Is Plan9 has a microkernel architecture?

No, as far as I know...

It is a small kernel, though...

Cheers!

On 10/6/07, Andrew Wingorodov wrote:

I think the answer is in here:
http://en.wikipedia.org/wiki/Plan_9_from_Bell_Labs
But I think it's not.

with Plan 9 the adjective is more important than the compound noun,
so it's micro and modular, but not a `microkernel'.
most of the microkernels are (probably) much more
elaborate, and indeed simply much more.

in an apparently under-read paper, it was observed that:
The UNIX kernel is an I/O multiplexer more than
a complete operating system. This is as it should be.
Because of this outlook, many features are
found in most other operating systems that are missing
from the UNIX kernel.
Plan 9 goes further, removing even the storage subsystems
from the kernel, and making it a name-space multiplexor,
as much as (or more than) an IO multiplexor, with its focus
on a single protocol.

Charles Forsyth terzarima.net> wrote:

that sounds great, but oses has not only storage subsystems
you mean, the all 9 subsystems works through 9P and filesystems,
that safe for kernel? a new filesystem engine is not needed
include into the kernel?

my new little experience with QNX made me a fan of microkernel :)
Plan 9 is very good, very nice job, next and future of IT, respect.
No superusers! Infinite File System! Unified interface off all,
any more, of course a big deal...
But "Can We Make OSes Reliable and Secure" by A.T. expresses
a good (maybe not fresh) ideas, isnt it?

the kernel doesn't actually implement all that much, and most complex things
are outside the kernel. the biggest exceptions are networking
and low-level device drivers, but the interface to those is small,
or even tiny. the device drivers aren't that big either.
the network has been in and out of the kernel at different times over the years.

qnx is probably the most reasonable so-called microkernel i've seen described
(but i haven't seen their code).

On 10/6/07, Charles Forsyth terzarima.net> wrote:

It's "open sourced" now, as of a few weeks ago.

Ever looked at the L4 family of microkernels?

On 10/7/07, David Leimbach gmail.com> wrote:

yep, I could never get them to build on red hat. My mistake, using red
hat, but ... long story.

ron

TUD:OS is pretty neat. I'd like to take Nemesis out for a spin as well, but
I've not the time now.

On 10/7/07, David Leimbach gmail.com> wrote:

after looking at the code, i didn't try to compile it.
the version i looked at was c++ and seemed much more
complicated than the claimed handful of system calls.

- erik