[Info-vax] RealWorldTech on Poulson

[glen herrmannsfeldt]

Neil Rieck <n.rieck at sympatico.ca> wrote:

(snip)
> Personal Comment: We all know that CISC architectures were too
> complicated to allow further development of computer technology. Then
> researchers at IBM came up with RISC which allowed the development of
> super scalar technologies like OOE. 

OOE goes back at least to the IBM 360/91 in about 1967.

The 360/91 was a favorite example in parallel computer architecture
books for many years.  Out of order, register renaming (S/360 only
has four floating point registers), imprecise interrupts, go at
least that far back.  (I don't know the CDC machines as well, but
they did many tricks, too.)

> (many industry people, including
> me, though the shift from CISC to RISC might be a mistake; but
> academics looking at yearly progress charts (smaller, cheaper, faster)
> in both memory and CPUs had the correct view. We've all seen the
> instruction complexity chart showing "CISC on the left, EPIC in the
> middle, and RISC on the right". Once HP engineers saw the speed-up
> going from CISC to RISC (due to instruction simplicity) then how did
> they ever think a mid point like EPIC would ever be as fast as RISC?

-- glen