The General Model
Software life cycle models describe phases of the software cycle and
the order in which those phases are executed. There are tons of
models, and many companies adopt their own, but all have very similar
patterns. The general, basic model is shown below:
Each phase produces deliverables required by the next phase in the
life cycle. Requirements are translated into design. Code
is produced during implementation that is driven by the design.
Testing verifies the deliverable of the implementation phase against
requirements.
Requirements
Business requirements are gathered in this phase. This phase
is the main focus of the project managers and stake holders.
Meetings with managers, stake holders and users are held in order to
determine the requirements. Who is going to use the system?
How will they use the system? What data should be input into the
system? What data should be output by the system? These are
general questions that get answered during a requirements gathering
phase. This produces a nice big list of functionality that the
system should provide, which describes functions the system should
perform, business logic that processes data, what data is stored and
used by the system, and how the user interface should work. The
overall result is the system as a whole and how it performs, not how it
is actually going to do it.
Design
The software system design is produced from the results of the
requirements phase. Architects have the ball in their court
during this phase and this is the phase in which their focus
lies. This is where the details on how the system will work is
produced. Architecture, including hardware and software,
communication, software design (UML is produced here) are all part of
the deliverables of a design phase.
Implementation
Code is produced from the deliverables of the design phase during
implementation, and this is the longest phase of the software
development life cycle. For a developer, this is the main focus
of the life cycle because this is where the code is produced.
Implementation my overlap with both the design and testing
phases. Many tools exists (CASE tools) to actually automate the
production of code using information gathered and produced during the
design phase.
Testing
During testing, the implementation is tested against the
requirements to make sure that the product is actually solving the
needs addressed and gathered during the requirements phase. Unit
tests and system/acceptance tests are done during this phase.
Unit tests act on a specific component of the system, while system
tests act on the system as a whole.
So in a nutshell, that is a very basic overview of the general
software development life cycle model. Now lets delve into some
of the traditional and widely used variations.
Software life cycle models describe phases of the software cycle and
the order in which those phases are executed. There are tons of
models, and many companies adopt their own, but all have very similar
patterns. The general, basic model is shown below:
Each phase produces deliverables required by the next phase in the
life cycle. Requirements are translated into design. Code
is produced during implementation that is driven by the design.
Testing verifies the deliverable of the implementation phase against
requirements.
Requirements
Business requirements are gathered in this phase. This phase
is the main focus of the project managers and stake holders.
Meetings with managers, stake holders and users are held in order to
determine the requirements. Who is going to use the system?
How will they use the system? What data should be input into the
system? What data should be output by the system? These are
general questions that get answered during a requirements gathering
phase. This produces a nice big list of functionality that the
system should provide, which describes functions the system should
perform, business logic that processes data, what data is stored and
used by the system, and how the user interface should work. The
overall result is the system as a whole and how it performs, not how it
is actually going to do it.
Design
The software system design is produced from the results of the
requirements phase. Architects have the ball in their court
during this phase and this is the phase in which their focus
lies. This is where the details on how the system will work is
produced. Architecture, including hardware and software,
communication, software design (UML is produced here) are all part of
the deliverables of a design phase.
Implementation
Code is produced from the deliverables of the design phase during
implementation, and this is the longest phase of the software
development life cycle. For a developer, this is the main focus
of the life cycle because this is where the code is produced.
Implementation my overlap with both the design and testing
phases. Many tools exists (CASE tools) to actually automate the
production of code using information gathered and produced during the
design phase.
Testing
During testing, the implementation is tested against the
requirements to make sure that the product is actually solving the
needs addressed and gathered during the requirements phase. Unit
tests and system/acceptance tests are done during this phase.
Unit tests act on a specific component of the system, while system
tests act on the system as a whole.
So in a nutshell, that is a very basic overview of the general
software development life cycle model. Now lets delve into some
of the traditional and widely used variations.
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