Linus Torvalds (torvalds@osdl.org) on 5/15/06 wrote:
---------------------------
>mas (mas769@hotmail.com) on 5/15/06 wrote:
>>
>>Don't know if you saw Tanenbaum's latest defence of
>>microkernels but here it is if not.
>
>I think he - and even more so Shapiro - kind of end up
>discussing past the point.
>
>Claiming that "embedded" OS's are secure, for example,
>is laughable. The whole point of an embedded system is
>that it doesn't even allow (much less support) the
>huge majority of things that make security hard.
>
>Shapiro (and to some degree Tanenbaum) also makes the
>mistake of equating different address spaces with the
>notion of modularity. They have nothing to do with each
>other. You can be modular without using hardware to enforce
>it, and you can generate a horribly messy system where
>two processes are intimately aware of how each other works
>even if they are separated by MMU boundaries.


So how do you feel about microkernel-ish single address space systems? Obviously the two are separate concepts, but it's always struck me that they'd work well together. You get lot's of little protection domains, but still allow easy sharing when needed.

Obviously this is a somewhat theoretical question since most current hardware has, at best, mediocre support for SAS systems.