Processes and Communication (2)

[Peter Mueller]

> =>What is the advantage of having no kernel as opposed to a micro-kernel?
> =>Sounds as if someone said "micro-kernels are better then typical bloated
> =>kernels hence having no kernel must be better still" :-)
> 
>    Well, you'd have to agree that it is a radical idea, and there will
> always be young upstarts like myself that will jump at anything that
> goes against the establishment. :-) I think the basic idea it that if
> you can build a system that is quick and efficient without a kernel,
> then you'll end up with a more flexible system if you get rid of it.
> It also logically separates the different parts of the kernel
> (scheduler, memory manager, communications, etc.) into manageble and
> easily replaceable chunks, just like microkernels do for higher-level
> services.  However, keep in mind that it isn't even unanimously agreed
> upon that microkernels are the way to go, much less non-kernels.
> 

The microkernel came up, when OS researchers ask, what to do *not* into
the OS's kernel. They declare the kernel to be "small", thus micro, in comparison
with older OS's such as UNIX. (But: If you have a look into Mach kernel, which
is declared as a microkernel, you will shake your head. I've heard of 30000 lines of 
code (no comments). Is this really micro?) Well, actually there's a trend from
monolithic to microkernel based systems.

In distributed OS there's a real reason to provide a very small (nano-) kernel.
As there are many nodes which must run at least the kernel a big and heavy one
isn't useful. Too much overhead (especially on those multiprocessor systems). The
system must be highly flexible and the kernel small. (In PEACE the kernel is about
3000 lines of code big. And that's all, which must run on a node! All other 
things are added only when they're needed. The authors say: The kernel must provide
process execution and fast IPC. That's all. No scheduling, no memory management,
no protection. ... and it works.)

In our project, the microkernel will provide a very dynamic OS in terms like,
adaptability, scalability and others. It will give us the possibility to create
an OS as needed.

>                                         Gary Duzan
>                                         Time  Lord
>                                     Third Regeneration
>                          Humble Practitioner of the Computer Arts
> 
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