28 May
1997
28 May
'97
1:49 a.m.
[p-code, etc]
It was to be a machine-independent interpreted
pseudo-machine code
(hmmm...), much
the same as Java is today. I remember versions of the P-code
intepreter for IBM-PC and Apple II, as well as TI. (There were also
versions for non-consumer machines such as Teraks)
There was also a thing called a Sage II (anyone else remember them) that
was a single-board 68000-based computer. The standard OS on that was the
p-system, although I am told that CP/M-68K was also available at some
point.
The Sage II was a nice machine to repair - one big flat board instantly
visible when you pulled the cover, all chips in sockets, and the
schematics in the user manual. They don't make 'em like that any more :-).
It was a fairly standard design - 68000 + 512K RAM + floppy controller
(Western Digital I think) + 2 serial ports + 8255 parallel port + GPIB +
glue logic.
Also, the first PERQ microcode implemented something called 'Q-code' which
was (I believe) an enhanced p-code - enhanced with things like raster-op
(bitblit) instructions. PERQ, of course, stood for 'Pascal Evaluation Real
Quick', and the machine was (in part) designed to run p-code - there's a
256-way branch operation to make it easy to do an instruction dispatch on
a bytecode.
A few months ago, there was a comment doing the rounds between a few
serious PERQ-fanatics that the PERQ should be renamed the 'jerq' (Java...)
and was essentially sold 17 years too early.
--
-tony
ard12(a)eng.cam.ac.uk
The gates in my computer are AND,OR and NOT, not Bill