# AQA (8525) GCSE Computer Science

## 3.1.1: Representing algorithms

Computational thinking
• Decomposition
• Pattern recognition
• Abstraction
• Algorithms
Flowcharts
• Standard shapes
• Algorithms
Pseudocode
• Syllabus pseudocode

## 3.1.2–3.1.4: Using algorithms

Algorithm efficiency
• Time efficiency
• Space efficiency
Searching algorithms
• Linear search
• Binary search
Sorting algorithms
• Bubble sort
• Merge sort

## 3.2.1–3.2.6: Programming components

Data types
• Character
• String
• Integer
• Real
• Boolean
Variables and constants
• Naming
• Assigning
• Uses
Operators
• Arithmetic
• Boolean
• Relational
Sequence, selection, iteration
• IF
• WHILE
• CASE
• REPEAT
• FOR
• Nesting
Data structures
• List
• Dictionary
• Tuple
Arrays and records
• 1D Array
• 2D Array
• Array operations
• Records

## 3.2.7–3.2.10: Processes

File handling
• Open
• Close
• Write
String handling
• Storage
• Search
• Properties
• Type casting
• Character codes
Random number generation
• Random integers
• Python examples
• Uses
Subroutines
• Coding
• Functions
• Scope
• Uses

## 3.2.11–3.2.13: Writing programs

Structured programming
• Planning
• Iteration
• Subroutines and Functions
• Modules & Scope
• Python Examples
Validation and authentication
• Length check
• Range check
• Authentication
• Test Data
• Python Examples
Programming languages
• Machine code
• Low Level
• High level
• Translators, Assemblers
• Compiler, Interpreters

## 3.3.1–3.3.4: Representing numbers

Binary and denary
• Number systems
• Denary to Binary
• Binary to Denary
• Binary Shift
• Uses
• Denary to Hex
• Hex to Denary
• Hex to Binary
• Binary to Hex
Units and prefixes
• Bit, Byte, Nibble
• Kilobyte to Petabyte

## 3.3.5–3.3.7: Creating files

Character sets
• ASCII
• Extended ASCII
• Character Sets
• Unicode
Images
• Pixels
• Grayscale
• Colour Depth
• Files size
Audio
• Sampling
• Sampling frequency
• Bit Depth, Bit Rate
• Channels

## 3.3.8: Compression

Compression
• Lossy compression
• Lossless compression
• Dictionary compression
• Images, Video, Music
Huffman encoding
• Binary Tree
• The concept of it
• Encoding
Run-length encoding
• RLE data format
• RLE & Images
• RLE & Text

## 3.4.1: Hardware and software

Introduction to computer systems
• Computer System
• Hardware
• Software

## 3.4.2: Boolean logic

Boolean logic
• Logic gates
• Logic circuits
• Truth tables

## 3.4.3: Software classification

Software types
• System Software
• Application Software
Operating systems
• Purpose
• Kernel
• User Interface
• Device Drivers

## 3.4.4a: Systems architecture: the CPU

CPU architecture
• What is the CPU?
• ALU, Control Unit
• Clock, Buses
• Von Neumann
CPU performance
• Cache
• Cores
• Overclocking
• Parallel processing
Fetch-Execute cycle
• Hardware used
• Steps in the cycle

## 3.4.4b: Systems architecture: Memory and storage

Main memory
• RAM Random Access
• DRAM and SRAM
Secondary storage
• Magnetic
• Optical
• Solid State
• Cloud
Embedded systems
• Definition
• Sensors
• Analog-Digital converter
• Actuators

## 3.5.1: Networks

Network scale
• Personal Area Networks
• Local Area Networks at home
• Local Area Networks in business
• Wide Area Networks
Network types and shapes
• Wired, Wireless networks
• Star, Bus topology
• Star & Bus animations
• Network Builder
Network protocols
• TCP/IP and UDP
• HTTP and HTTPs
• FTP, Ethernet, Wi-Fi
• Email Protocols
Network security
• Importance of security
• Authentication methods
• Encryption
• Firewalls
• MAC filtering
Four layer model
• Application Layer
• Transport Layer
• Network Layer

## 3.6.1: Cyber security threats

Introduction to cyber-security
• What is it
• Why is it important
• Malicious code
• Social engineering
• Prevention
Penetration testing
• White box testing
• Black box testing
Social engineering
• What is social engineering?
• Phishing
• Pharming
• Blagging
• Other social attacks
Malware
• Viruses and Worms
• Browser malware
• Other malware types

## 3.6.2: Preventing cyber-threats

Authentication
• Typical threats
• Biometric authentication
• Email confirmation

Databases
• Definition
• Flat-file
• Relational
• Management

## 3.8.1: Societal impact

Ethics
• Internet
• Social media
• Digital divide
• Whistleblowing
• Self driving cars
• Genetic screening
• Drone use
Culture
• Anonymity
• Citizen Journalism
• Military Drones
• Health & Technology
• Social Network Impacts
Legislation
• Data Protection Act
• Computer Misuse Act
• Freedom of Information Act
The Environment
• E-Waste
• Sustainability
• Recycling
• Energy use
• Data Centres
• Monitoring
• Stakeholders
Open source software
• Open Source
• Closed Source
• Creative Commons
Privacy
• DNA profiling
• ID Cards
• CCTV
• Tracking
• Personal Data
• Stakeholders