Ex-Microsoftie: Free Software Will Kill Redmond (ComputerWorld)

Linux will *always* kick ass over microkernels on x86. I've used Primes, which had a very fast ring-switching architecture. That WAS a micro-kernel (of sorts) - a lot of the OS that was user support ran in ring 2.

x86 can't ring-switch to save its life. They were planning to implement Primos on x86, but that's what killed it :-( the lack of fast switching.

Linux is a macrokernel that thinks it's a mcirokernel (linux is modular, that's a microkernel design). Everything is compiled into one "monolithic" lump that runs in ring 0 - that's a macrokernel.

Ring switching would cripple x86 performance if all the modules were pushed out of ring 0. The Prime 50-series could ring-switch at the same speed as a non-switch call. Unix only uses two rings (by design, and linux is the same because it would be a nightmare to change). Primos ran the microkernel in ring 0, a lot of user-support in ring 2, and left ring 3 to user-space code (can't remember what it did with ring 1 :-)

Oh, and like Unix, Primos was a Multics derivative :-)

Cheers,
Wol