[Ilugc] Re: Minix
- From: siva@xxxxxxxxxxx (Sivasankar Chander)
- Date: Fri Sep 10 20:09:44 2004
I think Minix 1.0 should also be a microkernel (atleast from the architect's
perspective). Of course, 8088 does not support multiple privilege levels (or
rings). But the sources (protect.h) contain code to determine processor
type (8088, 286, 386, 486, so on) to make use of privilege levels if they
are available in order to run other subsystems (net, fs, ...) on lower level
privilege levels (TASK_PRIVILEGE or USER_PRIVILEGE).
Thanks for the info - that's probably how it installed and ran on both
an XT and an AT. It was exceptionally fast on an 8 MHz AT, but of course
there was no paging and both code and data were limited to 64k/process.
I never delved deep into the Minix source, but I should have :-(
Ofcourse, what Minix seriously lacked was virtual memory support (which was
the primary reason for Linus to fork off his own project). I also remember
another unofficial spin-off project by Kees J. Bot called Minix-vmd that
implemented virtual memory support on Minix 2.0.
The trouble was, there was no easy way to merge the patchsets (and there
were many, in addition to the VM) into Tanenbaum's codebase to get a new
and improved version. That's one of the reasons Linux took off the way
it did (in addition to the GPL).
But I do recollect that Minix was stabler and more reliable than Linux
for a long while, probably at least until Linux-1.0.9.
-Siva
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