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From: kend@data.UUCP (Ken Dickey)
Newsgroups: comp.software-eng
Subject: Re: Second System Effect
Message-ID: <448@data.UUCP>
Date: 22 Feb 91 19:55:37 GMT
References: <30512@mimsy.umd.edu>
Organization: Microcosm, Beaverton, OR
Lines: 40

dalamb@umiacs.umd.edu (David Lamb) writes:

>In "The Mythical Man-Month", Fred Brooks (1975) described the "second system
>effect"
...
>Do y'all believe it's still a problem these days?

>David Alex Lamb				internet: dalamb@umiacs.umd.edu

There is a variant that is also true: arithmetic increases in computing power
[by engineering] leading to geometric increases in expectation [by marketing].

A fundamental problem is lack of recognition of differences in scale
and what that means for system structuring and complexity.  

As an analogy, many people have built bridges over streams by throwing
a log over them.  In the fancy case, use 2 logs and nail some boards
between them.  To span a ravine, one might use a steel-ibeam/truss
design.  To get cars and trucks across San Francisco Bay, one might
use a suspension design, again with different materials.

Many people today are still trying to take high-level assembler/
device-driver technology and scale it up for major software systems
and complaining that "it is very difficult to get a log big enough to
cross the bay."  Unlike engineering professions, many (most?) software
professionals are not trained to judge project scale or evaluate
software implementation technologies.

[In the "real world" I still see many people who could have been
bottled in 1975.  They are totally unaware that there has been
technical progress in software development technology during the
intervening years (or for that matter of the advanced techniques
available at that time).]

So my answers are (10 years in industry) [1] Yes, the "second system"
effect is real, and [2] software designers should be aware of "scale
shifts" as well.


-Ken Dickey				kend@data.uucp


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