Key term
AQA GCSE Computer Science 8525
Algorithms
Programming
Data Representation
Topic overviewNumber bases and why hexadecimal is usedConverting between binary, decimal and hexadecimalUnits of information: bits, bytes and prefixesBinary addition and binary shiftsCharacter encoding: ASCII and UnicodePixels, bitmaps and colour depthBitmap image file size calculationsDigital sound: sampling rate and sample resolutionData compression: Huffman coding and run-length encoding
Computer Systems
Computer Networks
Cyber Security
Relational Databases and SQL
Ethical, Legal and Environmental Impacts of Digital Technology
Computer Systems
- 6 subtopics
- 18 things to know
- Paper 2
What Computer Systems covers
Computer Systems is examined in Paper 2, Computing concepts. It covers hardware, software and the operating system, logic gates, truth tables and Boolean expressions, programming languages and translators, the CPU and the fetch-execute cycle, types of memory and embedded systems and secondary storage and cloud storage.
Where it is assessed
Paper 2
Computing concepts, a 1 hour 45 minute paper worth 50% of the GCSE.
Check the AQA specification ↗The 6 subtopics
Each one has its own page.
- Hardware, software and the operating systemHardware and software, system and application software, how an operating system manages the processor, memory, devices, applications and security, and utility programs such as backup.Open →
- Logic gates, truth tables and Boolean expressionsNOT, AND, OR and XOR gates and their symbols, writing and evaluating Boolean expressions, truth tables for three inputs, and building circuits from expressions.Open →
- Programming languages and translatorsHigh-level and low-level languages, machine code and assembly language, the advantages of each, and how assemblers, compilers and interpreters translate code and when to use each.Open →
- The CPU and the fetch-execute cycleThe Von Neumann architecture, the ALU, control unit, clock, registers and buses, how clock speed, cores and cache affect performance, and the fetch, decode and execute stages.Open →
- Types of memory and embedded systemsRAM, ROM, cache and registers, volatile and non-volatile memory, the memory hierarchy from fastest to slowest, and embedded systems such as a washing machine controller.Open →
- Secondary storage and cloud storageWhy secondary storage is needed, how magnetic, optical and solid state drives store data, choosing between them, and the advantages and disadvantages of cloud storage.Open →
What you need to know
Answer each one before you reveal it.
Your recallNot started
Process
How do extra processor cores help, and why is the speed-up often less than expected?
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How are the logic circuit symbols for AND, OR, XOR and NOT told apart?
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Define the term hardware.
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What is a high-level language?
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What is secondary storage?
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Define the term software.
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What does a NOT gate do?
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What is a low-level language?
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What is the Von Neumann architecture?
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What is RAM used for?
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Why is secondary storage needed?
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What is the relationship between hardware and software?
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When does an AND gate output 1?
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Why are most programs written in high-level languages?
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What is the role of main memory in the Von Neumann architecture?
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What is ROM used for?
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How does main memory differ from secondary storage?
Take Computer Systems further
The same content, four other ways.
Commonly confused
Pairs that lose marks when they are blurred together.
RAM vs ROM
RAM: volatile memory holding the programs and data currently in use. ROM: non-volatile memory holding the fixed start-up instructions.
Compiler vs Interpreter
Compiler: a translator that turns a whole high-level program into an executable before it runs. Interpreter: a translator that carries out a high-level program one statement at a time.
High-level language vs Low-level language
High-level language: programming code with English-like keywords that works on many processors. Low-level language: programming code close to the processor's own instructions.
Questions from this topic
Each one with the model answer underneath.
- 1
Define the term hardware.
Model answer
Hardware is the physical parts of a computer system that can be touched. Examples include the CPU, a keyboard and a hard disk drive.
- 2
Define the term software.
Model answer
Software is the programs that run on a computer system. Software is made up of instructions that tell the hardware what to do.
- 3
What is the relationship between hardware and software?
Model answer
Hardware needs software to tell it what to do. Software needs hardware to run on, so neither is useful without the other.
- 4
What is system software?
Model answer
System software controls the hardware and looks after the computer's resources. Application software runs on top of the system software.
- 5
What is application software?
Model answer
Application software is software that lets the user carry out a task. Examples include word processors, web browsers and games.
- 6
Give two examples of system software.
Model answer
An operating system such as Windows is one example of system software. A utility program such as backup software is also system software.
What is inside Levo
Six ways to work the same material.
Computer Systems revision questions
- What does Computer Systems cover in AQA GCSE Computer Science?
- 6 subtopics: hardware, software and the operating system, logic gates, truth tables and boolean expressions, programming languages and translators, the cpu and the fetch-execute cycle, types of memory and embedded systems and secondary storage and cloud storage. Each one has its own page with questions and model answers.
- How is Computer Systems organised?
- By the AQA 8525 specification, subtopic by subtopic, so it matches the order you are taught it in.
Every question in Computer Systems, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
Or £46 a year, about £3.83 a month. Cancel anytime.