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From: guy@gorodish.UUCP
Newsgroups: comp.arch
Subject: Re: catering to bad code
Message-ID: <13608@sun.uucp>
Date: Thu, 19-Feb-87 03:01:17 EST
Article-I.D.: sun.13608
Posted: Thu Feb 19 03:01:17 1987
Date-Received: Fri, 20-Feb-87 07:01:34 EST
References: <14833@amdcad.UUCP> <13602@sun.uucp>
Sender: news@sun.uucp
Reply-To: guy@sun.UUCP (Guy Harris)
Organization: Sun Microsystems, Mountain View
Lines: 16

>It's not just an issue of porting to a Sun or other machine, it's an issue of
>relying on code to do something that it does only on a subset of machines.

It's even more than that.  Programs that try to use location 0
because they're trying to dereference null pointers do so because
they have *bugs* in them - the core dump is just a more emphatic way
of pointing this out than various flavors of maybe-correct behavior
are.  VAX/VMS takes location 0 out of the address space by default,
probably for just that reason.

I can understand the desire for expediency, but I very strongly
support Rob Warnock's desire that you *not* make this the default
behavior.  Even though some paging versions of S5, at least, permit
you to define images that will be run without location 0, it's *not*
the default; as a result, I've had to fix a number of bugs that
*they* should have fixed.