Computers

What Computers covers

Computers is examined in Paper 1, Principles of Computer Science. It covers von Neumann architecture and the fetch-decode-execute cycle, secondary storage: magnetic, optical and solid state, embedded systems, operating systems, utility software and robust software and low-level and high-level languages and translators.

The 6 subtopics

Each one has its own page.

• Von Neumann architecture and the fetch-decode-execute cycleThe stored program concept, main memory, the control unit, ALU, registers and clock, the address, data and control buses, and each stage of the fetch-decode-execute cycle.Open →
• Secondary storage: magnetic, optical and solid stateWhy secondary storage is needed, how magnetic, optical and solid state devices store data, their advantages and disadvantages, and choosing storage for a given job.Open →
• Embedded systemsWhat embedded systems are and how they differ from general-purpose computers, firmware, examples from thermostats, brakes and traffic lights, and the risks of connected devices.Open →
• Operating systemsThe purpose of an operating system, file, process, peripheral and user management, device drivers, file permissions, multitasking on one core, and the user interface.Open →
• Utility software and robust softwareFile repair, backup, compression, defragmentation and anti-malware utilities, robust software and why it matters, and finding vulnerabilities with audit trails and code reviews.Open →
• Low-level and high-level languages and translatorsHigh-level and low-level languages, machine code and assembly language, portability, and how compilers and interpreters translate code and report errors.Open →

What you need to know

Answer each one before you reveal it.

Take Computers further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Compiler vs Interpreter

  Compiler: a translator that turns the whole source program into an executable file before it runs. Interpreter: a translator that converts and runs source code one line at a time.

• Address bus vs Data bus

  Address bus: one-way lines carrying memory locations from the processor to RAM. Data bus: two-way lines carrying instructions and values between the processor and RAM.

• Control unit vs Arithmetic logic unit

  Control unit: the part of the processor that decodes instructions and directs the other components. Arithmetic logic unit: the part of the processor that performs calculations and comparisons.

Questions from this topic

Each one with the model answer underneath.

1. 1

   What is the von Neumann stored program concept?

   Model answer

   Program instructions and the data they use are stored together in the same main memory. The CPU fetches both from memory as it needs them.

2. 2

   What is the role of main memory (RAM) in the fetch-decode-execute cycle?

   Model answer

   RAM holds the instructions and data of the programs currently running. The CPU fetches each instruction from its address in RAM.

3. 3

   Why is RAM described as volatile?

   Model answer

   RAM loses its contents when the power is switched off. Any work not saved to secondary storage is lost.

4. 4

   What does the control unit do?

   Model answer

   The control unit manages the fetch-decode-execute cycle. The control unit sends control signals that direct the other parts of the computer.

5. 5

   What does the arithmetic logic unit (ALU) do?

   Model answer

   The ALU carries out arithmetic such as addition and subtraction. The ALU also performs logical operations and comparisons between values.

6. 6

   What are registers?

   Model answer

   Registers are very small, very fast storage locations inside the CPU. Registers hold the instruction, address or data being worked on at that moment.

What is inside Levo

Six ways to work the same material.

Computers revision questions

What does Computers cover in Edexcel GCSE Computer Science?

6 subtopics: von neumann architecture and the fetch-decode-execute cycle, secondary storage: magnetic, optical and solid state, embedded systems, operating systems, utility software and robust software and low-level and high-level languages and translators. Each one has its own page with questions and model answers.

How is Computers organised?

By the Edexcel 1CP2 specification, subtopic by subtopic, so it matches the order you are taught it in.