDE card to coexist with an AT-class MFM hard drive controller card.  The cards can co-exist because they are very different from each other.  A diagram showing the situation is at here.


Background information

• The AT-class MFM controller/drive is software controlled by the BIOS on the AT-class motherboard.  That BIOS uses the C: drive type in the SETUP (CMOS SETUP) to determine the geometry of the MFM drive.

• The XT-IDE controller/drive is software controlled by the XTIDE Universal BIOS (XUB) on the XT-IDE card.  That BIOS interrogates the IDE drive (or CF) to determine the geometry of the IDE drive (or CF).  It does not use the C:/D: drive types stored in the SETUP (CMOS SETUP).


IBM 5170 (IBM AT) example #1 of 2 - MFM hard drive is faulty

In this example, the MFM hard drive attached to the 'IBM Fixed Disk and Diskette Drive Adapter' in my IBM 5170 has gone faulty, and I cannot find a suitable replacement MFM drive, and I want to use an XT-IDE card as a substitute for the drive.

I am leaving the 'IBM Fixed Disk and Diskette Drive Adapter' in place, because I need it to control the floppy drive.

STEP 1:  I decide to leave the faulty MFM hard drive in my IBM 5170, for the reason described at here.

STEP 2:  Because I have a type 1 motherboard, in order to use an XT-IDE card on the type 1 motherboard, I have to upgrade the IBM BIOS on the motherboard to the 06/10/85 dated IBM BIOS.  You can see that requirement in note 1 at here.  I do that upgrade.

STEP 3:  Due to the faulty MFM hard drive, the motherboard BIOS is still generating a 17xx error at start-up of my IBM 5170.  To get rid of that 17xx error, I run SETUP (see here) and set the C: drive type to 0 (zero).  Now, the motherboard BIOS no longer thinks that there is a MFM hard drive attached to the 'IBM Fixed Disk and Diskette Drive Adapter'.

STEP 4:  With power off, I plug in the XT-IDE card.

STEP 5:  I power on my IBM 5170, see the XTIDE Universal BIOS (XUB) appear on-screen, then watch as the XUB boots from the IDE drive (or CF) attached to my XT-IDE card.


IBM 5170 (IBM AT) example #2 of 2 - I want the IDE drive on the XT-IDE card to complement the existing MFM hard drive

In this example, I want the IDE drive (or CF) attached to my XT-IDE card to become the second hard drive in my IBM 5170.

Background: The version of the XTIDE Universal BIOS (XUB) that I have fitted to the XT-IDE card is V2.0.0 beta 3+

STEP 1:  Because I have a type 1 motherboard, in order to use an XT-IDE card on the type 1 motherboard, I have to upgrade the IBM BIOS on the motherboard to the 06/10/85 dated IBM BIOS.  You can see that requirement in note 1 at here.  I do that upgrade.

STEP 2:  With power off, I plug in the XT-IDE card.

STEP 3:  I power on my IBM 5170, see the XTIDE Universal BIOS (XUB) appear on-screen, then watch as the XUB boots from the MFM drive.

So, by default, the MFM drive is the first hard drive and the XT-IDE's drive is the second hard drive.  The IBM 5170 booted from the MFM drive (the first hard drive), with the MFM drive presented as logical drive C:, and the XT-IDE's drive presented as logical drive D:

If instead, I want to boot from the XT-IDE's drive, I would press the 'D' key when I see the Hotkeybar shown by XUB V2.0.0 beta 3+.  That will make the XT-IDE's drive be the first hard drive, and the MFM drive be the second hard drive.  As a result, the IBM 5170 will boot from the XT-IDE's drive (now, the first hard drive), with the XT-IDE's drive presented as logical drive C:, and the MFM drive presented as logical drive D:

Optionally, if I want the IBM 5170 to boot from the XT-IDE's drive by default (i.e. I don't need to press the 'D' key), I can do that by reconfiguring the XUB in the XT-IDE card, specifically, changing the 'Default boot drive' setting to 81 (eighty one).