Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!usc!apple!apple.com!chewy
From: chewy@apple.com (Paul Snively)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Why not Mach as version 8.0
Message-ID: <7100@goofy.Apple.COM>
Date: 9 Mar 90 20:31:02 GMT
Sender: usenet@Apple.COM
Organization: Apple Computer, Inc.
Lines: 45
References:<39127@apple.Apple.COM> <1236@swbatl.sbc.com>

In article <1236@swbatl.sbc.com> gilstrap@swbatl.sbc.com (3929) writes:
> why not use an
> implementation of Mach as verrsion 8.0 of the MacOS?  It would seem that 
you
> could preserve the shared memory areas via Mach's shared virtual memory 
through
> VM inheritance (e.g. don't copy-on-write but inherit a shared chunk of 
VM).
> This would allow the large majority of Mac programs which do twiddly 
things
> in the system heap and such to still run correctly.
> 
> I guess I'm interested in hearing what the problems are (I'm sure there 
are
> at least a few).

Mmmm, yeah.  Emulating the Mac toolbox and OS would be one, although it's 
already been done for A/UX.  I'm not exactly sure how 
architecturally-specific that would be.

Another would be size and installation.  What do you do about non-MMU (non 
'020/851 and '030) machines?

What about responsiveness?  We'd like to stay more responsive than either 
a NeXT or a Sun. ;-)

There'd also be an identity problem: is it UNIX, or is it MacOS?  At least 
with A/UX you know what you're getting yourself into.  We'd also have to 
deal with the same compatibility headaches as we do with A/UX.

As UNIX kernels go, I really like MACH, but I wouldn't try to foist it off 
as the Macintosh Operating System.

__________________________________________________________________________
                                Paul Snively
                      Macintosh Developer Technical Support
                             Apple Computer, Inc.

1st Choice: Paul_Snively.DTS@qm.gateway.apple.com
2nd Choice: CHEWBACCA@applelink.apple.com
Last Choice: chewy@apple.com

Just because I work for Apple Computer, Inc. doesn't mean that I believe 
what they believe, or vice-versa.
__________________________________________________________________________