SYSTEM LIFE CYCLES
The waterfall model
describes a development
method that is linear and
development has distinct
goals for each phase of
development. Once a phase
of development is
completed, the development
proceeds to the next phase
and there is no turning back.
ADVANTAGES OF THE
A schedule can be set with deadlines for each stage of development .
Each phase of development proceeds in strict order, without any
The amount of resources required to implement this model are
Documentation is produced at every stage of the software's
development. This makes understanding the product designing
Does not allow for much reflection or revision. Once an application is in
the testing stage, it is very difficult to go back and change.
Small changes or errors that arise in the completed software may cause a
lot of problems.
Until the final stage of the development cycle is complete, a working
model of the software does not lie in the hands of the client, so you never
know if it is what they asked for.
Often, the client is not very clear of what he exactly wants from the
software. Any changes that he mentions in between, may cause a lot of
This model of
development combines the
features of the prototyping
model and the waterfall
model. The spiral model is
favoured for large,
ADVANTAGES OF THE
Its design flexibility allows changes to be implemented at several
stages of the project.
The process of building up large systems in small segments makes
it easier to do cost calculations.
The client, who will be involved in the development of each
segment, retains control over the direction and implementation of
The client's knowledge of the project grows as the project grows,
so that they can interface effectively with management.
DISADVANTAGES OF THE
Highly customized limiting re-usability.
Applied differently for each application.
There is a requirement for further explanation of the steps
involved in the project such as breakthrough, blueprint,
checkpoints and standard procedure.
The models work best for large projects only, where the costs
involved are much higher and system pre requisites involves
higher level of complexity.
The systems development life
cycle (SDLC) is a conceptual
model used in project
management that describes the
stages involved in an
development project, from an
initial feasibility study through
maintenance of the completed
ADVANTAGES OF CYCLICAL
Clearly defined stages.
Simple to understand and use.
Well understood milestones
Easy to arrange tasks.
It’s difficult to measure progress within stages.
Cannot accommodate changing requirements.
No working software is produced until late in the cycle.
Risk and uncertainty is high with this process model.