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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 659 exam-style questions, each with its mark scheme and example answers. Print it, or answer it on paper and then open the mark schemes. Or browse the questions by topic.

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4 questions · 12 marks

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1Short recall2 marksTopologies Swap Remove

Mesh is a type of network topology.

State two characteristics of a mesh topology.

[2 marks]
Mark scheme

Award one mark for any of the following up to a maximum of two marks:

  • Each node/device has multiple direct connections to other nodes/devices (in a full mesh, every node is connected directly to every other node) (1)
  • There is no central device/switch (1)
  • Nodes act as routers/relay data for other nodes / data can take multiple/different routes to its destination / data can still be sent if a connection/node fails (1)
  • More connections/cables are needed as the number of nodes increases (1)
  • The network can be expanded without disrupting existing devices (1)

Allow answers that refer to full or partial mesh.

Allow 'more connections/cables are needed' and 'can be expanded' as characteristics (they may be described as advantages or disadvantages).

Do not accept 'more secure' or 'no collisions' without qualification.

Do not accept 'fast' or 'reliable' without qualification.

Do not accept all devices connect to one main cable (this describes a bus topology).

Do not accept it uses a central switch/hub or data is sent through a central hub (this describes a star topology).

Do not accept 'expensive' without qualification (e.g. because more cables/connections are needed).

Example answers and how they were marked
Full marks2/2

Each device is connected to several other devices, and data can be sent along more than one route.

Why: Multiple direct connections (1) and data can take multiple routes (1).

Some marks1/2

There is no central switch.

Why: No central device credited (1), but only one characteristic given.

No marks0/2

Data is sent through a central hub.

Why: Misconception: this describes a star topology, not a mesh topology.

2Short recall2 marksCompression Swap Remove

Files can be compressed before they are stored.

Define the term lossless compression.

[2 marks]
Mark scheme

Award one mark for any of the following up to a maximum of two marks:

  • Reduces/makes the size of a file smaller (1)
  • No data is lost/removed (during compression) (1)
  • The original file/data can be recreated/restored exactly (1)

Allow 'the compressed file takes up less storage space' for the first mark.

The second and third bullets are two ways of making the same point: award a maximum of one mark for them, so a response that says no data is lost and that the original file can be restored, but does not say the file is smaller, scores one mark.

Do not accept descriptions of lossy compression, e.g. 'it removes data that is not needed to make the file smaller'.

Ignore reference to download/transmission times, bandwidth and streaming, as these are benefits of compression and not part of the definition.

Example answers and how they were marked
Full marks2/2

Lossless compression reduces the size of a file without permanently removing any data, so the original file can be restored exactly.

Why: Reduces the size of a file (1) and no data is lost, so the original can be restored exactly (1); maximum of two marks reached.

Some marks1/2

It makes a file smaller so it downloads more quickly.

Why: Reduces the size of a file (1); the faster download is ignored as a benefit, not part of the definition.

No marks0/2

It removes data that is not needed to make the file smaller.

Why: Describes lossy compression, which the do-not-accept line rules out, so the mention of making the file smaller is not credited.

3Describe2 marksUser Management Swap Remove

A computer can be used by more than one person.

Describe how an operating system uses access rights to protect each user's files.

[2 marks]
Mark scheme

Award up to two marks for a linked description such as:

  • Each user/file is given permissions/access rights (1) so other users cannot read/write/open/change that user's files (1)
  • A user may be given read-only/read access to a file (1) so they cannot edit/delete/change it (1)
  • Each file is given permissions/access rights for different users (1) so the operating system allows/refuses access depending on which user is logged in (1)
  • The operating system checks a user's permissions/access rights when a file is opened (1) so a user with read-only/read access cannot save/delete changes (1)

Do not accept responses about asking for a password/username, as this checks who the user is, not what they are allowed to do.

Do not accept 'files are protected/safe' or 'access rights protect files' without saying how access is limited (e.g. read-only access, permissions for different users).

Example answers and how they were marked
Full marks2/2

A user can be given read-only access to a file, so they can open it but cannot edit or delete it.

Why: Read-only/read access point (1) and linked development that the user cannot edit/delete the file (1).

Some marks1/2

A user can be given read-only access to a file.

Why: Read-only/read access point (1); no development saying what this prevents, such as being unable to edit/delete the file (0).

No marks0/2

The operating system asks for the password again before the file opens.

Why: Describes asking for a password, which checks who the user is, not access rights to the file; no creditworthy point.

4Discuss6 marksFetch Decode Execute Cycle Swap Remove

A small robotics company is designing a new robot. The robot's computer uses von Neumann architecture. The engineers are explaining how programs are stored and run.

Discuss how the von Neumann stored program concept and main memory (RAM) are used during the fetch-decode-execute cycle.

Your answer should include:

  • what is meant by the stored program concept
  • the role of RAM in the cycle
  • why the stored program concept is useful.
[6 marks]
Mark scheme

Indicative content

Stored program concept

  • Instructions and data are stored together in the same main memory (RAM).
  • Instructions are fetched one at a time from memory and executed in sequence.
  • The program can be changed by loading different instructions into RAM.
  • The CPU can only execute instructions that are in main memory.

Role of RAM

  • RAM holds the program instructions and the data being used.
  • The address of the next instruction is held in the program counter (PC).
  • The instruction is fetched from RAM using the address bus.
  • The data bus carries the instruction from RAM to the CPU.
  • RAM is volatile, so programs are lost when power is off.
  • RAM is directly accessible by the CPU, unlike secondary storage.

Benefits

  • The same hardware can run many different programs.
  • Programs can be loaded and changed quickly.
  • No need to rewire the computer for a new task.
  • Makes general-purpose computers possible.

Levels

  • Level 0 (0 marks): No rewardable content.
  • Level 1 (1–2 marks): Basic, independent points are made, showing elements of understanding of key concepts/principles of computer science. (AO1) The discussion will contain basic information with little linkage between points made or application to the context. (AO2)
  • Level 2 (3–4 marks): Demonstrates adequate understanding of key concepts/principles of computer science. (AO1) The discussion shows some linkages and lines of reasoning with some structure and application to the context. (AO2)
  • Level 3 (5–6 marks): Demonstrates comprehensive understanding of key concepts/principles of computer science to support the discussion being presented. (AO1) The discussion is well developed, with sustained lines of reasoning that are coherent and logically structured, and which clearly apply to the context. (AO2)
Example answers and how they were marked
Full marks6/6

The von Neumann stored program concept means that both the program instructions and the data are stored together in the same main memory, RAM. During the fetch-decode-execute cycle, the CPU fetches an instruction from RAM, decodes it in the control unit, and then executes it. The program counter holds the address of the next instruction, and this address is sent along the address bus to RAM. RAM then returns the instruction along the data bus to the CPU. RAM is volatile, so it only holds the program while the robot is powered on. The stored program concept is useful because the robot's computer can run different programs without changing any hardware; new instructions can simply be loaded into RAM. This makes the computer general-purpose and flexible.

Why: Comprehensive understanding: defines stored program concept, explains RAM role with PC, address bus and data bus, applies to robot, and gives benefits. Sustained lines of reasoning. Level 3.

Some marks3/6

The stored program concept is when instructions and data are stored in RAM. The CPU fetches instructions from RAM. The program counter keeps the address of the next instruction. RAM holds the program. The benefit is that you can change the program without rewiring the computer.

Why: Adequate understanding: correct basic points about stored program concept and RAM, with some linkage, but little development or application to the robot's fetch-decode-execute cycle. Level 2.

Some marks1/6

The von Neumann stored program concept is that the CPU uses RAM to store the program. The fetch-decode-execute cycle fetches, decodes and executes. RAM is random access memory. The benefit is that it is fast.

Why: Basic independent points only; no real linkage or application to the robot. Level 1.

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5.3 Cybersecurity

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