IBM PS/2 Model 50 (8550) September, 2018


PS/2 Model 50 - Part 2

After working on the PS/2 Model 50, I discovered that the hard drive was having issues. One thing I thought of was maybe the drive controller was the problem.

I grabbed one on eBay and noticed it looked a little different than mine, but it fit correctly and was recognized by the system.

Unfortunately, the controller wasn't the issue. With either of them, I got the same errors with the hard drive that I had.

I went back to eBay and looked for replacement hard drives. I was able to find some, but they all cost more than I paid for the entire system.

I decided to spend that money and grab the drive anyway. Turns out I bought a drive for a different PS/2 system, so I couldn't use it.

The seller let me return it and get my money back. I was then able to buy a drive that was actually compatible with this system.

I'll make this part short... every combination of drive/controller I used all gave me the same issue. I actually bought like 3 PS/2 hard drives, none worked.

I suppose you don't really need a hard drive to be able to use a computer. I have a working floppy drive, so I can just keep booting MS-DOS (or even IBM PC-DOS) from disks.

I don't want to give up on this system, but it was making me very frustrated. In order to take my mind off of the hard drive situation, I decided to do another upgrade.

I grabbed an Intel 80287 off eBay and instaled that into the slot on the motherboard. I don't know what software really uses this, but I thought it would be cool to add one.


After installing the Mountain card and its ADF file, I thought that would be all I'd need to get a hard drive working. Figured I could just connect the drive and boot up the system.

With the drive connected... nothing happened. Booting to DOS (from a floppy), there is no C: drive, and fdisk cannot see anything. Why is this happening? I'm pretty sure I connected everything right and I don't think I need a terminator or anything.

Searching around, I figured out what was wrong. It looks like this SCSI card is only for tape drives. The issue is that this card does not have a BIOS option ROM. That's what I need to be able to boot from a SCSI drive.

I wasn't sure if I could continue with the system. I could continue to just boot from a floppy disk, but I really wanted a hard drive. I was getting frustrated with all the hard drive solutions I've tried not working. I decided to make an eBay saved search for "MCA SCSI" and just left it alone.

I forget how long it took, but one day I got an email from eBay that my saved search had a match! I wasn't sure I really wanted to spend more money or time on this system, but I also just wanted to get it working. I tried my best to verify that this card had a BIOS Option ROM and would actually work here. It seemed like it did, so I bought this card, hoping it would finally solve my issues.

When the card arrived in the mail, there was a floppy disk included with the ADF file to enable the card in the system's BIOS. I installed the card, used the reference disk to load the ADF file and powered the machine back off to connect the hard drive to test.

For now, I am using a SCSI drive that seems to be from a Mac of some sort and an external molex supply. I'll figure out a power solution once I can confirm the card/drive works.

After connecting the drive and powering on the system, to my surprise a "Future Domain" screen appeared! That is the BIOS Option ROM running and detecting my hard drive!

Booting off of a floppy disk, and I was correctly able to run fdisk/format on the drive! Success! I finally had a drive controller that could read and boot off of drives!