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From: tenney@well.UUCP (Glenn S. Tenney)
Newsgroups: comp.lang.forth
Subject: Re: Multi-user Forth
Message-ID: <3794@well.UUCP>
Date: Fri, 21-Aug-87 04:27:08 EDT
Article-I.D.: well.3794
Posted: Fri Aug 21 04:27:08 1987
Date-Received: Sat, 22-Aug-87 19:55:50 EDT
References: <9.2122EF36@circle.UUCP> <2573@tekgvs.TEK.COM> <645@cfa.cfa.harvard.EDU>
Reply-To: tenney@well.UUCP (Glenn S. Tenney)
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 19

I believe that "you" must understand that there is a difference between
multitasking and interrupts.  A hi speed time-critical routine really should
be an interrupt routine written in hi level or assembler.  By having the
context switch occur at PAUSE (which, btw, is implied at any I/O type
word such as BLOCK) a whole slew of problems disappear.  It then becomes
the programmer's responsibility to put PAUSE in lot's of extra places
when you think you're going to be doing something cpu intensive AND when
you know it's safe.  It's also your job to be sure things are safe before
ANY I/O word.

All in all, multitasking with PAUSE is much nicer, but it is not what most
CS people are used to since there is no time slicing.  There are MANY
time critical applications running tons of software on lots of terminals etc.
using just such a multitasker.

Btw, such a multitasker can be written entirely in hi level.  I did it
to test things out about 4 years ago (or was it 5?).

Glenn Tenney