Path: utzoo!attcan!uunet!mcvax!ukc!warwick!cvaxa!aledm
From: aledm@cvaxa.sussex.ac.uk (Aled Morris)
Newsgroups: comp.unix.wizards
Subject: Re: Unix optimized for SPARC?
Summary: Not optimized, but "tailored"
Message-ID: <495@cvaxa.sussex.ac.uk>
Date: 11 Jul 88 15:33:14 GMT
References: <253@iconsys.UUCP>
Organization: School of Cognitive Sciences, Univ of Sussex, Brighton, UK
Lines: 34

In article <253@iconsys.UUCP>, ron@iconsys.UUCP (Ron Holt) writes:
> Recently, there has been fear expressed that evil AT&T and Sun will
> some how optimize future versions of Unix for SPARC.  Considering the
> portability of Unix being one of its best known traits, wouldn't this
> be rather difficult to do?  I wouldn't consider BSD optimized for the
> VAX nor SVR3 optimized for the 3B2 even though these machines were
> used as the porting bases for their respective Unix variants.  Of course,
> there are very machine specific sections of the Unix kernel, the VM code
> being a good example, but other than that, how could Unix be optimized
> for SPARC?

I'm not worried about an evil plot, but have you thought about the hardware
(implementation) dependencies that get wired into systems without anyone
noticing?

In a way, BSD *is* optimised for a Vax, since there is lots of code that
has hardwired in a dependency on the dereference of the address zero
returning zero, that pointers and ints are interchangaeable, etc. etc.
[NO FLAMES PLEASE...]  Likewise, when writing for the SPARC I would
keep my procedure argument lists to <= 6 args, so they'll all fit into
the register window, etc. etc. [I CAN HEAR YOU ALL GROANING ALREADY]

It takes a mammoth effort to write code which is truly portable,
and I don't mean just the machine-specific bits.  If AT&T write code
for the SPARC, expect to see SPARC-isms wired in.   THIS IS NOT GOOD.

Aled Morris
systems programmer

      mail: aledm@cvaxa.sussex.ac.uk   |   School of Cognitive Science
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