25 Apr
2018
25 Apr
'18
4:33 p.m.
On 2018-04-25 08:18, Ronald Natalie wrote:
The fun argument is what is Virtual Memory.
Typically, people align
that with paging but you can stretch the definition to cover paging.
This was a point of contention in the early VAX Unix days as the ATT
(System III, even V?) didn’t support paging on the VAX where as BSD
did. Our comment was that “It ain’t VIRTUAL memory if it isn’t all
there” as opposed to virtual addressing.
What about overlays? Virtual or not?
The main difference may be where the code lives which brings non-present
address space back into directly addressable state: in the kernel (and
where: in an interrupt handler or higher up) or in userspace.
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