[rescue] AS/400? Anyone?

Jonathan C. Patschke jp at celestrion.net
Thu Jan 17 23:30:20 CST 2008

On Fri, 18 Jan 2008, Geoffrey S. Mendelson wrote:

>> They had AS/400 CPUs.  They were CISC CPUs based off the design of
>> the System/38 processors, but with a System/370-ish instruction set
>> (underneath the portability layer).
> That's an interesting question. If the POWER processors were extended to
> add the necesary instructions to run AS400 code, are they AS400's or
> RS6000's?

They're POWER architecture systems running POWER code.

AS/400 systems (under OS/400 anyway) do not run processor-native code.
They run code written against a 128-bit virtual machine architecture.
This virtual machine architecture was ported to POWER.

> Do they run OS400?


> Do they actually run the code natively or is it some form of hardware
> enhnaced emulation?

They run it as natively as the original AS/400s did.  The original
AS/400 systems were a 48-bit CISC system hardware-wise, but the VM was a
128-bit memory-mapped-everything architecture.  The new ones are a
64-bit RISC system running the same VM architecture.

Jonathan Patschke
Elgin, TX

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