AQA GCSE Computer Science scheme of work

Lessons

1. The purpose of the CPU
2. CPU components
3. The clock and the buses
4. Main memory and the Fetch-Execute cycle
5. CPU performance
6. Embedded systems
7. Bringing it together

By the end, pupils can

• State the purpose of the CPU: to fetch, decode and execute instructions.
• Describe the function of the ALU, control unit, cache and registers.
• Describe the role of the clock and of the address, data and control buses.
• Describe the role of main memory and why programs are copied into it to run.
• Explain the role of main memory in each stage of the Fetch-Execute cycle.

Lessons

1. Main memory: RAM and ROM
2. Cache and registers
3. Main memory and secondary storage
4. Solid state and magnetic storage
5. Cloud storage
6. Bringing it together

By the end, pupils can

• Define main memory and explain the terms volatile and non-volatile.
• Describe what RAM and ROM are used for and state the differences between them.
• Explain what cache and registers are used for and why each is needed.
• Compare main memory with secondary storage and explain why secondary storage is required.
• Describe how magnetic and solid state storage operate.

Lessons

1. Number bases
2. Converting between number bases
3. Units of information
4. Binary arithmetic
5. Character encoding
6. Representing images
7. Representing sound
8. Data compression
9. Bringing it together

By the end, pupils can

• Describe decimal, binary and hexadecimal and explain why hexadecimal is often used in computer science.
• Convert whole numbers from 0 to 255 between binary, decimal and hexadecimal in both directions.
• Use bits, bytes and the prefixes kilo, mega, giga and tera to convert and compare quantities of data.
• Add up to three 8-bit binary numbers and apply logical binary shifts to multiply and divide by powers of 2.
• Describe 7-bit ASCII and Unicode and convert between characters and character codes.

Lessons

1. Algorithms, decomposition and abstraction
2. Representing algorithms
3. Trace tables and the purpose of algorithms
4. Efficiency of algorithms
5. Searching algorithms
6. Sorting algorithms
7. Bringing it together

By the end, pupils can

• Define algorithm, decomposition and abstraction, and explain how an algorithm differs from a program.
• Represent simple algorithms using AQA pseudo-code, flowcharts and program code.
• Identify the inputs, processing and outputs of a simple algorithm.
• Use trace tables and visual inspection to work out how a simple algorithm works and its purpose.
• Explain why more than one algorithm can solve a problem and compare algorithms by time efficiency.

Lessons

1. Data types, variables and input/output
2. Arithmetic, relational and Boolean operations
3. Selection and iteration
4. Data structures
5. String handling and random numbers
6. Subroutines and structured programming
7. Robust and secure programming
8. Bringing it together

By the end, pupils can

• Choose suitable data types and use variables, constants, assignment, input and output.
• Use arithmetic operations including DIV and MOD, relational operators and NOT, AND and OR.
• Write and trace selection, definite and indefinite iteration, and nested structures.
• Use one- and two-dimensional arrays and records to store related data.
• Apply string handling operations, type conversions and random number generation.

Lessons

1. NOT, AND and OR gates
2. The XOR gate and Boolean expressions
3. Truth tables for logic circuits
4. From circuit to Boolean expression
5. From Boolean expression to circuit
6. Bringing it together

By the end, pupils can

• State the truth tables for the NOT, AND, OR and XOR logic gates.
• Recognise and draw the standard symbols for NOT, AND, OR and XOR gates.
• Write and evaluate Boolean expressions using AQA notation (. + overbar ⊕).
• Construct truth tables with up to three inputs for simple logic circuits, using working columns.
• Interpret truth tables to describe when a circuit’s output is 1.

Lessons

1. Hardware and software
2. System software and application software
3. The operating system
4. Utility programs
5. Low-level and high-level languages
6. Translators
7. Bringing it together

By the end, pupils can

• Define hardware and software and explain the relationship between them.
• Explain the difference between system software and application software, giving examples of each.
• Describe how the operating system manages the processor, memory, I/O devices, applications and security.
• Explain the need for, and functions of, backup, anti-malware, defragmentation, compression and encryption utilities.
• Describe machine code and assembly language and explain why both are low-level and processor-specific.

Lessons

1. Networks and network types
2. Wired and wireless networks
3. Network protocols
4. Network security
5. The TCP/IP model
6. Bringing it together

By the end, pupils can

• Define a computer network and discuss its advantages and disadvantages.
• Describe PAN, LAN and WAN networks and give an example of each.
• Compare wired and wireless networks, and choose between copper and fibre optic cable.
• Explain the purpose of the network protocols TCP, IP, HTTP, HTTPS, SMTP and IMAP.
• Explain how authentication, encryption, firewalls and MAC address filtering work together to secure a network.

Lessons

1. Fundamentals of cyber security
2. Social engineering
3. Malicious code (malware)
4. Pharming and other threats
5. Penetration testing
6. Detecting and preventing threats
7. Bringing it together

By the end, pupils can

• Define cyber security and describe its main purposes.
• Describe blagging, phishing and shouldering and explain how to protect against social engineering.
• Describe how computer viruses, trojans and spyware work and how to protect against malware.
• Explain pharming and the threats posed by weak and default passwords, misconfigured access rights, removable media and unpatched or outdated software.
• Explain the purpose of penetration testing and compare tests that simulate a malicious insider and an external attacker.

Lessons

1. What is a database?
2. Keys and relational databases
3. Redundancy and inconsistency
4. Retrieving data with SELECT
5. Sorting and querying two tables
6. Changing data: INSERT, UPDATE and DELETE
7. Bringing it together

By the end, pupils can

• Explain what a database and a relational database are.
• Identify tables, records and fields, and choose a suitable data type for each field.
• Describe the purpose of a primary key and choose a suitable primary key for a table.
• Explain how a foreign key links two tables in a relational database.
• Explain how relational databases reduce data redundancy and data inconsistency.

Lessons

1. Ethical, legal and environmental impacts
2. Data privacy
3. Hacking and cyber security
4. Mobile technologies, wireless networking and cloud storage
5. Wearable technologies and computer-based implants
6. Autonomous vehicles
7. Environmental impacts
8. Bringing it together

By the end, pupils can

• Explain the difference between ethical, legal and environmental impacts and identify the stakeholders affected.
• Explain data privacy issues and discuss the debate between citizens’ privacy and governments’ need for security.
• Explain what hacking is and its ethical and legal impacts on individuals, organisations and society.
• Evaluate the benefits and risks of mobile technologies, wireless networking and cloud storage.
• Discuss the benefits, risks and ethical questions raised by wearable technologies and computer-based implants.