Newsgroups: comp.arch
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: looking for >32-bit address space
Message-ID: <1989Apr12.031821.7517@utzoo.uucp>
Organization: U of Toronto Zoology
References: <1032@myrias.UUCP> <1989Apr3.164538.277@utzoo.uucp> <2516@scolex.sco.COM> <1989Apr7.194933.4861@utzoo.uucp> <2534@scolex.sco.COM>
Date: Wed, 12 Apr 89 03:18:21 GMT

In article <2534@scolex.sco.COM> seanf@scolex.UUCP (Sean Fagan) writes:
>>One can argue about the merits of breaking the
>>linear address space up into segments, but the point is that normal
>>pointer manipulation is not penalized in either efficiency or simplicity.
>
>Neither is it on the '386.

It will be when you start wanting more than 32 bits of address... which
is what started this whole line of discussion.  The 386 looks okay right
now because its segments (unlike those of the smaller Intel flakes, er
excuse me chips) are big enough that you can ignore the ability to
have more than one of them.

>>The real problem with >32 bit addresses is that avoiding the dreaded
>>Intel Pointer Syndrome requires a 64-bit word.  Which costs more than
>>a lot of people want to pay just now.
>
>I still maintain that segments are possible a Good Thing, although I don't
>like some implementations.

I agree that segments are possibly a good thing -- but the segment number
has to be part of a normal, ordinary pointer, not a tacked-on extra.
-- 
Welcome to Mars!  Your         |     Henry Spencer at U of Toronto Zoology
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