On Fri, 14 Jul 2000, �iogo Sperb Schneider wrote:
> > How could you avoid programs to access memory areas
> > that don't belong to
> > them if your MMU is implemented in software? How
> > could you stop user
> > programs to overwrite the MMU code and make it work
> > as the user want?
>
> I thought the kernel used to control the
> communication between software and hardware. It could
> be implemented with semaphores.
No, you can't. That's nosense. Please read "Operating systems: design and
implementation" by Andrew Tanenbaum to understand what we're talking
about.
> > Low-level kernel routines, such as the MMU and
> > low-level scheduler code is
> > written in assembler, even in your beloved Linux.
>
> Not according to the documentation. By now only LILO
> still uses non-"C" code according to the docs.
Take a look at the files in /usr/src/linux/arch/i386 and see for yourself.
> Applications have access to what the kernel give
> access to, thus, you get the picture.
That's right in a system where the processor has some type of protection
levels. That's not the case of the Z80 family.
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