For aesthetic reasons, I would prefer to run a US-english variant of System 6.0.8, but all my keyboards are of a Scandinavian layout. Is it possible to swap key maps (using ResEdit?) to use my Finnish layout keyboard on an US-english operating system variant?
Normally I'd be fine with just using an US layout, but on these early Mac keyboards, they did something really weird to accommodate the international layout - The entire bottom row of characters is shifted to the right by one, for example.
Yes. I hauled out my Mac Plus, with System 6.0.8, and tested this. The system file comes with two KMAP resources, which define the keyboard mapping. The Keyboard section of the control panel allows you to choose between these two keymaps, Domestic and International.
You are correct that the scancodes for the bottom row of the International keyboard are shifted by one key. This can be seen from Inside Macintosh volume III, chapter 2, figure 9:
Make a copy of your System file, and open that copy in ResEdit. Edit the KMAP resource named International to your desired layout. Replace the System file with your new copy, and reboot. Et voila!
KMAPs here. Both my system files have 3 KMAPs with IDs 0, 2 and 5. Their contents appear identical. I figured I might be able to copy my intl. keymap from my Finnish variant to the english one, but it may not be that simple? I'm using ResEdit 2.1.3 if that makes any difference.
KCHR resource of the System file. That one contains the different keymaps I was looking for.