Unit 4 Digital Data
Binary and hexadecimal representation, storage units, character encoding, Boolean data, compression and the accuracy and suitability of data.
How to study for CCEA GCSE Digital Technology
Connect precise digital concepts to scenario evidence, design decisions, testing and evaluation, then rehearse the controlled-practice lifecycle under your centre's current CCEA instructions.
Core concepts
Concept 1
Digital systems encode numbers, text, images and logical states in binary patterns whose meaning depends on the chosen representation.
Exam cue: State the base and place values before converting a number.
Concept 2
Hexadecimal is a compact representation of binary data, while storage calculations require consistent units and explicit conversion steps.
Exam cue: Show units at every stage of a storage calculation.
Concept 3
Compression trades storage or transmission cost against processing and, for lossy methods, fidelity to the original data.
Exam cue: Choose lossless or lossy compression by explaining what information may safely be discarded.
Risk pitfalls and guardrails
Reading a binary value as decimal digits.
Guardrail: Keep to Northern Ireland CCEA scope, never add the weights of both routes, and distinguish a digital concept from unsupported product or technology claims.
Mixing bits and bytes or decimal and binary storage conventions mid-calculation.
Guardrail: Keep to Northern Ireland CCEA scope, never add the weights of both routes, and distinguish a digital concept from unsupported product or technology claims.
Assuming every compressed file can be reconstructed exactly.
Guardrail: Keep to Northern Ireland CCEA scope, never add the weights of both routes, and distinguish a digital concept from unsupported product or technology claims.
Memory anchors
Bit
One binary digit with a value of zero or one.
Byte
A group of eight bits.
Hexadecimal
Base sixteen notation that maps compactly to groups of four bits.
Character encoding
A mapping between characters and stored numeric codes.
Lossless compression
Compression that permits exact reconstruction of the original data.
Lossy compression
Compression that permanently removes selected information to reduce size.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
[Programming route] Convert binary 110010 to denary.
Which binary represents denary 25?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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