The road to Zettalinux

That was Intel. I used 50-series which also had segmented memory, and while I know far less about the silicon internals, I gather it worked very well.

It didn't migrate very well to Intel, and quite possibly because their segmentation was (compared to 50-series) broken.

I know it was used for security, for separating the OS from user-space, and from separating users/processes from each other.

Cheers,
Wol