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## Edexcel GCSE Computer Science

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GCSE 9-1 Edexcel Computer Science

### 1: Algorithms

Computational thinking 1.2.1, 1.2.2, 1.2.3, 1.2.4
• Decomposition
• Abstraction
• Pattern recognition
Representing algorithms: Flowcharts 1.1.1, 1.1.2
• Standard Shapes
• Algorithms
Representing algorithms: Pseudocode 1.1.1, 1.1.2
• Syllabus pseudocode
Using algorithms 1.1.3, 1.1.4, 1.1.5
Standard algorithms: Sorting 1.1.8
• Linear search
• Binary Search
Standard algorithms: Searching 1.1.9
• Bubble Sort
• Merge Sort

### 2: Programming

Data types 2.3.1
• Character
• String
• Integer
• Real
• Boolean
Sequence, Selection, Iteration 2.2.1, 2.2.2
• IF
• WHILE
• REPEAT
• FOR
• Nesting
Variables and constants 2.3.4, 2.3.5
• Naming
• Assigning
• Uses
Operators 2.5.1, 2.5.2, 2.5.3
• Arithmetic
• Boolean
• Relational
Data structures 2.2.1, 2.3.2
• One-dimensional arrays
• Two-dimensional arrays
• Records
Strings 2.3.3
• Indexing
• Length
• Traversal
• Concatenation
• Slicing
• Casting and Coercion
Subprograms 2.3.5, 2.6.1, 2.6.2, 2.6.3
• Coding
• Functions
• Scope
• Uses
Inputs and outputs 2.4.1, 2.4.2, 2.4.3
• Presence checks
• Length checks
• Range checks
• Lookup checks
• Writing files
Maintainability 2.1.2
• Whitespace
• Indentation
Types of Errors 2.1.3, 2.1.5
• Logic errors
• Arithmetic order
• Syntax errors
• Run-Time errors
Testing and Evaluating 2.1.4, 2.1.6, 2.1.7
• Test plans
• Test data
• Trace tables
• IDEs
• Evaluating programs

### 3: Data

Binary 3.1.1, 3.1.2, 3.1.3, 3.1.4
• Base systems
• Binary values
• Converting denary to binary
• Converting binary to denary
• Adding binary numbers
• Signed integers
• Shifts
• Uses
• Denary to Hex
• Hex to Denary
• Hex to Binary
• Binary to Hex
Units 3.3.1, 3.3.4
• Bit, Byte, Nibble
• Kilobyte to Petabyte
Representing characters 3.2.1
• ASCII
• Extended ASCII
• Character codes
• Unicode
Representing images 3.2.2
• Pixels
• Grayscale
• Colour Depth
• Files size
Representing sounds 3.2.3
• Sampling
• Sampling frequency
• Bit Depth, Bit Rate
• Channels
Compression 3.2.4, 3.3.2
• Lossy compression
• Lossless compression
• Dictionary compression
• Images,Video,Music
Run-length encoding 3.3.3
• RLE data format
• RLE & Images
• RLE & Text
Encryption and ciphers 3.4.1, 3.4.2
• Purpose
• Symmetric encryption
• Asymmetric encryption
• Caesar Cipher
Databases: Structure 3.5.1, 3.5.2
• Purpose
• Parts
• Flat-file
• Relational
• Keys
Databases: Relationships 3.5.2
• Entities
• Attributes
• E-R diagrams

### 4: Computers

Input-Process-Output 4.1.1
• Input
• Process
• Software
• Output
• Storage
The CPU 4.2.3
• Architecture
• ALU
• Control Unit
• Memory
• Buses
Fetch-Decode-Execute 4.2.3
• Hardware used
• The FDE cycle
Main memory 4.2.2
• RAM Random Access
• DRAM and SRAM
• ROM Read Only
• Cache
Secondary storage 4.2.4, 4.2.5
• Magnetic
• Optical
• Solid State
• Cloud
Embedded systems 4.2.6
• Definition
• Sensors
• Analog-Digital converter
• Actuators
Boolean logic 4.3.1, 4.3.2
• AND, OR, NOT
• Logic Circuits
• Truth Tables
Operating systems 4.4.1
• Purpose
• Kernel
• User Interface
• Device Drivers
Utility software 4.4.2
• Encryption utilities
• Defragmentation utilities
• Compression
• Backup
• Information & diagnostics
Software modelling 4.4.3
Translators and languages 4.5.1, 4.5.2
• Machine code
• Low Level
• High level
• Translators, Assemblers
• Compiler, Interpreters

### 5: Networks

Introduction to networks 5.1.1, 5.1.2,
• What is a network?
• Home networks
• LANs/WANs
• Client-Server/P2P
Network shape 5.1.3, 5.1.4, 5.1.7
• Wired networks
• Wireless networks
• Topologies
Network protocols 5.1.5
• TCP/IP and UDP
• HTTP and HTTPs
• FTP, Ethernet, Wi-Fi
• Email Protocols
TCP/IP layers 5.1.6
• Application Layer
• Transport Layer
• Network Layer
• Data Link Layer
Introduction to Network Security 5.2.1
• Importance of security
• Authentication methods
• Encryption
• Firewalls
• MAC filtering
Cyberattacks 5.2.2, 5.2.3
• Phishing
• Pharming
• Fraud
• Identity theft
Preventing vulnerabilities 5.2.4, 5.2.5
• Software design
• Software testing
• Network testing
• Tools
• Policy
The Internet 5.2.2, 5.3.1, 5.3.2
• ISP
• DNS
• Websites
• Hosting
• The Cloud
• HTML
• HTTP/S

### 6: The Bigger Picture

Environment 6.1.1
• E-waste
• Recycling
• Energy use
• Carbon footprints
Ethics 6.1.2
• Professionalism
• Privacy
• Inclusion
Legislation 6.1.3
• Data Protection Act
• Computer Misuse Act
• Copyright, Designs & Patents Act
• Communication Acts
• Health and Safety
Open/Closed Source 6.1.3
• Open Source
• Closed Source
• Creative Commons