Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!wuarchive!uunet!cbmvax!valentin
From: valentin@cbmvax.commodore.com (Valentin Pepelea)
Newsgroups: comp.sys.amiga.tech
Subject: Re: MMU + A3000 + AmigaOS2.0 == Non-crashing system?
Message-ID: <13716@cbmvax.commodore.com>
Date: 9 Aug 90 03:51:21 GMT
References: <2489@clinet.FI> <20889@grebyn.com> <6405@wolfen.cc.uow.oz> <20927@grebyn.com> <13625@cbmvax.commodore.com> <6315@sugar.hackercorp.com>
Reply-To: valentin@cbmvax (Valentin Pepelea)
Organization: Commodore, West Chester, PA
Lines: 37

In article <6315@sugar.hackercorp.com> peter@sugar.hackercorp.com
(Peter da Silva) writes:
>
>> It is very difficult to convince a programmer that a global addressing space
>> is much more efficient and versatile than a separate addressing spaces as
>> implemented in Unix.
>
> To a certain point, this is true. Eventually, though, you run out of address
> bits. In the 16 bit world this has led to Split I/D segments and then segment
> registers. In the 32-bit world it's just starting to happen. Time for a 64
> bit address space?
>
> (see comp.arch for more info)

Bad example. The comp.arch example involves a data file that contains so much
information, it is overflowing the the 4,300 Meg limit of IBM's VSAM. Virtual
storage and virtual memory are two different concepts. And in the IBM world,
where a file is not a stream of characters, and where an ASCII character
just isn't, we cannot even compare the two.

Now  it's my turn to give a really bad example. "This planet is too small for
the two of us. Proof? I can hop into a space shuttle and blast away from
earth."

Indeed the 4 Gig address space offered by the 680x0 family could be overflowed
if a programmer really wanted to. But then I could write a program right now
which would overflow the address space of a 64-bit computer. Whether a
programmer chooses to be smart and not need so much memory, whether he chooses
to develop under an operating system that offers separate address spaces, or
whether he chooses to divide his program into overlays is irrelevant.

Valentin
-- 
The Goddess of democracy? "The tyrants     Name:    Valentin Pepelea
may distroy a statue,  but they cannot     Phone:   (215) 431-9327
kill a god."                               UseNet:  cbmvax!valentin@uunet.uu.net
             - Ancient Chinese Proverb     Claimer: I not Commodore spokesman be