Re: Kernel in userland

Matti Aarnio (matti.aarnio@sonera.fi)
Wed, 1 Dec 1999 16:19:57 +0200


On Wed, Dec 01, 1999 at 02:57:12PM +0100, Karel Kulhavy wrote:
> Hi
>
> I've heard a rumour that someone ported Linux Kernel so it can run as
> an user process under Unix. Where can I find it?

OSF-Institute (or whatever the name is) did something like
that a while ago. They ported Linux over MACH-kernel.

With MACH, kernel isn't a monolith, e.g. hard device IO can
be its own subserver which is called via RPC calls from other
(sub)servers. All of which are running outside the innermost
kernel protection ring.

Depending what the profets told you about MACH-like paradigms,
kernel services either are in "user process", or are somewhat
special case...

I recall they ran the resulting system on HP-PA hardware, and
did observe about 5-10 % performance penalty against then current
monolithic HP-UX.

Another change of doing things is VMWARE (www.vmware.com), which
allows you running arbitary (pretty much) guest operating systems
on top of i586+ virtualization facilities.
(You *can* run Linux at such virtual box, but usually it is used
to run e.g. some Windows in that box. Reminds me very much of
IBM VM/SP (Virtual Machine/System Product) at S/370 type hardware.)

> Karel Kulhavy

/Matti Aarnio <matti.aarnio@sonera.fi>

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