Re: AS/400 History

John,

  Well that would be because the S/32 was a 16-bit register based
processor that was very similair (at least in concept) to the RISC
processors of today.  Because of this the S/32 was designed to run S/3
OS operations in microcode (albeit slowly).  (The S/34 and S/36 ran the
OS in a second processor that directly executed the instructions).  With
the advance in processor speed in the RISC chips it was reasoned that
going back to emulation would allow the entire S/36 OS to run on top of
SLIC while still going acceptably fast.  
  So there you have it.  OS/400's support for S/36 object code execution
is internally much more like the 'bionic desk' than the S/36 that
created the programs!
  
  The more things change, the more they stay the same....

  Larry Bolhuis
  Arbor Solutions, Inc
  lbolhui@ibm.net

John Carr wrote:
> 
> C'on yall
> 
> Trivia question:   Why was the Sys/32 architecture so
> important/instrumental to running the Sys/36 code on the AS/400 ???
> 
> This is a neat one.
> (BTW I graduated from High school in, dare I say it,  '71)
> 
> John Carr
> EdgeTech
> 
> -------------
> Sys/3    June 1969
> 
> (Late 69 Dr. Frank S. got a job assignment to design the architecture for
> the successor to the Sys/3.   Jan 8 '70 Frank makes presentation to Roch.
> to build a machine which would have single level store, High level
> machine interface, etc you know the rest <ie 20-30 years before NT>)
> 
> Sys/32    Jan   1975
> Sys/34   April  1977
> Sys/38   Oct.  24 1978  ** Red Letter Day **
> Sys/36   May    1983
> 
> "Late 1985 small group of developers demonstrated that the software for
> the Sys/36 could run on a Sys/38" (never, never the other way around BTW)
> 
> After a "Record" 28 month development cycle the AS/400 was announced on
> June 21 1988.
> 
> Lets see,  NT 5.0 won't be out for another 2 years, and thats just a new
> version,  Hmm,  I think Rochester did a more heroic job.
> 
> (As per "Inside the AS/400 by Dr. Frank Soltis)
> 
> Trivia question:   Why was the Sys/32 architecture so
> important/instrumental to running the Sys/36 code on the AS/400 ???
> 
> John Carr
> EdgeTech
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