[rescue] AS/400? Anyone?

Jonathan C. Patschke jp at celestrion.net
Fri Jan 18 10:32:58 CST 2008

On Fri, 18 Jan 2008, 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.

Nobody wrote anything against the AS/400 native instruction set besides
the TIMI firmware/microcode.

> You could not, as I understand it, boot the native AS/400 version of
> the virtual machine on a POWER computer, you can only run the
> emulation of the virtual computer it emulated.

You're misunderstanding.  The virtual machine is -part of the
architecture specification-.  Just like how no modern x86 CPU implements
the x86 instruction set in hardware anymore.  That doesn't make an Intel
Core 2 CPU non-x86; it just means that nobody besides Intel writes
native machine code.  AS/400 is the same way, except it was born that
way; it just had a more abstract idea of what the microcode is supposed
to implement.

You can run S/38 code on an i5, and it will take no more of an indirect
path to execution than it did on the black (RS64, non-RS/6000) AS/400 in
my workroom or the white AS/400 holding up my TV.  The same goes for
AS/400-specific applications.

> 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.
> 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.

x86 is also dead and gone, then.  Whee!  Hell, POWER is dead and gone,
also as there are parts of it that went to live in microcode forever
after the PPC architecture merger.  For that matter, the VAX -NEVER

Jonathan Patschke
Elgin, TX

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