Waterfall SDLC Methodology

According to a VersionOne survey (2007), nearly 70% of software development organizations are still using the Waterfall Method/Methodology -- in other words, not only is it the oldest and most well tested methodology -- but you're also in good company if you use it.

The Waterfall Method is comprised of a series of very definite phases, each one run intended to be started sequentially only after the last has been completed, with one or more tangible deliverables produced at the end of each phase.

Essentially, it starts with a heavy, documented, requirements-planning-and-sign-off's phase that outlines all the requirements for the project, followed by sequential phases of design, coding, test-casing, optional documention, verification (alpha-testing), validation (beta-testing), and finally deploment/release.

There are several pros for its insistence on a clear definition of requirements/goals up front (allowing better scheduling and estimating), but also some cons for it (hence the evolution of the Agile methodology).

The original 10 step Waterfall Methodology
The original SDLC -- the Waterfall Methodology -- is comprised of 10 steps intended to be executed sequentially, but -- depending on the size and complexity of the project -- phases can be combined or even overlap (see 6 Step Waterfall Methodology outlined below).

1. Initiation Phase: An opportunity is spotted, and is proposed in a formal Concept Proposal Document.
2. System Concept Phase:
* Deliverables:
o System Boundary Document (to define the scope or boundary of the concept),
o Cost Benefit Analysis,
o Risk Management Plan,
o Feasibilty Study. Typically evaluated in three areas:
+ economical,
+ operational,
+ technical.
+ Note:The feasibility study is sometimes used to present the project to upper management in an attempt to gain funding.
3. Planning Phase:
* Used as a reference to keep the project on track and to evaluate the progress of the MIS team.
* Deliverables:
o A Project Management Plan is developed .
* Note: Provides the basis of acquiring the resources needed to achieve a solution.
4. Requirements Analysis Phase:
5. Design Phase: The requirements are analysed in order to design the product's architecture.
6. Development Phase: The design is converted into reality and then white box tested by the development team.
7. Integration and Test Phase: The product is tested by the development team, Quality Assurance staff, and final users.
8. Implementation/Deployment Phase: The product is rolled out into a production environment.
9. Operation and Maintenance Phase: The system is monitored to ensure it contiinues to meet performance requirements, with periodic In-Process Reviews to suggest ways on improving the system.
10. Disposition Phase: The product is removed from service, with special enphasis on archiving the data, or moving to another system.

In smaller shops, the above 10 steps are often combined as follows:

Short Form (6 steps) of the Waterfall SDLC
As stated above, in smaller shops, or on smaller projects, several of the steps are combined into the following sets (the percentages are only suggested amounts):

* Initiation/Planning/Concept Phase (5% of the project)
* Requirements Analysis Phase (10% of the project)
* Design Phase (15% of the project)
* Development Phase (40% of the project)
* Integration and Test Phase (20% of the project)
* Implementation/Deployment Phase (10% of the project)

Note that the above numbers vary from shop to shop, although, according to this source, best-of-breed large shops have figures closer to the following:


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New York State Project Management SDLC Templates (Version 2)
Just to give you an idea of variants that you may encounter.

Practical Templates: SDLC
You can purchase templates for all the documents and report of the SDLC here.