Xah Lee's Unixism

[Pascal Bourguignon]

"Karl A. Krueger" <kkrueger at example.edu> writes:

> In comp.lang.lisp Pascal Bourguignon <spam at mouse-potato.com> wrote:
> > "John Thingstad" <john.thingstad at chello.no> writes:
> >> Note the Mac OS 10 / Darwin uses a unix kernel because of all the
> >> problems  with interoperabillity OS 9 had with talking to Windows and
> >> Unix boxes.
> > 
> > No that's not the reason. The reason is ONLY because of the lack of
> > virtual memory management (with separation of addressing spaces for
> > processes) in MacOS.
> 
> It was my impression that the Motorola 68000 CPU, upon which the
> original Macintosh was based, did not support memory management in
> hardware.  At least, that's usually given as the reason that portable
> Unix systems such as NetBSD will "never" run on the earlier 68k (or,
> for that matter, 8086 or 80286) chips.

That's not exactly true.  There are some small problems with the
instruction set, but at the time Motorola sold 68000, they sold PMMU
and SMMU (segmented MMU) for it, and there was 68000 based
unix workstations.

Actually, the segmented MMU would have been a perfect match to the
Memory Management of the MacOS. 

The problem was that they started with a 6809 and 64KB in mind for the
Macintosh...

-- 
__Pascal Bourguignon__                     http://www.informatimago.com/

Our enemies are innovative and resourceful, and so are we. They never
stop thinking about new ways to harm our country and our people, and
neither do we.