WJEC A2 · Unit 4

WJEC AS Unit 4: Computer Architecture,
Data & Applications

CPU architecture, parallel processing, assembly language, operating systems, floating point, databases, file organisation, cryptography, and biometrics — all ten Unit 4 topics in one gamified skill path. Earn XP, collect stars, and build your exam readiness topic by topic.

10 topics 40 quiz questions Up to 600 XP Past paper aligned
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Skill Path

Your Unit 4 Learning Journey

Work through each topic in order. Click any unlocked node to launch the quiz. Earn three stars to master a topic and unlock the next one.

Quick Reference

Unit 4 Topic Cards

Past paper mark scheme language, distilled into ten topic cards. Click Quick Quiz on any card to test yourself instantly.

Interactive Tools

Practice the Exam Skills

The Unit 4 paper regularly tests Amdahl’s Law, binary arithmetic, floating point conversion, and number representation. Use these tools to practise the calculations directly.

Amdahl’s Law Calculator

Calculate parallel speedup using Amdahl’s Law. Enter the parallel fraction P (0–1) and number of processors N. Shows step-by-step working just as the exam requires.

Enter a parallel fraction between 0 and 1 and a number of processors, then click Calculate.
Number System Converter

Convert between denary, binary (8-bit), and hexadecimal. Enter a value in any field and convert all three formats at once.

Enter a value in one field above and click Convert.
Two’s Complement

Convert a denary value (positive or negative) to two’s complement binary. Shows every step: positive representation, invert, add 1.

Enter a denary value and click Convert.
Floating Point Converter

Convert a positive denary value to normalised floating point. Specify mantissa and exponent bit widths to match the exam question.

Enter a positive denary value and the mantissa and exponent bit widths.
Binary Addition

Add two denary values using 8-bit binary. Shows full working including carry bits and overflow detection.

Enter two denary values to add them in binary.
Arithmetic Shift

Perform left arithmetic shifts on an 8-bit two’s complement value. Detects overflow and shows the effect on the denary value at each step.

Enter a value and number of left shifts, then click Shift.
Flashcards

Key Unit 4 terms and definitions. Click the card to flip it, then mark whether you know it. Cards you mark as unknown cycle back around. Earn +5 XP for every card you know.

Term — click to reveal
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Definition
Algorithm Tracer

Step Through Past Paper Algorithms

Trace through the assembly code lock, the FDE cycle, Amdahl’s Law, and floating point conversion one step at a time. Earn 10 XP for completing each trace.

Algorithm / Formula
Trace Table
Weekly League

Unit 4 Leaderboard

Earn XP by completing quizzes and using the interactive tools. Your score updates live as you work through the topics.