The stages of the systems development lifecycle - analysis, design, implementation, testing, installation and maintenance - and the purpose of a structured approach.

What this dot point is asking

CCEA wants you to describe the systems development lifecycle (SDLC): the ordered stages used to build an information system, what each stage does, the deliverables it produces, and why a structured approach is used. You must distinguish analysis (what the system must do) from design (how it will do it), and know that maintenance continues after installation. This frames the whole A2 1 unit and the A2 2 project, so the stages are examined directly.

The answer

What the lifecycle is and why it exists

Without a structured lifecycle, projects risk building the wrong thing, discovering faults late (when they are expensive to fix), and running over time and budget.

The stages

Analysis versus design, and maintenance

The crucial contrast is what versus how: analysis defines what the system must do (the requirements), while design plans how it will do it (the technical solution). Doing analysis first prevents building a system that does not meet the real need.

Maintenance continues for the system's working life and takes three forms: corrective (fixing faults found in use), adaptive (changing the system to suit a new environment, such as new hardware, software or legislation) and perfective (improving performance or adding enhancements).

Worked example: ordering the lifecycle for a new booking system

Examples in context

Example 1. A library management system. Analysis gathers requirements from librarians (issue, return, reserve, fine). Design specifies the member and loan tables, the screens and the overdue-fine algorithm. Implementation and testing build and verify it, installation converts the catalogue and trains staff, and maintenance later adds an e-book module (perfective) and adapts to a new barcode scanner (adaptive). The ordered stages keep a complex project on track.

Example 2. Skipping analysis goes wrong. A team that jumps straight to coding a stock system without analysis builds fast but discovers, at testing, that it cannot handle returns, a requirement nobody captured. Reworking the design and code late costs far more than the analysis that would have surfaced the requirement at the start, illustrating why the lifecycle front-loads understanding.

Try this

Q1. State the purpose of the analysis stage of the SDLC. [2 marks]

• Cue. To investigate the current system and gather and define the requirements (what the new system must do), producing a requirements specification.

Q2. Name the three types of maintenance. [3 marks]

• Cue. Corrective (fixing faults), adaptive (changing to suit a new environment) and perfective (improving or enhancing).

Q3. State the key difference between the analysis and design stages. [1 mark]

• Cue. Analysis defines what the system must do (requirements); design plans how it will do it (the technical solution).