UCSD P-System & "compile once, run anywhere"

From: Hans Franke <Hans.Franke_at_mch20.sbs.de>
Date: Thu Mar 28 09:05:49 2002

> > A friend was claiming that with the UCSD P-System, one could "compile once"
> > and then "run anywhere" (where "anywhere" means different kinds of
> > computers running the P-System, not different instances of the same computer).
> > Was this true?
> NO
> although there were a few machines for which it would be true.

of Course yes ... well sort of - see below

> > Did users commonly compile on system A and then take the P-Code to
> > system B and run it successfully?
> > I'd have thought that media incompatibility would have tended to
> > limit this capability.

> You are correct; your friend AND the UCSD vendors weren't.
> SEVERAL systems would work, but their concept of a "universal format" was
> not thought through. Due to disk hardware incompatabilities, it was NOT
> possible for Apple and IBM (just two as an example) to share a "universal
> disk format", although they DID advertise (FALSELY) exactly that.

Now, here we are talking about two things:
#1 is is the platform independant coding of an application, which
is accomplished by using the same structure across all platforms.
#2 is about different mass storage hardware. and here of course
an operating system could do next to nothing.

Because of #2 you raerly could use a disk from one system on another
system, so software distributors had to do media for each system.
Well, didn't we have the same situation even within the way more
homogenus environment of CP/M ? Where you had to state machine and
diskette format when ordering a copy of word star ?

(In fact I even remember the same situation for MS-DOS - at least
during the time when manufacturers still tried to build better
systems, and not just faster versions of the same old crap.)

There have been even GRAPHIC games which have been done in
UCSD P-Code and ported to other computers without big trouble.
One of the most classic games of all times: Wizardry.

> > Was any commerical P-System software sold that was a single
> > binary,
> ^^^^^^
> The basic concept behind it was the distribution of software NOT as a
> binary, but as a platform independent "P-code" that was run on a
> "P-code" interpreter.

Well, the P code IS the binary format of the programms. Just as
the so called Bytecode is the binary format for Java.

> > but the vendor expected the user to be able to install/run it on
> > any brand/model of P-System? (Or, did vendors have to produce a version
> > for every platform?)

> It combined all of the convenience of software development of a compiler
> with the speed of execution of an interpreter.

Well, the speed difference wasn't that big between the
result of 'real' Compilers (fortran for example) and
the UCSD-P version of Fortran. As so often it depended
on your kind of application.


BTW: Total different thing - has anybody erver tried to do a Java to
UCSD P-Code compiler ? Could be some fun :)

VCF Europa 3.0 am 27./28. April 2002 in Muenchen
Received on Thu Mar 28 2002 - 09:05:49 GMT

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