The use of variables, constants, operators, inputs, outputs and assignments
The use of the three basic programming constructs used to control the flow of a program:

Sequence
Selection
Iteration (count- and condition-controlled loops)

The common arithmetic operators
The common Boolean operators AND, OR and NOT

The use of data types:

Integer
Real
Boolean
Character and string
Casting

Standard searching algorithms:

Binary search
Linear search

Standard sorting algorithms:

Bubble sort
Merge sort
Insertion sort

The use of basic string manipulation
The use of basic file handling operations:

Open
Read
Write
Close

The use of records to store data
The use of SQL to search for data
The use of arrays (or equivalent) when solving problems, including both one-dimensional (1D) and two-dimensional arrays (2D)
How to use sub programs (functions and procedures) to produce structured code
Random number generation

Characteristics and purpose of different levels of programming language:

High-level languages
Low-level languages

The purpose of translators
The characteristics of a compiler and an interpreter

Common tools and facilities available in an Integrated Development Environment (IDE):

Editors
Error diagnostics
Run-time environment
Translators

Principles of computational thinking:

Abstraction
Decomposition
Algorithmic thinking

Identify the inputs, processes, and outputs for a problem
Structure diagrams
Create, interpret, correct, complete, and refine algorithms using:

Pseudocode
Flowcharts
Reference language/high-level programming language

Identify common errors
Trace tables

Standard searching algorithms:

Binary search
Linear search

Standard sorting algorithms:

Bubble sort
Merge sort
Insertion sort

Simple logic diagrams using the operators AND, OR and NOT
Truth tables
Combining Boolean operators using AND, OR and NOT
Applying logical operators in truth tables to solve problems

Defensive design considerations:

Anticipating misuse
Authentication

Input validation
Maintainability:

Use of sub programs
Naming conventions
Indentation
Commenting

The purpose of testing
Types of testing:

Iterative
Final/terminal

Identify syntax and logic errors
Selecting and using suitable test data:

Normal
Boundary
Invalid/Erroneous

Refining algorithms

Impacts of digital technology on wider society including:

Ethical issues
Legal issues
Cultural issues
Environmental issues
Privacy issues

Legislation relevant to Computer Science:

The Data Protection Act 2018
Computer Misuse Act 1990
Copyright Designs and Patents Act 1988
Software licences (i.e. open source and proprietary)

The purpose and functionality of operating systems:

User interface
Memory management and multitasking
Peripheral management and drivers
User management
File management

The purpose and functionality of utility software
Utility system software

Encryption software
Defragmentation
Data compression

Forms of attack:

Malware
Social engineering, e.g. phishing, people as the ‘weak point’
Brute-force attacks
Denial of service attacks
Data interception and theft
The concept of SQL injection

Common prevention methods:

Penetration testing
Anti-malware software
Firewalls
User access levels
Passwords
Encryption
Physical security

Types of network:

LAN (Local Area Network)
WAN (Wide Area Network)

Factors that affect the performance of networks
The different roles of computers in a client-server and a peer-topeer network
The hardware needed to connect stand-alone computers into a Local Area Network:

Wireless access points
Routers
Switches
NIC (Network Interface Controller/Card)
Transmission media

The Internet as a worldwide collection of computer networks:

DNS (Domain Name Server)
Hosting
The Cloud
Web servers and clients

Star and Mesh network topologies

Modes of connection:

Wired
Ethernet

Wireless

Wi-Fi
Bluetooth

Encryption
IP addressing and MAC addressing
Standards
Common protocols including:

TCP/IP (Transmission Control Protocol/Internet Protocol)
HTTP (Hyper Text Transfer Protocol)
HTTPS (Hyper Text Transfer Protocol Secure)
FTP (File Transfer Protocol)
POP (Post Office Protocol)
IMAP (Internet Message Access Protocol)
SMTP (Simple Mail Transfer Protocol)

The concept of layers

The need for primary storage
The difference between RAM and ROM
The purpose of ROM in a computer system
The purpose of RAM in a computer system
Virtual memory

The need for secondary storage
Common types of storage:

Optical
Magnetic
Solid state

Suitable storage devices and storage media for a given application
The advantages and disadvantages of different storage devices and storage media relating to these characteristics:

Capacity
Speed
Portability
Durability
Reliability
Cost

The units of data storage:

Bit
Nibble (4 bits)
Byte (8 bits)
Kilobyte (1,000 bytes or 1 KB)
Megabyte (1,000 KB)
Gigabyte (1,000 MB)
Terabyte (1,000 GB)
Petabyte (1,000 TB)

How data needs to be converted into a binary format to be processed by a computer
Data capacity and calculation of data capacity requirements

Numbers
How to convert positive denary whole numbers to binary numbers (up to and including 8 bits) and vice versa
How to add two binary integers together (up to and including 8 bits) and explain overflow errors which may occur
How to convert positive denary whole numbers into 2-digit hexadecimal numbers and vice versa
How to convert binary integers to their hexadecimal equivalents and vice versa
Binary shifts

Characters
The use of binary codes to represent characters
The term ‘character set’
The relationship between the number of bits per character in a character set, and the number of characters which can be represented, e.g.:

ASCII
Unicode

Images
How an image is represented as a series of pixels, represented in binary
Metadata
The effect of colour depth and resolution on:

The quality of the image
The size of an image file

Sound
How sound can be sampled and stored in digital form
The effect of sample rate, duration and bit depth on:

The playback quality
The size of a sound file

The need for compression
Types of compression:

Lossy
Lossless