I am using both IDE connectors on the motherboard.
I use one for the hard-drive and the other for the CDROM drive.
If I set the CDROM drive to Master the CDROM will not work when I boot off a boor disk with CDROM support.
So I have the CDROM set to “Cable select” which works fine when I boot off the DOS boot disk.
And I have the hard-drive set to “Master/Single drive” which is the same setting.
I have swapped out everything , even the power supply.
Cables, drives, motherboards, PSU.
And I have the same problem.
It does not make sense huh ?
How can I be running into the same problem ?
Unless, Maybe the DOS boot drive I am using has a virus or is causing the motherboard to disable the hard-drive when I boot of the DOS boot disks ?
But I have tried this boot disk in other computers and it works okay.
The motherboard drive auto-detect function discovers my hard-drive fine but just as a “Slave” drive.
No as a master ?
And the drive is disabled when ever I boot off a DOS boot disk to fdisk the drive.
So I get an error “No drives found “.

Intel486dx33 wrote:

How can I be running into the same problem ?

Consistently plugging the IDE cables into the motherboard with the connector back-to-front?

The ribbons I am using are like these.
The IDE ribbons only have two connectors. One for the hard-drive and one for the motherboard.
I have the RED wire side as pin-1 and next to power connector on drives.
The drives work fine. The cables are connected correctly.
The floppy drive works fine too.

I don’t understand why the motherboard discovers the hard-drive as a “slave” when I have the jumpers set for “master/single drive”.

Okay, I need new IDE ribbons. They are definitely the problem.