1. Methodologies in Computing
By Craig Horsley

2. Waterfall life cycle
The waterfall life cycle is a way of producing a program where you follow steps through to complete the development.
The next step only begins after the previous one is complete. If a problem is identified then the process must either repeat or return to the step just prior, depending on the variant of the cycle being followed.
There isn’t much feedback to the customer until the end of the process.
This cycle was actually presented as an example of a flawed model by the writer Winston W. Royce.

3. PROS:
Each step is carefully reviewed before the next one starts
Everyone works on the same step, reducing miscommunication
CONS:
Little customer feedback
The slowest model
You may be forced to restart if there’s an issue depending on your variant.

4. Agile methology
The agile methodology was derived from the “agile manifesto”
It values “individuals and interactions”, “working software”, “customer collaboration” and “responding to change” over normal conventions of programming.
Rather than a concrete idea, a series of different and slightly distinct methodologies have evolved from it.
The basic idea is that all development stages occur at the same time, and development is seen by the customer: if something is wrong in the final product, it can be rectified in a new build.

5. Extreme programming
Extreme programming is a variation of the agile methodology.
It’s based on 4 simple values: simplicity, communication, feedback and courage.
There are many supporting practices too.
It’s aimed at producing high-quality software quickly and repeatedly.
Customers are very involved, there’s lots of testing and planning involved too, making it an involved process.

6. PROS:
The customer can see and shape the project
Mistakes can be rectified in the next build of the program
CONS:
Everyone working at once means there’s risk of miscommunication
Potentially strict deadlines.

7. Spiral model
The spiral model has four phases: Planning, Risk analysis, Engineering and Evaluation
You repeatedly pass through each stage throughout the process
Software is also produced very early and passes through various iterations.

8. PROS:
Lots of risk analysis: very good for risky projects
Software is produced quickly
You can easily document the process thoroughly
You can add functions later on
CONS:
Can prove costly
If risk analysis goes wrong then this can severely impact the project
Bad for small projects

9. Rapid Application Development
In RAD the parts of a program are all developed in parallel, like mini-projects
The prototype can be quickly assembled and shown to the customer before being redeveloped and updated based on feedback
Prototypes are crucial to this model

10. PROS:
Quick initial customer reviews
Encourages customer feedback
Development time is fast and components can easily be re-used
CONS:
Depends a lot on individual performance due to division of the project
Needs highly skilled developers and designers
Can’t work with smaller projects as it’s expensive