Zusammenfassung der Ressource
Software Development- waterfall
model and RAD
- WATERFALL LIFE CYCLE MODEL
- Each step is completed at a time from
start to finish
- Each step/ stage must be
completed before you can move
onto the next one
- Better used for smaller projects
because the requirements are well
known-and any changes would
mean that you can easily jump
back to the previous stage
- Stages of the life cycle:
- 1. REQUIREMENTS-
expectations and goals of
the project are defined in
this stage. System analysts
do this.
- 2. DESIGN- after the goals have
established, work commences on
designing the product and plans
are made.
- 3. CONSTRUCTION-
the software/code
for the project is
written
- 4. TESTING AND DEBUGGING-
software is tested to make sure
is meets the client's
requirements
- 5. INSTALLATION- product
is implemented according
to the agreed
reuirements
- 6. MAINTENANCE- the product
is sent to the client and
support of the product is put
into place
- ADVANTAGES
- Well suited for projects
where quality is
emphasised over cost
or time-requirements
- Lack of any
overlap between
phases avoids
confusion
- High
visibility-demonstrate
output can be seen
- DISADVANTAGES
- Not suitable for large-scale
projects
- Changes in requirements later in
the stage may take longer to
create as you have to go back to
the original stage
- Not suited for the fast
changing computers in today's
world. Software may not work
on different computers
- RAD- rapid application development
- Emphasising rapid
prototyping and iterative
delivery.
- Produces
successive
prototypes of the
software
- Rigidly placed
schedule that defers
design
improvements to
the next product
- MAIN STAGES OF RAD
- Make of improve a
prototype
- Evaluate the prototype
- Repeat until the job is done
- ADVANTAGES
- User involvement- the user can use
the software and give feedback on a
live system-so no time will be
waster going back to the design
level as you do it as you go along
- Errors will be found
much earlier on in
the stage
- DISADVANTAGES
- Requires highly skilled
programmers and designers
- Only a system that can be
modulised can use RAD