We have already discussed one of the most popular tools: Data Modeling: [ a5.html ] and this discusses other ways of "Drawing a picture of a system". Later we will get to some very detailed tools [ r1.html ] (Rules and procedures), [ r2.html ] (requirements), and [ r3.html ] (Specifications).
A glossary is one of the must useful documents you can develop when analysing an
All a glossary does is record the meanings given to the words and phrases that are used in different parts of the enterpise.
You can use 3><5 cards, text files, spread sheets, or even a small data base.
A glossary can grow into a data dictonary if you add detailed information on the processes, external entities, and data for the enterprise. This in turn becomes the information you must have to design new systems.
A scenario is no more than a sequence of very simple actions by subjects.
Make each step in the sequence follow this syntax
where a direction is one of
The subjects, objects, and targets can be any noun phrase.
Write Basic Scenario describing what happens when you
Notice that a basic scenario has no branches, conditions, exceptions, extensions.
For these an activity diagram can be used ... with each activity documented by a basic scenario
[ usage_scenarios.html ]
. . . . . . . . . ( end of section Basic Scenarios) <<Contents | End>>
What is a prototype
|A prototype||A prototype is not|
|can be an executable program||useful to the users|
|can have a data base||full of all the real data|
|demonstrates how something appears to work||a finished product|
|works on some input||completely correct|
|is produced quickly||a high quality long term project|
|runs||efficient on real data|
|tests ideas||a program test|
|is for the user||always executable code|
|provokes discussion||the best possible solution to the problem|
|Can be used to sell a project||a promise that a project is feasible|
The term comes form the movie industry where directors use them. You will often find images of story boards as "extras" on DVDs. [ search?cat=img&cs=utf8&q=story+board&rys=0&itag=crv ]
These are not high-tech prototypes. Use a board and stick cards on it.
Used as a basis of planning and discussion.
A mock up looks like the real thing and may even do some things
but is not properly constructed.
[ search?cat=img&cs=utf8&q=Mock+up&rys=0&itag=crv ]
It's possible the term comes from publishers. A computer example is faking a web page to show its look-and-feel.
Many automobile companies produce strange and wonderful one off
cars in exhibitions to show what is possible.
[ search?cat=img&cs=utf8&q=concept+car&rys=0&itag=crv ]
Most don't make it into production.
Use to sell a new system to management?
Once upon a time electronic engineers would try out ideas on the kitchen table
and use a bread board to hold the wires in place.
To this day you can buy special electronic breadboards: [ search?cat=img&cs=utf8&q=Bread+board&rys=0&itag=crv ] Typically an untidy mess of wires with many inputs, meters, and probes attached to it.
Used by software people to try out an algorithm -- full of extra outputs
and with a user interface designed for techies. Don't let the user
A scale model has all the functionality of the final system but
does not have the full data base. It's purpose is to spot
performance problems early.
. . . . . . . . . ( end of section Prototypes in other areas) <<Contents | End>>
. . . . . . . . . ( end of section Prototypes) <<Contents | End>>
Logical and Mathematical Models
There have been experiments in using logic and discrete math
to describe the behavior of a system in abstract form and
then execute the model to see if the ideas work. It
is also possible to manipulate them to search out unwanted behaviors.
These are a part of
[ ../cs556/ ]
. . . . . . . . . ( end of section System Modeling) <<Contents | End>>