I've been unable to work on PZ1 for some time, but now I'm active again.

My latest experiment is to add io-protection, where only kernel code can access the io-area. This will make it harder (impossible?) for user processes to crash other processes. Of course it costs some cpu cycles to do kernel calls instead of using direct io, but I felt it was interesting to see what hardware is needed and how much overhead there is.

I have just gotten the first working implementation running, where basic starts and can do normal stuff, but pokes directly to the io-area does nothing. WOHOO!