The Systems Development Life Cycle

Purpose of Analysis

Investigating Information System Problems

The main purpose of the analysis stage is to investigate problems within an information system. The solution might involve improvements to the existing system or the creation of a completely new one.

Understanding the Existing System

Systems analysts tasked with investigating the current system may not be familiar with how the organization operates. They need to thoroughly examine the present system to determine user requirements. This involves understanding the purpose of the business or organization and its existing system in terms of inputs, processing, and outputs.

Identifying Constraints

The analysis stage also includes identifying any constraints that might impact the new system. These constraints could include:

• Timescale
• Cost
• Existing hardware and software
• Staff capability

Design

Creating the Systems Specification

The design stage aims to produce a comprehensive Systems Specification document. This document details various design components, including:

• Data capture methods and forms
• Data inputs and outputs (screen designs, report specifications, query designs, storyboards, macros)
• Data processing procedures
• Data structures (database structure, data models, DFDs, normalization)

Development

Building the Software

The development stage focuses on creating the software package required for the information system. This involves writing appropriate programming code or developing the software package's features.

Key Development Aspects

Essential aspects of the development stage include:

• Developing data structures
• Implementing data checking procedures
• Designing the user interface
• Demonstrating effective use of the hardware specification

Prototyping

Refining Requirements

Prototyping involves creating a practical implementation of the system to uncover and refine user requirements.

Types of Prototyping

• Evolutionary Prototyping: Refinements lead to a fully functional system.
• Throw-away Prototyping: Refinements result in a set of user requirements used for further development.

Integration with Other Approaches

The final system can be developed using an alternative approach, such as the Waterfall method, based on the insights gained from prototyping.