UCSD PASCAL (P-system) P-code Was:(Why is it that ...)

From: ajp166 <ajp166_at_bellatlantic.net>
Date: Thu Nov 30 18:37:11 2000

From: Roger Ivie <rivie_at_teraglobal.com>


>That's an extremely interesting remark because of two of
>the rumors I heard about the WD P-engine:
>
>1) It failed because a Z80 could execute P-code faster
>2) It was a remicrocoded 11/03


Z80 was a good pcode engine, in 1978 the fast ones were 4mhz
and the PDP-11/03 in the guise of an H11 was a bit faster.

The WD Pascal microengine was the WD13 chipset as
was the LSI-11 and the S100 box (forgot the name). The uEngine
was a failure as WD was not a reliable vendor back then and
it was buggy. It did run the pcode fastest of the pack then.

The PDP-11 and to a lesser extent z80 had the addressing modes
and instuction set needed to build a good stack oriented engine.

UCSD was not so much a failure as the leading edge. With the
avilability of natively compiled languages that were faster or better
a P-code compiler was a weakness. The idea of cross platform
code portability in the form of a compiled HLL was a big winner
that remains.

Allison
Received on Thu Nov 30 2000 - 18:37:11 GMT