Re: NetBSD without MMU ?

[woods%weird.com@localhost (Greg A. Woods)]

[ On , April 12, 2002 at 12:27:58 (-0400), Perry E. Metzger wrote: ]
> Subject: Re: NetBSD without MMU ?
>
> MINIX uses the x86 segment registers to much the same purpose as an
> MMU.

I don't know that I'd call the way MINIX uses the 8088 segment registers
as "base registers" really that much of an MMU-like function, though I
guess in comparison to something without any such feature (like maybe a
6502) it is a form of memory managment -- but it's not a separate MMU
(tightly or loosely coupled) -- its integrated into the programming
model of the main CPU.

> It is hard to do fork without any memory management at all.

Not really.  Even if all you do is "bank" swapping (perhaps with a
reloacting loader so you can have at least more than one process in main
memory at a time and thus get useful work done why the memory manager
does, er, waits for, the swapping I/Os).

(in fact I would say an MMU makes implementing fork "harder"! :-)

-- 
                                                                Greg A. Woods

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