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From: cberg@leadsv.UUCP (Charles R Berg)
Newsgroups: comp.software-eng
Subject: Re: Contemplating Purchase of "Excelerator" CASE Tool
Message-ID: <11394@leadsv.UUCP>
Date: 31 May 90 17:56:25 GMT
Reply-To: cberg@leadsv.LEADS.LMSC.COM.UUCP (Charles R Berg)
Organization: LMSC-LEADS, Sunnyvale, Ca.
Lines: 123

In some article, somebody wrote:
>Can you compare Excelerator with any other CASE tools for the same job?

I used Excelerator for about 18 months (over 3 years ago), and am now using StP
for about 2 years.  While I haven't done the SAME job with both tools, I can
compare how the two tools would work on the two jobs I did.

First, some philosophy.  Index Technology (authors of Excelerator) frequently
claims "We don't preach religion, we build churches."  What they mean is, they
don't rigidly enforce any given methodology with their tool, they provide the
framework in which to 'massage' standard methodologies into your company
preferences.  They offer a companion product, Customizer, that allows you to
define new diagram types, new entities, new symbols, and new relationships
between objects.  With this complete set of tools, it is relatively easy to
make the rules you want, and capture the information you want.  One other
important philosophy is that there are virtually no methodology rules
enforced when drawing a diagram.  Rules are applied upon analysis of an
existing diagram.

IDE, (authors of StP), on the other hand, advertises "Visible Connections" and
"Open Architecture".  What this means is that many of the parameters that
define the tools behavior are configurable in ASCII files.  So, it is actually
trivial to change the information captured about any given object in the
database.  However, it is a major effort, but do-able (I know, I'm doing it),
to add new diagrams, entities, and relationships.  In addition, there are a
number of methodology rules that are enforced before a drawing is allowed into
the database.  Other rules are further applied upon analysis.

So, some comparisons.

Dataflow Diagrams.  Excelerator allows the user to build a directed graph of
diagrams.  If you want to define 3 identical processes that share the load in
a multi-processor architecture, you can draw 3 process bubbles, label them as
you wish, and decompose all 3 to the same lower-level diagram.  StP would
require that two of the process bubbles be annotated as being identical to the
3rd, which would be actually decomposed.  I AGREE, its not Yourdan methodology,
but if its important to you to want to do it anyway, then Excelerator makes
it easier.  Excelerator also allows you to decompose process bubbles
recursively, and will allow you to decompose a process bubble to a structure
chart if you want.  In addition, Excelerator process ID's are free-form text,
while StP enforces numerical hierarchy.  So in summary, both tools provide
an environment in which you can do standard Yourdan dataflow diagramming.  If
your company has other needs, Excelerator allows you greater methods
flexibility.

Other Diagrams.  If you will allow some generalization in the interest of
brevity, I would say that the previous summary is generally true.  Both tools
provide an environment for standard methodology, but Excelerator allows
greater flexibility in tailoring those methods to your company needs.

Document Production.  Both tools provide a mechanism for extracting information
from the database and exporting into 'desktop publishing' systems.  Both
allow you to customize the attributes that are defined for each object type.
StP provides this by editting ASCII configuration files, Excelerator provides
a screen editor tool.  The real differences appear when you want to use that
information.  StP has a very powerful, 4th generation language that allows you
to make database queries based on these attributes.  You can select, sort, and
manipulate the information quite extensively.  It also provides a relatively
complete and powerful set of document formatting commands.  Excelerator's
document production, on the other hand, is more limited to extracting
diagrams and objects, and the block of information stored in the database
about each.  However, Excelerator does have a report writer, separate from its
document production tool, that allows you to make ad-hoc queries very quickly
and easily.  "Give me the names of all dataflow diagrams containing process
bubbles that do not decompose to other dataflow diagrams" is a very easy
query to create, and can be saved for later use.  These queries can also be
included in documents.  StP would require that a separate document script be 
written in their DPS language.  Also relatively  easy, but a bit more time-
consuming, and not something you would likely  want all of your users to be
doing.

So, (this is getting kinda long, isn't it) as far as the two projects I worked
on using these tools.

The first was for a start-up company, and we needed a tool to capture object-
oriented design information (back before either tool provided such a thing).
We also wanted to capture a multiple-window, pop-up menu user interface, in
addition to normal data structures and structure charts.  High quality,
polished documents were not a requirement.  I was quite pleased with our choice
of Excelerator, and if I had it to do over again, I would choose it again.

The second project was for my current employer, a government contractor.  Here,
high-quality document production was paramount.  We are using StP (obviously),
and are succesfully pushing its document production capability beyond what
IDE ever expected it to do.  Of course, the underlying database necessary to
produce our complex documents is also supported by the tool.  Once again, I
still believe we have the right tool for the job.

I guess another generalization I can offer is this.  Excelerator is easier and
more flexible at getting information into the database.  StP is more powerful
at being able to manipulate and document the information captured.  Now, if I
could have the methods flexibility of Excelerator with the powerful database
and document production of StP....

Now, in case I haven't made myself clear, both of these tools are good tools.
They each have their strengths and weaknesses.  I have successfully used both,
on two very different programs.  In no way are my comments intended to
recommend one over the other.

In conclusion, you have now heard from several people who have said (in effect)
"The best tool is a matter of your requirements and your preferences."  You
have to do your homework.  Get evaluation copies of every tool you're thinking
about buying and use them.  Try to do meaningful little projects with each.  No
tool is perfect - you have to find the one with strengths that complement your
needs, and weaknesses that don't get in your way.

One other good piece of advice you received bears repeating.  The amount of
work you put into selecting the right tool is SMALL compared to the amount of
work necessary to learn how to use it, support it, maintain it, extend it, and
do everything else your going to want/need to do.  The cost of purchasing the
tool is SMALL compared to the cost of the effort of using it.  If you aren't 
ommitted to that effort and expense, don't bother.

I hope this helps.

Chuck Berg

PS: I am an independent consultant.  I have no ties what-so-ever with either
Index Technology or IDE.  I also do not speak for my current employer.  I am
offering personal opinions based on personal experience. If I have inaccurately
stated features or limitations of either of these tools, I apologize, and
encourage the vendors to post corrections.  I personally think it would be
great if some CASE vendors would get involoved in discussions in this group.