[comp.sys.mac.hardware] PMMU under pre-7.0 Systems

rosen@cs.utexas.edu (Eric Carl Rosen) (12/12/90)

I know that System 7.0, A/UX, and Virtual (and related products) use the
M68851 memory managment unit, but does the generic 6.x Macintosh O/S use
the capabilities of the PMMU in any way? If so, how?

--Eric

russotto@eng.umd.edu (Matthew T. Russotto) (12/13/90)

In article <1024@priddy.cs.utexas.edu> rosen@cs.utexas.edu (Eric Carl Rosen) writes:
>I know that System 7.0, A/UX, and Virtual (and related products) use the
>M68851 memory managment unit, but does the generic 6.x Macintosh O/S use
>the capabilities of the PMMU in any way? If so, how?

Yes and no-- yes, they use it to mask off the top 8 bits of the address in
24-bit mode.  No, this is not any more than the HMMU that is standard with
the mac II can do.


--
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
     .sig under construction, like the rest of this campus.