[rescue] AS/400? Anyone?
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.
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