What is memory protection and why is it so hard to implement for the AmigaOS?

[AlexC]

The funny thing is that Microsoft team had similar problem in Windows 3.x era and they did it solving all those problems. It's a common knowledge and in era of virtualization support in modern CPUs this should even not be discussed further but just be done. I can't imagine any commercial OS for home users or for business without MP today. I can think of some uses in embedded market without it and people are still using DOS today so in a long run you can live without it, but than you are filling niche in dying market.

[AlexC]

To be fair DOS virtualization is trivial compared to AmigaOS.

True. I don't compare DOS with AmigaOS but with Windows 3.x problem - mind you that they even had problem with different types of memory to solve which protected mode helped to fix. Anyway my point is that most of issues in term of theory has been solved already and this is strictly implementation problem in terms of producing code. There was a similar case in area of memory allocator when AmigaOS got it's own implementation of slab allocator and swap to make it more advance and efficient (which was a very wise move BTW).