Edexcel GCSE Computer Science (1CP2) exam questions

Build a practice paper from 514 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.

Practice paper

5 questions · 17 marks

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1Short recall1 markSecondary Memory Swap Remove

Data is stored on optical discs as pits and lands.

Name the component in an optical disc drive that reads this data.

[1 mark]

Mark scheme

Award one mark for:

Laser (1)

Allow laser beam

Do not accept read/write head

Do not accept pits

Do not accept lands

Do not accept reflective surface

Do not accept magnet/magnetic

Example answers and how they were marked

Full marks1/1

Laser

Why: Laser is the creditworthy answer (1).

No marks0/1

A read/write head

Why: Read/write head is not accepted by the mark scheme; it reads magnetic media, not optical discs, so no marks are awarded.

No marks0/1

Pits and lands

Why: Pits and lands are what the laser reads, not the component that reads the data, so the mark scheme does not accept them.

2Describe2 marksUtility Software Swap Remove

A hard disk can become fragmented as files are saved and deleted.

Describe how disk defragmentation software improves the performance of a hard disk.

[2 marks]

Mark scheme

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

Parts of a file are moved so they are stored together/in consecutive locations (1) so the read/write head has less distance to travel to read the file (1)
Files are rearranged so that each file is stored in one block (1) which reduces the time taken to open/load the file (1)
Free space on the disk is collected into one area (1) so new files can be saved without becoming fragmented (1)
The parts of each fragmented file are put in order (1) so fewer movements of the read/write head are needed to read it (1)

Do not accept responses about compressing files, deleting files or increasing the amount of storage, as these are not what defragmentation software does.

Do not accept 'it makes the disk faster' without saying how the files are changed.

Example answers and how they were marked

Full marks2/2

It moves the parts of a file so they are stored together in consecutive locations (1), so the read/write head does not have to move as far and the file opens more quickly (1).

Why: Linked point (1) and development (1): the file parts are stored together, which reduces read/write head movement.

Some marks1/2

It reorganises the files on the hard disk so that they are stored together.

Why: The point is made (1) but there is no development saying how this improves performance, so the second mark is not awarded.

No marks0/2

It compresses the files so that they take up less space on the disk.

Why: This describes data compression software, which the mark scheme says is not accepted; no creditworthy point is made.

3Explain2 marksPacket Switching Swap Remove

A file is sent across the internet in packets.

Explain why packets from the same file may take different routes.

[2 marks]

Mark scheme

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

Each router chooses the best route at the time (1) so when a route becomes busy/congested or fails, later packets are forwarded along a different path (1)
Routers forward each packet separately (1) so the path a packet takes depends on the traffic conditions when that packet arrives (1)
A router may send a packet to a different next router (1) if its routing table shows a better/less congested route for that packet (1)
Traffic on the internet changes (1) so no single path is kept for the file and each packet can use whichever route is best when it is sent (1)

For both marks, the expansion must follow/associate with the statement.

Allow reference to a routing table, or to how a router decides the route, as part of the linked reason.

Do not accept 'the packets have different IP addresses' because all packets from the same file have the same destination IP address, even though their routes can differ.

Do not accept 'the internet is busy' or 'there is a lot of traffic' on its own without linking this to the router choosing a different route.

Do not accept 'different routers send the packets' on its own without a reason why a different router/route is chosen.

Do not accept an answer that only says the packets take different routes without explaining why.

Example answers and how they were marked

Full marks2/2

Each router chooses the best route at the time, so if one route becomes busy or fails, later packets are sent a different way.

Why: Linked point (1) that each router chooses the best route at the time and reason (1) that a busy or failed route means later packets take a different path.

Some marks1/2

Routers send packets along the least congested route.

Why: States that a router chooses the least congested route (1) but gives no linked reason why this makes the packets from the file take different routes.

No marks0/2

Because each packet is given a different IP address so they go to different places.

Why: Misconception named in the mark scheme: all packets from the same file share the same destination IP address, even though their routes can differ.

4Discuss6 marksUtility Software Swap Remove

A charity has 15 laptops used by staff and volunteers. Staff often download files from the internet and open email attachments. The charity's manager is considering installing anti-malware software on every laptop.

Discuss the use of anti-malware software to protect the charity's computers.

Your answer should consider:

how malware could affect the charity's computers
how anti-malware software finds and deals with malware
what else the charity must do for the anti-malware software to be effective

[6 marks]

Mark scheme

Indicative content

How malware could affect the charity's computers

A virus could damage or delete the charity's files, such as its records of donations.
Spyware could record keystrokes and send staff passwords or personal data to a hacker.
A Trojan horse could hide malicious code inside a useful-looking program that a volunteer downloads, so it is installed without the user knowing.
Malware could spread from one laptop to another through files shared on the charity's network, so more laptops become infected and more files are lost.

How anti-malware software finds and deals with malware

It scans files and compares their code with a database of known malware patterns (signatures) to identify a match.
It can apply rules (heuristics) to decide whether a program is behaving suspiciously.
A suspicious file can be run in a sandbox to see whether its behaviour is malicious.
When malware is found, the file is quarantined so that it cannot run, and it can be deleted.
Downloads and email attachments can be scanned before a member of staff opens them.

What else the charity must do for the anti-malware software to be effective

The database of malware definitions must be kept up to date, or new malware will not be recognised.
Staff and volunteers should be trained not to open unexpected attachments or download from unreliable sites.
Backups are still needed, because anti-malware cannot repair files that malware has already damaged.
Scheduled scans must be allowed to run on all 15 laptops, so that malware is found even if no one opens the file.

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)

Level 3 responses must cover both how malware could affect the computers and how anti-malware software finds or deals with it; a brief deal-with point and an unexplained update point, with no identification method and no effect on the charity's files, are Level 1.

Do not accept anti-malware software described as a firewall, or 'scans files'/'finds viruses' on its own as a method of identifying malware.

Example answers and how they were marked

Full marks6/6

A virus could spread through the files the volunteers download and delete the charity's donation records, and spyware could record staff keystrokes and send passwords to a hacker. The anti-malware software would scan each laptop, including downloaded files and email attachments, and compare their code with a database of known malware patterns. If a match is found, the file is quarantined so that it cannot run, and it can then be deleted, so one infected laptop is less likely to pass malware to the other 14. The database of definitions must be kept up to date, because new malware will not be recognised by an old database. The manager should also train staff not to open unexpected attachments, and keep backups, because anti-malware cannot repair files that have already been damaged.

Why: Level 3: the effects of a virus and spyware are applied to the charity's laptops and records, and signature comparison, quarantine and deletion are explained and linked to stopping the spread (AO1/AO2), with accurate limits on what the software can do.

Some marks2/6

The anti-malware software scans the laptops and finds viruses. When it finds one it deletes the file so the laptop is safe. The charity should keep the software updated.

Why: Level 1 (2 marks): basic, independent points are made — deleting the infected file and keeping the software updated — but there is no identification method (signatures, heuristics or a sandbox), no explanation of how malware could affect the charity, and little linkage or application.

No marks0/6

The anti-malware software is a firewall that stops hackers getting into the laptops from the internet, and it scans the files for viruses.

Why: Level 0: describing anti-malware as a firewall is a misconception and is not credited, and bare 'scans the files for viruses' is not accepted on its own as a method of identifying malware, so there is no rewardable content.

5Discuss6 marksTranslators Swap Remove

A student is writing a program in a high-level language. The student runs the program after every small change to check that it works.

Discuss whether the student should use an interpreter or a compiler while writing and testing the program.

Your answer should include:

how each translator deals with a syntax error
how much of the program is translated at a time
how this affects the student's testing.

[6 marks]

Mark scheme

Indicative content

How each translator deals with a syntax error

An interpreter stops as soon as it finds a syntax error and displays an error message.
With an interpreter, the lines before the error have already been executed, so the student can see how far the program got before it stopped.
A compiler reports errors at the end of translation, so the student gets a list of all the syntax errors in the program in one go.

How much of the program is translated at a time

An interpreter translates one line at a time and executes each line immediately.
A compiler translates the whole program in one go before any of it is run.
A compiler produces object code, so after every change the whole program must be compiled again before the student can run it.
An interpreter produces no object code, so the student does not have to wait for the whole program to be translated before it runs.

How this affects the student's testing

An interpreter suits this student because the program can be run straight away after each small change.
The interpreter stops at the first error found, so the student fixes that error and runs the program again, but may only find the next error on the next run.
Reporting every error at the end of compilation means the student can fix several errors at once, but cannot run the program until the whole program compiles.
The student should use an interpreter while testing, and compile the finished program once it works.

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)

Level 3 responses must relate the way each translator works to the student's testing, not just describe the two translators.

Do not accept answers about run-time or logic errors where no comparison of the translators is made.

Example answers and how they were marked

Full marks6/6

The student should use an interpreter while testing. An interpreter translates one line at a time and executes each line straight away, so as soon as the student has made a small change the program can be run without waiting for the whole program to be translated. If there is a syntax error, the interpreter stops at that line and displays an error message, and the lines before it have already been executed, so the student knows exactly where the problem is. A compiler translates the whole program in one go and only reports the errors at the end, so the student would get a list of all the syntax errors, but could not run any of the program until the whole program compiled successfully.

Why: Explains how each translator deals with a syntax error, how much is translated at a time (one line executed immediately against the whole program at once) and links both to the student's testing, with a conclusion. Level 3.

Some marks4/6

An interpreter translates one line at a time and stops when it finds an error, so the student can see where the error is. A compiler translates the whole program and reports all the errors at the end. The interpreter is better for testing because the student can run the program straight away after a change.

Why: Adequate: correct points about error reporting and one line at a time, with a recommendation, but the effect on testing is only asserted rather than reasoned through, so the linkage is not sustained. Level 2.

Some marks1/6

The student should use a compiler because it translates the program one line at a time and stops at the first error, which makes testing quicker.

Why: The roles of the two translators are reversed, so the answer only makes a basic point about testing more quickly. Level 1.

Edexcel GCSE Computer Science (1CP2) Exam Questions

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Questions by topic

2.1 Binary

2.2 Data representation

2.3 Data storage and compression

3.1 Hardware

3.2 Software

3.3 Programming languages

4.1 Networks

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