Newsgroups: comp.arch
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uupsi!ficc!peter
From: peter@ficc.ferranti.com (Peter da Silva)
Subject: Re: Segmented Architectures ( formerly Re: 48-bit computers)
Message-ID: <1PGAOP7@xds13.ferranti.com>
Organization: Xenix Support, FICC
References: <efeustel.669650766@tiger1> <1360009@aspen.IAG.HP.COM>
Date: Wed, 3 Apr 91 17:45:20 GMT

In article <1360009@aspen.IAG.HP.COM>, huck@aspen.IAG.HP.COM (Jerry Huck) writes:
> So for HP, segmentation was not a trade-off against flat addressing,
> but rather: is it useful to extend beyond the maximum flat addressing
> you can support in your general register file?

This is the exact same trade-off that Intel made in the 8086, just 10 years
or so down the road. It gives you a short-term paper advantage, but once
things get to the point where you really need those addressing bits people
will be using your name in vain.

> I think most of the arguments against segmentation assume you give up
> some flat addressing to get it.  That's not necessary.

But that's what you just described: you only have 32 bits of flat address
space in a 48 bit machine. 
-- 
Peter da Silva.  `-_-'  peter@ferranti.com
+1 713 274 5180.  'U`  "Have you hugged your wolf today?"
