System Development Methodology Flashcards
What is a methodology?
A coherent set of methods used in carrying out some complex activity
Waterfall model
System development flows downwards like a waterfall from one activity to the next in a strict order
Waterfall tasks are…
ordered, well defined and one-way
How Waterfall works
Documents and deliverables are evaluated then approved. If errors are found, they are rejected and reworked.
Requirements for Waterfall
are defined, plan-driven and set in stone
Analysis in Waterfall is…
client-driven
Developer-driven tasks in Waterfall are…
Design, Implementation, Validation
Example of a Waterfall methodology
Structured Systems Analysis and Design Method (SSADM)
When to use Waterfall methodology?
Computerising existing manual systems without major changes, Systems not expected to change over time, Processes well understood and defined, Systems rather isolated not integrated
3 constraints in Waterfall
Requirements fixed first, Delivery when ready, Cost/Resources expand as needed to meet requirements
Advantages of Waterfall
Practical and easy to use, Simple structured approach, Emphasis on documentation, Traceability
Disadvantages of Waterfall
It’s slow, Distance from users, Testing is left last, Requires time, resources and cost