Incremental Model
1
Group Members
• Adnan Mudassar (30178)
• Syed Muzammil Badar (30279)
2
Contents
• What is Incremental Model
• Why incremental model is used
• Characteristics of Incremental Model
• When to Use Incremental Model
• Activities of Incremental Model
• Advantages
• Problems
• Example
3
What is Incremental Model?
• Incremental Model is a process of software development where
requirements are broken down into multiple standalone modules of SDLC
• Incremental development is done in steps from analysis design,
implementation, testing/verification, maintenance.
• Each iteration passes through the requirements, design, coding and
testing phases.
• Each subsequent release of the system adds function to the previous
release until all designed functionality has been implemented.
4
Cont..
• Combine the advantages of Waterfall and
Evolutionary Model.
Requirements
Outline
Develop
Increment
Split into
increments
Validate
Increment
Design
System
Architecture
Integrate
Increment
Validate
System
Final
System
5
Cont..
• Prioritizes the services to be provided by the system.
• Maps these requirements to Increment based on
priority.
• Freezes requirement for the current Increment.
• Requirements for the later increments can evolve
concurrently.
• Each Increment release is a working system:
• Allows user to experiment.
• Can be put into service right away.
6
In the incremental model, software is developed in a series of
steps.
The incremental model
7
Why incremental model is used
• Generates working software quickly and early during the software life
cycle.
• This model is more flexible – less costly to change scope and
requirements.
• It is easier to test and debug during a smaller iteration. In
this model customer can respond to each built.
8
Characteristics of an Incremental module includes
• System development is broken down into many mini development projects
• Partial systems are successively built to produce a final total system
• Highest priority requirement is tackled first
Once the requirement is developed, requirement for that increment are
frozen
9
When to use Incremental models?
• Requirements of the system are clearly understood
• When demand for an early release of a product arises
• When software engineering team are not very well skilled or trained
• When high-risk features and goals are involved
• Such methodology is more in use for web application and product based
companies
10
Activities performed in incremental phases
Requirement Analysis
•Requirement and specification of
the software are collected
Design
•Some high-end function are
designed during this stage
Code
•Coding of software is done during
this stage
Test
•Once the system is deployed, it
goes through the testing phase
11
Incremental Model: Advantages
• Early utilization:
• the 1st increment satisfies the most critical requirement.
• Early increments can serves as prototypes.
• Lower risk of overall project failure.
• Most crucial and basic services are implemented first.
• It is flexible and less expensive to change requirements and scope
• This model is less costly compared to others.
12
Incremental Model: Problems
• Hard to map requirement into small increments (< 20,000 lines of
code).
• Becomes invalid when there is time constraint on the project
schedule or when the users cannot accept the phased deliverables.
• Contractual problems
• Requires good planning and design.
• Budget may over runs.
13
Example
14
15
16