RIM Blackberry OS chose UNIX like QNX not Linux?
Posted: Wed 02 May 2012, 09:49
That's what's known as a microkernel.
Minix, L4, and the GNU Hurd (the OS originally known as GNU) are all microkernel-based.
The problem is that passing messages and similar tasks end up taking a bit of time, so you get a real performance hit. Prof. Andrew Tanenbaum (AST, the fellow who wrote Minix) said (~1992) that Linux was obsolete because it used a monolithic kernel, while Torvalds said that no-one had ever gotten good performance out of a microkernel. There was quite a flame war...
Linux is pretty well tied to the monolithic kernel model. None of the microkernels are anywhere near as far along--GNU has yet to make a release (even pre-alpha), though it was "in progress" during the 80s, Minix is at 3.x.x, but last I checked it didn't have USB support...L4 is just a kernel, no OS; it was the first formally verified non-trivial software, but that's the kernel without even the servers.
