How is a system designed once its requirements are known, and what design artefacts capture the structure of its data and processing?
System design: designing the inputs, outputs, processing and data structures, the use of flowcharts and pseudocode, the data dictionary, file and interface design, and specifying the hardware and software the proposed system needs.
An Eduqas Component 1 answer on system design: designing inputs, outputs, processing and data structures, using flowcharts and pseudocode, the data dictionary, file and interface design, and specifying the hardware and software the proposed system requires.
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What this dot point is asking
Eduqas wants you to describe how a system is designed once its requirements are known: designing the inputs, outputs, processing and data structures, using flowcharts and pseudocode, building a data dictionary, designing files and interfaces, and specifying the hardware and software the system needs.
The answer
Designing inputs, outputs and processing
The data dictionary and data-structure design
Interface design and the hardware/software specification
Examples in context
Good system design is why a well-built application feels coherent: consistent screens, sensible validation and clear reports all come from the design phase. The data dictionary is the bridge to the database topic (files, tables, keys and normalisation in Component 2), the same field definitions become table columns. For the Eduqas project (Component 3), the design stage is heavily marked: examiners look for input/output designs, a data dictionary, algorithm designs (pseudocode or flowcharts) and a justified hardware/software choice, exactly the artefacts described here.
Try this
Q1. State three pieces of information a data dictionary records about a field. [3 marks]
- Cue. Any three of: field name, data type, length/size, format, validation rules, description, example value.
Q2. Give two principles of good interface design. [2 marks]
- Cue. Any two of: clear consistent layout, logical grouping, meaningful labels, suitable input controls, validation with helpful messages, accessibility.
Q3. What does designing the processing of a system involve? [1 mark]
- Cue. Specifying the algorithms and logic (as flowcharts or pseudocode) that transform inputs into the required outputs.
Exam-style practice questions
Practice questions written in the style of WJEC Eduqas exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Eduqas 20205 marksDescribe what a data dictionary is and the information it records about each data item, and explain why it is a useful design document.Show worked answer →
What it is (up to 2 marks): a data dictionary is a document (or part of the design) that defines every data item used in the system, acting as a central reference for the data.
Information recorded (up to 2 marks): for each item it records the field name, the data type, the field length/size, a description or meaning, the format, validation rules, and an example value.
Usefulness (up to 1 mark): it ensures consistency (everyone uses the same definitions), supports correct database and file design, and makes maintenance easier because the data is documented in one place.
Markers reward the central-definition-of-data description, the typical fields recorded (name, type, length, validation, description), and a reason it is useful (consistency, maintenance, accurate design).
Eduqas 20226 marksA new system requires a data-entry screen for customer orders. Describe the principles of good interface design that should be applied, and explain what is meant by designing the outputs and the processing of a system.Show worked answer →
Interface design principles (up to 3 marks): clear and consistent layout; logical grouping and tab order of fields; meaningful labels and prompts; validation with helpful error messages; suitable input controls (drop-downs for fixed choices); and accessibility (readable fonts, colour contrast).
Designing outputs (up to 2 marks): deciding the content, format and medium of reports and on-screen output so they meet the user's needs, for example an invoice layout or a summary report, with the right fields and totals.
Designing processing (up to 1 mark): specifying the algorithms and logic (often as flowcharts or pseudocode) that transform the inputs into the required outputs.
Markers reward valid interface principles, a correct description of output design (content/format/medium for the user), and processing design (the algorithms/logic).
Related dot points
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Sources & how we know this
- WJEC Eduqas GCE AS/A Level Computer Science specification (from 2015) — Eduqas (2015)