User avatar
intric8
Seattle, WA, USA

Posted Sun Jan 29, 2023 8:57 pm

This was a bit of a brain teaser, but after thinking it through step by step I finally figured it out.

I'd read that Commodore 8-bit machines could handle up to eight individual drives. I was worried it might be four since most of the drives I've ever encountered had DIP switches for 8-11. But I breathed a sigh of relief when I saw the number was much higher than I expected. (In fact, I think you actually can go beyond 8 drives but you'd have to do quite a delicate dance that isn't very practical to make the whole thing work...)

What I wanted was a setup of the following:
  • C128D with internal 1571 (set to 8)
  • CMD RAMLink (default 16)
  • MSD SD-2 5.25 dual drive (set to 9)
  • CMD HD (default 12)
  • Commodore 1581 3.5" drive (set to 10)
In addition to all of this, last month I sourced a rather difficult high-speed parallel cable to find for the CMD RAMLink to connect to the CMD HDD. The hard drive is a ridiculous 2GB!

The way I could use it was by attaching the CMD HDD to my RAMLink's parallel port.

I'd tried that at the end of 2022 and was pretty blown away by the transfer speeds.

This weekend, I decided to put together the whole shebang. But I kept running into this really weird problem: the 1581 (which was originally at the end of the wiring chain) wouldn't read disks. No matter where I put it in the chain I would get the same result. That kind of sick feeling started to drop in my stomach wondering if the drive mechanism had suddenly just decided to die out of nowhere.

I grabbed another 1581 off the shelf and tried again. Same result!

Now I knew I had a conflict somewhere.

After a lot of trial and error I finally walked away from the project and took a break. After a few hours, it dawned on me to try one last thing.

I'd been attaching IEC devices to the CMD HDD that was connected via parallel cable. Instead, I decided to bypass it completely - essentially having it be an island in the chain since it was connected via parallel.

Like this:
Screenshot 2023-01-29 at 7.47.16 PM.png
Diagram by moi.


Once I did that, the 1581 sprang to life! And now I've got this amazingly insane Tower of Power. :commodore: <3
IMG_1385.jpg
Technically my MSD SD-2 is 2 drives, but it gets counted as 1 since it gets broken into 9:0 and 9:1. So, I guess I could say I have 6 drives right now, but not from an ID# perspective.


User avatar
McTrinsic

Posted Sun Jan 29, 2023 10:18 pm

Impressive setup, awesome.

I really like to find out where the the limits are with the old hardware and time and again I am positively surprised what’s possible.

And I learned something new: LUNs on IEC devices, cool!

Any software issues you encounter where the programs from back then can’t cope with this power-setup?

User avatar
intric8
Seattle, WA, USA

Posted Sun Jan 29, 2023 11:10 pm

Any software issues you encounter where the programs from back then can’t cope with this power-setup?
I've not seen anything yet. Some software likely is wired for 8-only, and sometimes to look for a 9. It's the productivity stuff and large file management that seems to not care at all how many drives you have - which is a good thing. =)





Return to “Commodore 8 Bits”