[ECOS] Re: Memory protection

[Chris Waters]

>The question here is exactly what you want memory protection for?
>The current eCos system is oriented towards multi-threaded
>applications rather than multitasking.

I was thinking more about protecting the OS from errant user code. When user
code is run-time downloadable there is a danger that it won't be as well
tested as the kernel.

I haven't really given much thought to the practical difficulties of doing
this. You mention the overhead when making system calls. Is this because the
MMU mappings need to be replaced with the system mappings when control
passes to the OS and back to the user mappings when it switches back to user
code?

Chris.