MACH and XWindows on Mac

[Eric Johnson]

In article <7009 at thorin.cs.unc.edu>, markham at tsc.cs.unc.edu (Andrew Markham) writes:
> This summer I may work with a project in which a fully developed system is
> ported over to the Mac from a Sun running 4.3 BSD with XWindows.  The problem
> is, since A/UX is System V with BSD extensions, there could be a lot more
> work in store for us than if we could get a hold of a 4.3 BSD compatible OS.
> 
> A long time ago (in a distant galaxy), I heard that there was a possibility
> of the MACH OS being ported to the Mac and I was wondering if anyone knows this
> for a fact and if so, are there any dates regarding its release?  Also, I
> assume that XWindows would also be made available for MACH.  Well, you get 
> the main idea.  If you have any information regarding the above, please 
> respond via e-mail or post to comp.sys.mac.
> 
> Thanks for any and all help provided,
> 
> Andy Markham
> <markham at sunmail.cs.unc.edu>
> Computer Science Department
> University of North Carolina at Chapel Hill


While A/UX is System V, it does have BSD extensions, especially in the
area of networking and inter-process communication.  In fact, it looks
like all networking under A/UX is Berkeley-oriented.  Apple even calls the
package B-NET for Berkeley Networking.

It may be easier to run A/UX and port the Berkeley-isms than trying a new
operating system (with probably less Tech support than Apple can
provide on A/UX).  I have found that by writing portable (or semi-portable)
code, I have little hassle porting code from System V to BSD
implementations, such as HP-UX (System V with BSD enhancements) to
SunOS (BSD) and back again.

Since you will be porting anyway, you may want to go through the
code and look for gotchas--BSD-oriented or otherwise.  If you are starting
from a Sun-3 (MC 68020 processor) you probably shouldn't have byte-ordering
problems.  Other funnies involve hidden padding in structures (always pad
structures yourself to at least 16-bit boundaries, if not 32-bit boundaries),
and representation dependencies (e.g., assuming that all ints and longs
are both 32 bits, etc.). Also check routines that get the time and the
strchr/rindex stuff.

By the way, X 11 runs under A/UX.

While not always fun, porting code can often improve the product
as hidden errors are found and the code is cleaned up to make it
more portable.

Anyway, take another look at A/UX, it might not be as hard as you think.

Have fun,
-Eric


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