Module 2

Software Process

A software process:

- a collection of work activities, actions, tasks, which are performed when software is to be created.


2 Process activities


Framework activities : the activities are appicable to all software project, the size are complexcity.
(communication;planning;modeling;construction; and deployment) 


Umbrella activities : applied throughout a software project, manage and control progress,quality,change and risk.
(project tracking and control, risk management; software quality assurance;technical reviews;configuration management)


Prescriptive Process Models

~ Waterfall Model ~

Advantage
- Easy to understand and implement.
- Widely used and known (in theory!).
- Reinforces good habits: define-before- design, design-before-code.
- Identifies deliverables and milestones.
- Works well on mature products and weak teams.
Disadvantage 
- Idealized, doesn’t match reality well.
- Doesn’t reflect iterative nature of exploratory development.
- Unrealistic to expect accurate requirements so early in project.
- Software is delivered late in project, delays discovery of serious errors.
- Difficult to integrate risk management.
- Difficult and expensive to make changes to documents
- Significant administrative overhead, costly for small teams and
  projects


The waterfall model performs well for products with clearly understood requirements or when working with well understood technical tools, architectures and infrastructures. Its weaknesses frequently make it inadvisable when rapid development is needed. In those cases, modified models may be more effective.

~ Incremental Model ~

Advantages
- Generates working software quickly and early during the software
   life cycle.
- More flexible – less costly to change scope and requirements.
- Easier to test and debug during a smaller iteration.
- Easier to manage risk because risky pieces are identified and
   handled during its iteration.
- Each iteration is an easily managed.
Disadvantages
- Each phase of an iteration is rigid and do not overlap each other.
- Problems may arise pertaining to system architecture because not all requirements are gathered up front for         
   the entire software life cycle.

~ Prototyping ~

Advantages 
- Reduce rate of error since the prototype is repeated so many times.
- Prevent the wrong invention.
- Help the user to understand.
- Increase customer satisfaction.
- Reduces development costs.
- Requires user involvement.
Disadvantages
- less documentation will result difficult maintenance.
- User confusion of prototype and finished system.
- Users expect the performance of the ultimate system to be the same as the prototype.

~ Spiral ~

Advantages
- No static number of iteration
- High amount of risk analysis. 
- Good for large and mission-critical projects.
- Software is produced early in the software life cycle.
Disadvantages
- Can be a costly model to use.
- Risk analysis requires highly specific expertise.
- Project’s success is highly dependent on the risk analysis phase.
- Doesn’t work well for smaller projects.

~ Concurrent Model ~

Advantage 
- Easy to implement concurrent access if that run for a long time.
- Very dynamic and encourage innovation  by development.
- Able to access the progress of the project by looking at the state of the project. 
Disadvantage 
- Multiple team and module is very difficult.
- Managing this kind of process model is challenging.


Selecting a Process Model


Factor to consider


The characteristic of the - problems to be solved
                                     - project
                                     - product
   
The project environment in which the software team works. 
                                                           


To downloaded notes (Module2) : http://metalab.uniten.edu.my/~badariah/CSEB233.htm

THEEPA LAKNAKUMARAN (SW086630)