AS/400 9404 and TWINAX questions...

From: Don Hills <>
Date: Wed Sep 29 05:51:21 2004

Ron Hudson <> wrote:
>In one of my jobs I worked for the communications product div of Novell,
>they were trying to port netware to the AS400, but the simulated machine the
>AS400 presents was not effiecient for Novell, they could not get the server
>to run well enough, And IBM would not release the actual machine instruction
>set so the server could be written at the lower level (AS400 machines all
>run a simulator of an imaginary machine.. They do this so that all models of
>the AS400 are binary-compatible.)

The actual machine instruction set was available for the System/38 (AS/400
predecessor). It was sufficiently baroque that no-one wrote anything for it
so they didn't bother publishing it for the AS/400 where, as you say, they
wanted to use different processor architectures within the range. That's not
to say it was badly designed, it was simply highly optimised for its role as
an OO database engine. There's a very interesting book about the AS/400's
design process written by the chief architect, Frank Solti: "Inside the
AS/400" ISBN 1-882419-66-9

>I think the imaginary machine's instruction set was called "MI" for Machine


Don Hills    (dmhills at attglobaldotnet)     Wellington, New Zealand
It's ironic that people who are too smart to engage in politics
are governed by people who are not as smart.
Received on Wed Sep 29 2004 - 05:51:21 BST

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