Path: utzoo!attcan!uunet!mcsun!ukc!pyrltd!tetrauk!rick
From: rick@tetrauk.UUCP (Rick Jones)
Newsgroups: comp.object
Subject: Re: Software is not Hardware
Message-ID: <517@tetrauk.UUCP>
Date: 9 Jul 90 10:24:02 GMT
References: <197@geocub.greco-prog.fr>
Reply-To: rick@tetrauk.UUCP (Rick Jones)
Organization: Tetra Ltd., Maidenhead, UK
Lines: 36

In article <197@geocub.greco-prog.fr> bnfb@geocub.greco-prog.fr (Freeman Benson) writes:
>Software is not hardware---the chip/board analogy only goes so far.  
>But why?  Mr. Stroustrup pointed out one reason: striving for the best.
>A similar reason is that the problem is software DESIGN, not manufacturing.
>Design is still hard, software or hardware, because it is a mental
>activity.  Hardware companies where I have worked took a long time to
>design their products, just as the software companies took a long time
>to write their software.  Sure, some designs are well known, but then so
>are some programs: the database 4GLs come to mind.  They key is that,
>with or without object-oriented languages, with or without code libraries,
>with or without tools, the problem of design is hard.  Yes, certain tools help,
>but only for well-understood problems---in other words, making clones is easy.
>But we knew that.
>
>Bjorn N. Freeman-Benson

I agree entirely - software is all about design.  Even programming, whether or not you
are using an OOPL, constitutes generating a detailed DESIGN.  The idea that OO methods
allow a programmer to "construct" software by fitting together "components" just pushes
the hardware analogy too far until it doesn't really fit.  Software re-use is about
re-using the design specification for a component - the component is the _object_ which
only appears when the program executes;  the design specification is the program, written
as a class in an OOPL.

Re-use by inheritance in involves creating a new design based on an existing one;  this
is distinctly different from adapting an existing component to a new purpose.  Thinking
too much in terms of the hardware analogy can lead to misconception and confusion about
what the software task is really all about.

I could go on at length but I don't have the time (net bandwdith wins this time).  But
it's an important issue when considering what a programming language is supposed to be.

-- 
Rick Jones					You gotta stand for something
Tetra Ltd.  Maidenhead, Berks			Or you'll fall for anything
rick@tetrauk.uucp (...!ukc!tetrauk.uucp!rick)	     - John Cougar Mellencamp