Types of system development methods; Prototyping, SDLC. 11 ATAR, 12 GEN
Types of system development methods; Linear (waterfall, cascade), iterative (Rapid Application Development), Ads and disads of each. 12 ATAR

In system development, you find different methods of creating a system. These are the different phases of the work involved.
Each methodology has its own advantages and disadvantages, so its important to pick one that suits your intended outcome.

A prototype is an early model or sample that is used to test functions of a product, to be replicated from or to be learned from.
Prototyping is when we use an early build of a product or system to demonstrate how it will function with live results.
Prototyping is effective as we use a real system for testing as opposed to a theoretical one.
- Advantages:
  - It's easy to see what functionality is missing from the demo
  - It encourages innovation and flexible minds as new ideas can be easily tested
  - It requires validation to work, hence discrepencies can be easily identified
- Disadvantages:
  - Requirements for the product may change significantly after reach build, creating more work
  - Identified non-functional elements may be difficult to document from the demo
  - The client may be unaware or uncertain about what they're looking at or what they want

The System Development Life Cycle (SDLC) is a process commonly used for planning, creating, testing and deploying an information system
It can apply to software, hardware, or a combination of both
The SDLC is defined by a number of clearly grouped activities, known as phases used to develop a finished project or product
Click here to read the page dedicated to the SDLC

11ATAR and 12 GEN STOP HERE

The waterfall / cascade model is a sequential design process in which progress is seen flowing down through the stages, like a waterfall.
Each phase must be completed before the next phase can begin, hence being easy and simple to understand
A review is conducted at the end of each phase to make sure the project is being carried out correctly
- Advantages:
  - Very simple and easy to understand
  - Phases do not overlap, which allows us to prioritize each phase as it happens
  - Great for smaller projects where the requirements are well understood
- Disadvantages:
  - Once in the testing stage, going back is virtually impossible if it was not thought out in the concept stage
  - High amounts of risk and uncertainty due to large amounts of planning
  - Poor model for larger and ongoing projects
  - Not suitable for projects that are likely to change

Rapid Application Development (or RAD) is sometimes used as a general term used to describe an alternative to the waterfall method
It can also be used to describe a methodology created by James Martin
In this methodology, less emphasis is put on planning and more on development
Components (or functions) are developed simultaneously as if they were mini projects
Each component is given a deadline, after which all components are gathered and made in to a working prototype
The prototype is used to assess the user's feedback regarding requirements and expectations from the project
- Advantages:
  - Significantly reduced development time
  - Encourages customer feedback
  - Increases re-usability of components in the system
- Disadvantages:
  - Requires highly skilled designers and developers
  - High dependency on modelling skills
  - Depends on a strong team to identify requirements
When would we use RAD?
- When we need to have a system built in a short time frame (e.g. 2 - 3 months)
- When we have a high availability of designers that are able to design the product, and...
- When our budget is high enough to supply numerous designers and tools needed for automated code generation

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Types of System Development Methods