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From: dalamb@qucis.queensu.CA (David Lamb)
Newsgroups: comp.edu,comp.lang.ada,comp.lang.misc
Subject: Re: Teaching Concurrency
Message-ID: <499@qusundl.queensu.CA>
Date: 11 Jan 90 14:52:43 GMT
References: <7588@hubcap.clemson.edu> <602@agcsun.UUCP>
Reply-To: dalamb@qucis.queensu.CA (David Lamb)
Organization: Queen's University, Kingston Ontario
List-Id: <comp.lang.ada>

In article <602@agcsun.UUCP> marks@agcsun.UUCP (Mark Shepherd) writes:
>In real life (whether industrial, business, scientific research, or whatever),
>multi-tasking applications carry substantial penalties
>in complexity and resource utilization, and should only be used when
>appropriate. (Of course, NOT using tasking when it should be used has
>equally dire consequences).
>
This may be true now, but will it continue to be true?  Twenty years ago
people told us to avoid subroutine calls because of the unacceptable overhead;
today there are lots of production compilers that do better than most
programmers can (with inline expansion, special calling sequences, and so
on).

In the long term we're better off teaching the right abstractions, then
pushing our translators to generate efficient code.  In the short term
maybe some people need to hand-translate to efficient non-tasking code,
just as they once needed to hand-translate code with lots of subroutine
calls into code that avoided it.  As with the subroutine issue, I think
that even today the fraction of tasking code that needs such translation
is smaller than many people think.

David Alex Lamb			ARPA Internet:	David.Lamb@cs.cmu.edu
Department of Computing				dalamb@qucis.queensu.ca
    and Information Science	uucp:   	...!utzoo!utcsri!qucis!dalamb
Queen's University		phone:		(613) 545-6067
Kingston, Ontario, Canada K7L 3N6