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System Development

Introduction to System Development Lifecycle
1. System Development Model
Software development has hit something of a crisis - we fail to deliver software that meets user expectation. However by employing disciplined techniques throughout the development of software and by employing a philosophy of co-ordination, control and management through out the development lifecycle of a software project enhanced standards may be achieved.
The aim is to provide discipline to the development of software - a structured framework against which development takes place is advocated.
A model of the process of systems development is used by organisations to describe their approach to producing computer systems. Traditionally this has been a staged (or phased) approach, known as the System Life Cycle or System Development Life Cycle (SDLC).
An example of a SDLC is given below:
STAGE TASK OUTCOMES
Problem Definition Establish what the problem is Statement of requirements
Feasibility Study Establish scope & objectives;determine whether project is viable Feasibility study report
Analysis Define what constitutes a solution to the problem Logical model of the solution
Outline Design Determine ways of solving the problem and choose one Costing and high level design of the system
Detailed Design Specify how the system will be implemented System specifications
Implementation Write the program & procedures;Install & test system Working system & documentation
Maintenance Provide support & enhancements Working system

2. Classical Waterfall
The lifecycle approach is derived from the waterfall model of system development described by Royce in 1970, a simplified version of which is given below:

Classic System Development Lifecycle - Version 1
There are now many variations on the theme of the waterfall model, an alternative is presented below:

Classic System Development Lifecycle - Version 2
Feasibility: Is the project technically, operationally, financially and...