Anyone who knows rare add-ons for , can you point me to the manual for this? It's a Mountain Computer part number 05-04031-02 that came in a HDD-less IBM 5160 (PC-XT) I rescued. I can't tell if it's an MFM, RLL, or ESDI controller or what the jumpers do.

And I know it's a hard drive controller of some sort, because Mountain Computer sold it for the PC & XT (5150 & 5160) at the same time they sold hard drive kits for Apple IIs.

Omni Complete Catalog of Computer Hardware and Accessories 1984, pp. 242-243: archive.org/details/Omni_Compl

But the only Mountain Computer manuals I can find are for their Apple II products. None for their IBM PC controller cards.

The Diagnostics disk from the XT's Guide to Operations recognizes that a controller is present & jumpered for a single HDD, but it doesn't say what the controller is or what kind it is.

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I have IBM DOS 2.1 for the PC-XT & IBM DOS 3.3 on disks the XT likes, but they don't have a setup program. The disks were installed before being shrink-wrapped.

The only other utilities I have are DEBUG & FDISK. None of the Debug commands worked, & FDisk simply says no HDD.

What I tried so far:
> debug
-> G=C800:5
-> G=C800:800
-> G=C800:CCC
-> G=C800:5
-> G=C800:6

What I haven't tried yet:
> SpeedStor minuszerodegrees.net/software/
> Other debug commands jeffpar.github.io/kbarchive/kb

There's no HDD attached. I have to figure out what the controller is & supports before sourcing a disk.

SpeedStor detected the controller but told me absolutely nothing about it. The other debug commands didn't work. But this one did:

A>debug
-g=c800:6
1701-B

"G=C800:6" printed the POST error code. Matches Scientific Micro Systems, OMTI, & Adaptec?

I still don't have any idea what basic kind of HDD to pair this mystery controller up with. & folks, any help is appreciated.

@arielmt Are you open to my own experiences doing something similar so you can maybe apply it to your situation :P?

@arielmt IBM DOS 2.1 and 3.3 don't have a setup program. You're expected to
"SYS C:" and copy the files.

But if FDISK can't see the hard drive, you need to low-level format a hard disk attached to it.

To low-level format, try one of these:

* Run SPEEDSTOR.
* Use an IBM PC Advanced Diagnostics diskette.
* Running DEBUG.COM then typing "g =c800:5" and a newline can _sometimes_ work. I wouldn't try it for this controller.

@cr1901 I already did try the Debug command, and it hung identically to commands for other controllers.

My problem is that I have to identify the controller type and jumper settings positively before I can source a hard drive to pair it with.

@arielmt SPEEDSTOR can be found here:

minuszerodegrees.net/software/

SPEEDSTOR might be able to tell you the drive geometry that the controller expects even WITHOUT a drive attached.

I've never tried SPEEDSTOR without a drive attached though, I just know that the hard drive controller has to "know" what geometry it supports without the hard disk attached (somewhere in the EPROMs).

@arielmt If the controller says it supports 17 sectors per track, it's MFM. 26 is RLL. Idk what ESDI does tho- same connector, different signals :(?

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