[rescue] AS/400? Anyone?

Patrick Finnegan pat at computer-refuge.org
Fri Jan 18 01:02:30 CST 2008

On Friday 18 January 2008 01:44, Geoffrey S. Mendelson wrote:
> Bear in mind they don't emulate the AS/400 native instruction set. If
> you had a program written in it, you simply could not run it on
> anything except an old machine.

IBM went to great lengths to make sure that customers COULDN'T write 
anything native to the machine.

> What makes it dead and gone in my book is that the native instruction
> set, which at one time ran on a real computer is no longer supported
> on anything.

As I understand it, even the CISC AS/400 systems were not consistent in 
their "native" instruction language.  As well, the POWER(PC) based 
AS/400 I've got is called an "AS/400".

> Even if no one outside of the development labs could access the "bare
> metal", at one time it existed, someone could write programs for it
> and they did.

It would be no different than writing a program in microcode on a VAX.  
You program would run on an 11/780, but not an 11/750, etc.  The 
microcode "emulates" the VAX architecture in the same way that 
AS/400 "hardware abstraction" stuff "emulates" an AS/400.

Purdue University ITAP/RCAC       --- http://www.rcac.purdue.edu/
The Computer Refuge               --- http://computer-refuge.org

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