Know and understand the need to identify the inputs, outputs and processing of the current system, problems with the current system, the user and information requirements for the new system

Published by Patrick Mutisya · 14 days ago

Cambridge IGCSE ICT 0417 – The Systems Life Cycle

7. The Systems Life Cycle

1. Why analyse the current system?

Before a new computer‑based solution can be designed, the existing (or “manual”) system must be understood. This analysis provides the basis for:

  • Identifying what works well and what does not.

  • Determining the exact data that must be captured (inputs) and the results required (outputs).

  • Establishing the processing steps that transform inputs into outputs.

  • Gathering the user’s expectations and the information that the new system must provide.

2. Identifying inputs, processing and outputs of the current system

Use the following table to record each component of the existing system.

ComponentExamplesComments / Issues
InputsPaper forms, telephone calls, sensor readings, manual calculationse.g., data entry errors, missing fields
ProcessingSorting files, calculating totals by hand, applying business rules on papere.g., time‑consuming, inconsistent application of rules
OutputsPrinted reports, handwritten invoices, verbal feedbacke.g., delayed distribution, limited accessibility

3. Problems with the current system

Common problems fall into three categories: technical, organisational and human.

  • Technical problems – data loss, lack of backup, poor data integrity.

  • Organisational problems – duplicated work, bottlenecks, lack of standard procedures.

  • Human problems – user fatigue, high error rates, resistance to change.

4. User requirements for the new system

These are statements of what the users need the system to do. They should be written in plain language and be testable.

  • The system must allow data entry via a keyboard and touchscreen.

  • Users must be able to retrieve a report within 5 seconds of request.

  • Access levels must be defined so that only managers can delete records.

  • The interface should be intuitive, requiring no more than one hour of training.

5. Information requirements for the new system

These describe the type, format and quality of data the system must handle.

  • Data types: text, numeric, dates, Boolean flags.

  • Data format: e.g., dates in YYYY‑MM‑DD format, currency with two decimal places.

  • Data quality: mandatory fields, validation rules (e.g., \$0 \leq \text{Quantity} \leq 10\,000\$), uniqueness constraints.

  • Reporting needs: summary totals, trend graphs, drill‑down details.

6. Checklist for the analysis stage

TaskCompleted?Notes
Document all current inputs, processing steps and outputs
Identify and prioritise problems with the existing system
Gather user requirements through interviews/questionnaires
Define information requirements (data types, validation, reporting)
Obtain sign‑off from key stakeholders

Suggested diagram: A flow diagram showing the three stages – Input → Processing → Output – of the current system, linked to a problem list and the corresponding user/information requirements for the new system.

7. Summary

Understanding the current system’s inputs, processing and outputs is the foundation for a successful redesign. By clearly documenting problems and capturing both user and information requirements, the new system can be built to meet real needs, improve efficiency and reduce errors.