Re: Task-based vs. System-Based Procedures

["Anthony Markatos" <tonymar -at- hotmail -dot- com>]

"Anthony Markatos" <tonymar -at- hotmail -dot- com> wrote

Properly utilizing Structured Systems Analysis and Design (SSAD) - the most 
prevalent of the formal analysis/design techniques - requires that the 
developer "approach" the application the same way that the end-user does.

Yevonne DeGraw responded:

This is perhaps true in idealized cases for the subset of software design 
that creates data processing applications for use only by endusers where 
there is a defined workflow. However, there are other types of software that 
don't follow such design models.

Tony Markatos responds:

1.) SSAD methodologies not only include task modeling (Systems Analysts 
refer to such as "function" modeling - same thing) techniques, they also 
include techniques for capturing  end-user data relationships - entity 
relationship diagrams (ERDs).  Even the most ad-hoc decision support system 
needs data modeling.

And even if only data models are being created, the analyst has to have the 
exact same "approach" to the system as do the end-users - otherwise he will 
miss essential data relationships in his design.

2.) You basicaly state (and this is a very commonly held viewpoint) that for 
some systems, an end-user task analysis is not required because there are no 
predefined tasks.  Let's look at an extreme example of such a system: a pure 
ad-hoc decision support system.  Question: How can we create an (ad-hoc) 
decision support system if we do not know what decisions are being 
supported? Logically, the need for an end-user task analysis still exists - 
although it may be a lot harder to accomplish such.  (However, it has been 
my experience that doing such is a lot LESS difficult than we are typically 
lead to believe.)

Yevonne DeGraw said:

This [SSAD] is a totally different world than object-oriented design.

Tony Markatos responds:

I agree with what Ed Yourdon (guru in SSAD and OOAD) said - that the first 
steps in a OOD project are the creation of ERD's [and to the degree 
necessary DFD's].  OO lacks any tools that actually guide one through the 
analysis phase - that makes "holes" in the anlysis glaringly obvious.

Tony Markatos








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