Computer Systems | AQA GCSE Computer Science (8525)

Computer Systems

  • 95 questions
  • 6 subtopics
  • Paper 2
  • Paper 2

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.

Sample questions from Computer Systems

Answer each one closed book first, then open the answer.

  1. Hardware, software and the operating system

    Give two examples of system software.

    Show the answer
    An operating system such as Windows is one example of system software. A utility program such as backup software is also system software.
  2. Hardware, software and the operating system

    How does an operating system manage applications?

    Show the answer
    The OS loads applications into memory and starts them running. The OS also closes applications and handles their requests for resources such as files.
  3. Logic gates, truth tables and Boolean expressions

    Which symbols represent AND, OR, XOR and NOT in a Boolean expression?

    Show the answer
    A dot (written . or ·) represents AND and a plus sign represents OR. The symbol ⊕ represents XOR, and a bar over a term represents NOT.
  4. Logic gates, truth tables and Boolean expressions

    How many rows does a truth table need for a circuit with three inputs?

    Show the answer
    A truth table for three inputs needs 8 rows. Each extra input doubles the number of rows, as 2³ = 8.
  5. Programming languages and translators

    What is assembly language?

    Show the answer
    Assembly language is a low-level language that uses short mnemonics such as ADD and SUB. Each mnemonic stands for one machine code instruction.
  6. Programming languages and translators

    What does an assembler do?

    Show the answer
    An assembler translates assembly language into machine code. Each line of assembly language becomes exactly one machine code instruction.
  7. The CPU and the fetch-execute cycle

    What is a register?

    Show the answer
    A register is a very small, very fast memory location inside the CPU. Registers hold the instruction or data currently being worked on.
  8. The CPU and the fetch-execute cycle

    How does a larger cache affect CPU performance?

    Show the answer
    A larger cache can hold more of the instructions and data the CPU uses often. The CPU goes to slower main memory less often, so programs run faster.

The 6 subtopics

One subtopic is one session. Work down the list.

Subtopic What it covers Questions
Hardware, software and the operating system Hardware and software, system and application software, how an operating system manages the processor, memory, devices, applications and security, and utility programs such as backup. 16
Logic gates, truth tables and Boolean expressions NOT, AND, OR and XOR gates and their symbols, writing and evaluating Boolean expressions, truth tables for three inputs, and building circuits from expressions. 16
Programming languages and translators High-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. 16
The CPU and the fetch-execute cycle The 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. 16
Types of memory and embedded systems RAM, 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. 16
Secondary storage and cloud storage Why secondary storage is needed, how magnetic, optical and solid state drives store data, choosing between them, and the advantages and disadvantages of cloud storage. 15
Computer Systems is 95 of the 664 questions in the guide.Get the guide, £7

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

  1. Step 1 · Closed book

    Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.

  2. Step 2 · Open book

    Go back to the top. Read each printed answer and write it out in full, including the ones you had right.

  3. Step 3 · Closed book again

    Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.

Nearby topics

All 8 topics Guide overview

AQA GCSE Computer Science Active Recall Guide

Every topic, not just this one. 664 questions with their answers.

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