Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!mailrus!tut.cis.ohio-state.edu!osu-cis!att!ihlpb!tainter
From: tainter@ihlpb.ATT.COM (Tainter)
Newsgroups: comp.arch
Subject: Re: Software Distribution
Message-ID: <8619@ihlpb.ATT.COM>
Date: 26 Aug 88 00:27:11 GMT
References: <891@taux01.UUCP> <1988Aug19.175624.19835@utzoo.uucp> <3503@encore.UUCP> <847@stride.Stride.COM>
Reply-To: tainter@ihlpb.UUCP (55521-Tainter,J.A.)
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 39

In article <847@stride.Stride.COM> mitch@stride.stride.com.UUCP (Thomas Mitchell) writes:
>Caution: p-Code, p-System have some prior use and perhaps
>trademark  associated with them.  Now called the "Power System"
>by Pecan of Brooklyn it is an interpreted OS.  

>It had its origins at UCSD and is the origin of UCSD Pascal (aka
>Apple Pascal).

There is a trademarked thing called "UCSD p-System".
But p-code is not UCSD's.  UCSD just did an extension of Wirth's
original p-code system.
P-code is how Wirth did his original implementation of Pascal.
M-code is how he did his original implementation of Modula-2,
as is what the Lilith runs.

I don't know about the original Modula.

>Their [UCSD's] p-Code (pseudo code) is portable from one machine to
>another.  Their CODE file format has a field which lets the
>interpreter determine the byte sex of the p-code.

Yup.  And it cripples all programs down to 16 bit integers, 16 bit addresses
(although text addresses can be fudged through segments).
This is a nasty thing to do to a 680x0.  The Macintosh version
had a non-portable 32 bit integer extension and Pecan has recently
released a 32 bit version of the Power System.  I doubt though, that
code is portable between the 16 bit and 32 bit versions.

What p-code is really good for is shoe horning onto small machines.
p-code is very compact, and the segmentation allows some virtual memory
albeit at a significant peformance hit.  I also rather line units as
a for of modularity.

>Thomas P. Mitchell (mitch@stride1.Stride.COM)
>Phone: (702)322-6868	TWX: 910-395-6073	FAX: (702)322-7975
>MicroSage Computer Systems Inc.

First it was Sage.  Then it was Stride Micro.  Now it's MicroSage ?

--j.a.tainter