Harvard vs. vonNeuman ... was Re: Early computers was Re: Relay computers

From: Peter C. Wallace <pcw_at_mesanet.com>
Date: Mon Sep 27 17:57:20 2004

On Mon, 27 Sep 2004, Tom Jennings wrote:

> re: Zuse, and stored-program, etc...
> > On Sun, 2004-09-26 at 01:37, Hans B PUFAL wrote:
> > This web page also seems apropro :
> > http://irb.cs.tu-berlin.de/~zuse/Konrad_Zuse/Neumann_vs_Zuse.html
> First, I don't mean to disparage Zuse's accomplishments, especially
> under the circumstances he lived in, it's pretty amazing.
> The idea-of-the-century wasn't machines that calculate automatically,
> but machines-that-modify-themselves-as-part-of-normal-operation. Other
> than particular logical arrangement, I don't see how the Zuse machines
> are an architectural improvement over the IBM and Harvard relay
> calculators.
> In many ways it's an unfair comparison, the IBM machines had a nearly
> unlimited budget, and poor Konrad sat by himself in his living room
> punching programs into used 35mm film stock, never mind the war going on
> around him.
> Less well-known but historically more interesting is his 'planKalculus',
> his algorithmic nomenclature he worked up to describe computer
> programs. He even had chess-playing code! It's described in fair detail
> in A HIST. OF COMP. 20TH CENT. (1980, MIT press) by Knuth.
> (For the record, PICs are "Harvard architecture"; data and program
> memory are separate. "von Neumann architecture" is program and data
> stored in the same memory.)

Actually many modern CPU's with caches are Harvard Architecture, the
instruction streams and data streams only being mixed on the memory of the

I've also heard that machines that mix data and instruction streams are more
properly called "Princeton achitecture"...

Isn't self modifying code pretty much deprecated these days (aside from
trampolines and such)

Peter Wallace
Received on Mon Sep 27 2004 - 17:57:20 BST

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