On Tue, 25 Oct 2011 22:32:44 +0100, Tim Streater wrote:
Well that's not surprising.. it wasn't until the 68030 series came out
that there was a working MMU to run the protection and coincidently
support paging and VM.
That is true for Motorola CPUs as used by Apple.

Mmmm no (again). The 030 was the first in the 68k line to have an
*on-board* MMU. You could perfectly well use a 68020 and use the 68851
MMU as a co-processor with it.

ISTR there being an MMU available for the '010, too, although it was a
bit clunky (and some vendors - e.g. Sun - implemented their own).

Several vendors implemented a kind of "elegant kludge" to do virtual
memory on the humble 68000, too (which lacked the necessary to implement
virtual memory properly) - that involved actually running two CPUs out of
phase with each other.

cheers

Jules