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Services - Classical Methodology 
[RAD]
[Classical]
[Glossary]
[Print]
The Waterfall process follows
a set and pre-determined path. It gets its name from the visual
appearance of the schedule that results from the methodology. This
chart shows a typical Waterfall schedule:
The Waterfall methodology
is used when the customer has a detailed understanding of the system
requirements, and it is possible to create a System Specification within
a reasonable effort, and therefore cost. Systems built with this
methodology are usually billed hourly in the Requirements/Analysis phases.
The project can be billed fixed cost from the creation of the System
Specification Document (SSD - the System Architecture and Design) through
the later phases that lead to final delivery of the system and ending
with System Test. The SSD will usually contain the details required
to build the system including a proposed cost and schedule.
Advantages of Classical
Methodology:
- Known cost and
schedule after creation of the System Specification Document (SSD).
- The SSD documents
the system as designed. This may be very important for companies
needing to list assets for purposes of company buyouts, annual reports,
etc.
- There is ample
documentation on how to proceed with this methodology. It has
a long history of success in the computer industry.
Disadvantages of
Classical Methodology:
- Changes and additions are
contractual changes requiring formal customer approvals and contract
revisions. Costs must be renegotiated if changes are made after construction
has begun.
- Users must wait
until the end of the project, or at least until a major portion of it
is complete, before seeing the results.
- The early phases
of the project may take longer than the RAD approach (defined below)
due to the time required to generate the detail necessary in the SSD
for a software group to create the system.
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