Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!weyrich!orville
From: orville@weyrich.UUCP (Orville R. Weyrich)
Newsgroups: comp.software-eng
Subject: Re: Pictorial Case Tools
Message-ID: <1991May25.080657.3447@weyrich.UUCP>
Date: 25 May 91 08:06:57 GMT
References: <1991May23.185623.24457@agate.berkeley.edu> <19874@crdgw1.crd.ge.com> <1991May24.202600.14452@netcom.COM>
Reply-To: orville@weyrich.UUCP (Orville R. Weyrich)
Organization: Weyrich Computer Consulting
Lines: 69

In article <1991May24.202600.14452@netcom.COM> jls@netcom.COM (Jim Showalter) writes:
>>For me the main purpose of the pictorial case tools is to capture the design
>>at as early a stage as possible so that we can begin testing for consistency
>>and omissions with automated tools.
>
>I guess the issue I have with this is not so much the checking--I agree
>that tools automate checking--as it is the notion that there is anything to
>BE checked that is an indicator of good design. Yes, a tool can automatically
>check that all my bubbles and arcs line up properly, but the fundamental
>issue I have with this is: what proof, if any, is there that those bubbles
>and arcs have anything to do with a good design? It gets back to the same

A person's ability to think about a problem depends on their ability to 
express the relevant aspects of the problem in some sort of precise
language which is easy to use. The language may be verbal or visual. 

The question becomes, "Do bubbles and arcs express some relevant aspect
of the system being designed in a convenient and precise language?"

See my comments below regarding this question.

>issue in the metrics thread in this same group: for metrics to be of value,
>one has to have confidence that the metrics are measuring something that
>has a correlation to project success; for design tools to be of value, one
>has to have confidence that the tools are enforcing things that have a
>correlation to good design. I think what designers do is largely ephemeral:
>it takes place in the space between their ears. Good designers do something
>that produces a good design. Most people are not good designers. I doubt
>that good designers arrive at good designs by manipulating bubbles and arcs
>in their brains (I could be wrong here--anybody who is a good designer care
>to describe how they do what they do?).

Several things occur to me:

1) A software tool's usefullness depends on how well it facilitates
   mapping between the problem and solution domains.

2) CASE tools are largely visually oriented. 

3) So are some [but not all] people. [Some people are verbally oriented, etc.]

4) Sensory-mode mismatch tends to lead to loss of communication effectiveness.

5) The degree to which CASE tools facilitate good design therefore depends
   on the degree to which the designers are visually oriented. 

6) This then raises the question: what percentage of the designers are
   comfortable in visual mode? An interesting topic for a human-factors
   study.

7) I like to think that I am a good designer :-). I am comfortable in visual
   mode, but prefer to manipulate bubbles and arcs on paper [or blackboards:
   I do not care for the solvents in dry-erase markers]. It is not the only
   thought mode that I use [for some aspects of a problem, for example, I
   prefer decision tables -- more verbally oriented, but still with a
   visual (spatial) component].

8) Good "Form" seems to be necessary but not sufficient requirement for a
   good design.

9) CASE tools that can do consistency checks help ensure good Form, and hence
   good design.

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Orville R. Weyrich, Jr., Ph.D.                   Certified Systems Professional
Internet: orville%weyrich@uunet.uu.net             Weyrich Computer Consulting
Voice:    (602) 391-0821                         POB 5782, Scottsdale, AZ 85261
Fax:      (602) 391-0023                              (Yes! I'm available)
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