Re: Questions about copy-on-write

[Sam Mason]

Neal H. Walfield wrote:
>physmem holds mappings
>between virtual frame (per-task handles for physical memory blocks)
>and physical frames.

Is this where most of the memory protections stem from?  Tasks can't
ask for arbitrary pages of memory but they can ask physmem for a new
(otherwise unused) page of memory or they can ask for a specific page
of memory out of a container.

If that's true then I think my confusion was coming from a belief that
this mechanism was in L4 iself, rather then physmem.

I think the next challenge for me is to figure out how a task can
revoke a mapping it gave to another task.  I guess I'll have to give
the L4 a bit of a read. . .

Thanks,
  Sam