Edexcel GCSE Computer Science (1CP2) exam questions

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Practice paper

6 questions · 20 marks

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1Short 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.

2Describe2 marksUtility Software Swap Remove

A student has a large number of photographs stored on a computer.

Describe the purpose of data compression software.

[2 marks]

Mark scheme

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

Makes a file/files smaller (1) so less storage space is needed on the disk (1)
Reduces the size of the data (1) so it takes less time to upload/download/transfer the file (1)
Compresses files/folders into a single file (1) so an attachment is under the size limit for email (1)
Reduces the size of the files (1) so more of them fit onto a storage device/backup media (1)

Do not accept 'it compresses the files' on its own, as this repeats the question.

Do not accept responses about protecting files from malware/viruses or about deleting files.

Example answers and how they were marked

Full marks2/2

It makes the files smaller (1) so that they use less storage space on the computer and more of them fit on the disk (1).

Why: The point (1) and a linked development giving the benefit (1).

Some marks1/2

It makes files smaller.

Why: This is the point (1) but there is no development of what the smaller size leads to, so only one mark.

No marks0/2

It protects the files from viruses so that they cannot be damaged.

Why: This describes anti-malware software, which the mark scheme does not accept; no creditworthy point is made.

3Describe2 marksLow and High Level Languages Swap Remove

A programmer has written a program in assembly language.

Describe why it is necessary to translate the program into machine code before it can be run.

[2 marks]

Mark scheme

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

The processor/CPU can only execute machine code/binary instructions (1) so the assembly instructions must be converted into machine code before the program can run (1)
Each assembly instruction/mnemonic matches/corresponds to one machine code instruction (1) so each line must be replaced with the machine code the processor executes (1)
The program is written using mnemonics (1) that must be translated into machine code for the processor to carry out the instructions (1)
The hardware/processor does not understand assembly language directly (1) so it must be translated into machine code that the processor can execute (1)

Do not accept 'assembly language is a low-level language'.

Do not accept 'it is hard to understand' or 'it is not English'.

Do not accept benefits, such as 'machine code runs faster' or 'the program will run more quickly'.

Do not accept 'an assembler/a translator converts it' on its own, with no reference to the processor only being able to execute machine code/binary.

Do not accept responses about high-level languages or about compilers/interpreters.

Example answers and how they were marked

Full marks2/2

The processor can only execute machine code, so the assembly instructions must be converted into machine code before the program can run.

Why: States what the processor can execute (1) and links it to converting the program's instructions into machine code (1).

Some marks1/2

Each assembly instruction matches one machine code instruction.

Why: Correct point about the one-to-one match (1) but no development saying that this is because the processor only executes machine code.

No marks0/2

Because an assembler translates assembly language into machine code.

Why: Names the translator but gives no reason tied to the processor only being able to execute machine code, so no mark; this is in the 'Do not accept' guidance.

4Explain2 marksProtocols & Layers Swap Remove

Two computers exchange data over a network.

Explain why network protocols are needed for the two computers to communicate.

[2 marks]

Mark scheme

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

Devices (can) understand/interpret the data they receive (1) because they follow the same set of rules for communication (1)
Data is sent in an agreed format/structure (1) so the receiving device can interpret/understand it correctly (1)
Devices (can) connect/communicate successfully (1) because they agree how the data is transmitted, such as the type of signal used (1)
Errors (can) be detected/handled (1) because both devices follow the same rules for checking the data (1)

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

Do not accept 'so devices can talk/communicate with each other' or 'so they can understand each other' without saying they follow the same rules/agreed format.

Do not accept an answer that only states protocols are a set of rules, without saying what this allows (e.g. the data can be understood/interpreted).

Do not accept a faster connection/speed as a reason why protocols are needed.

Do not accept naming a protocol (e.g. TCP/IP, HTTP, Wi-Fi) without an explanation of why it is needed.

Do not accept a description of what a protocol does (e.g. 'TCP splits data into packets') without saying why this is needed.

Example answers and how they were marked

Full marks2/2

Devices can understand the data they receive (1) because they follow the same set of rules for communication (1).

Why: Linked point (1) and reason (1): following the same rules is what lets the devices understand the data.

Some marks1/2

Data is sent in an agreed format (1).

Why: Point (1) identified, but no linked reason saying what the agreed format achieves.

No marks0/2

Protocols are needed so the connection is faster (0) because more data can be sent at once.

Why: Speed is not a reason protocols are needed, so there is no creditworthy point or linked reason.

5Discuss6 marksSoftware Basics Swap Remove

A dental practice has a network of computers used by receptionists, dentists and managers. Patient records are stored in shared folders and staff have different levels of access.

Discuss how the operating system's file management and user management support the dental practice.

Your answer should consider:

file management
user management

[6 marks]

Mark scheme

Indicative content

File management

The operating system organises the practice's patient records into folders, so staff can find a patient's record quickly during an appointment.
It carries out file operations such as saving, moving, renaming and deleting, so a dentist can save updated notes to the correct record.
It sets permissions on shared folders and files, so that only authorised staff, such as dentists, can open a patient's clinical records; this reduces the risk of confidential records being seen by the wrong staff.
It can give read-only access to some files, so receptionists can view appointment details but cannot change clinical notes.
It shows the size of files and the free space on the practice's shared storage, so managers can see when more storage is needed for records.

User management

The operating system creates a user account for each member of staff, with a username and password, so that each person has their own access to the system.
It allocates access rights to each account, so receptionists, dentists and managers each see only the folders and files their role needs.
It allows accounts to be grouped by role, so a new dentist can be given the same permissions as the existing dentists quickly instead of setting each one by hand.
It can require strong passwords, which makes it harder for one member of staff to log on using another person's account and open patient records.
It can disable or delete an account when a member of staff leaves, so that they can no longer open patient records.

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 file management and user management and develop how each supports the practice, for example linking permissions to who can open patient records. Answers that only state basic, undeveloped points such as 'the operating system puts files in folders' or 'users have a username and password', with little reference to the practice, are limited to Level 1 (maximum 2 marks).

Do not accept backup, disk defragmentation or anti-malware software as operating system file management, or encryption, as these are outside the operating system's file management; they are utility software or security measures.

Example answers and how they were marked

Full marks6/6

The operating system's file management lets the practice keep each patient's records in folders, and it carries out the saving, moving and deleting of those files, so a dentist can add notes to the right record after an appointment. File management also sets permissions on the shared folders, so receptionists can be given read-only access to appointment details but cannot change clinical notes, while dentists have write access. This reduces the risk of confidential patient records being seen or changed by the wrong staff. User management supports this because the operating system gives every member of staff their own account with a username and password, so anything done to a record can be traced to the person who did it. Accounts can be grouped by role, so when the practice takes on a new dentist the account can be given the same rights as the other dentists quickly rather than setting each permission by hand. When a member of staff leaves, their account can be disabled so they can no longer open patient records. Together this means the practice can share records across reception, dentists and managers while each person only reaches what their role needs.

Why: Level 3: both file management (folders, saving, permissions, read-only access) and user management (accounts, grouping by role, disabling accounts) are covered and developed, with sustained reasoning linking them to the practice's shared records and staff access.

Some marks2/6

File management puts the patient records into folders so they can be found. User management gives each member of staff a username and password so they can log on to the computer.

Why: Level 1: two basic, independent points, one on each area, with little development and little application to how they support the practice, so it is capped by the Level 1 guidance at 2 marks.

Some marks1/6

File management is when the operating system backs up all the files every night. User management is when the computer has a username so it stops viruses.

Why: Level 1 (1 mark): backup is not accepted as operating system file management, but the basic point that a user account has a username is creditworthy; the claim that it stops viruses is not creditworthy.

6Discuss6 marksLow and High Level Languages Swap Remove

A company is developing the firmware for a robotic vacuum cleaner. The firmware must read the distance sensors and control the motors. The vacuum cleaner has a small amount of memory.

Discuss the characteristics of a low-level programming language that make it suitable for writing the firmware.

Your answer should include:

control of the hardware
the efficiency of the code
the link between the language and the processor.

[6 marks]

Mark scheme

Indicative content

Control of the hardware

Low-level languages can read and write the contents of registers and memory addresses directly, so the firmware can take the values from the distance sensors without calling a library routine.
Assembly language instructions can read from and write to specific input/output ports on the vacuum cleaner's processor, so the motors can be switched on and off directly.
The programmer decides exactly which processor operations are carried out and in which order, which matters when the vacuum must reverse away from a step or an obstacle.
A low-level language puts nothing between the program and the hardware, so the programmer can control the hardware of the vacuum cleaner precisely.

Efficiency of the code

Assembly language code can be hand-optimised instruction by instruction, so the code that checks a sensor is as short as possible.
The programmer can choose which registers hold values that are used again and again, which cuts down the number of memory accesses the firmware needs.
A hand-written low-level program can be made compact, so it is more likely to fit in the small amount of memory the vacuum cleaner has.
Because each instruction does one defined job, the time taken to react to a sensor reading is predictable, which suits firmware that must not overrun.

Link between the language and the processor

Low-level languages are processor-specific, so the instructions used are those of the exact processor in the vacuum cleaner rather than general statements that need translating.
Each assembly language instruction maps to one machine code instruction, so the programmer knows precisely which processor operation will be carried out by each line of code.
An assembler turns each mnemonic into its machine code equivalent, so the machine code running on the vacuum cleaner's processor is exactly what the programmer wrote.
Code written for a different processor would have to be rewritten, which is acceptable here because the vacuum cleaner always uses the same processor.

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)

Within Level 1, award 1 mark for a single basic point and 2 marks for two or more independent basic points; Level 2 requires the points to be linked to the vacuum cleaner; Level 3 requires both control of the hardware and efficiency of the code, and a few concise, linked sentences can reach Level 3, so extra length is not required.

Accept registers, memory addresses, input/output ports, machine code and mnemonics as ways of describing access to the hardware, and accept 'a low-level language is faster' as a basic point on its own. Do not award 'binary is a low-level language' (machine code is written in binary, but binary is not a language), or characteristics of high-level languages such as being easy to read or portable, as characteristics of a low-level language.

Example answers and how they were marked

Full marks6/6

A low-level language can read and write to registers and to input/output ports directly, so the firmware can take the distance sensor readings and switch the motors without needing library routines. It can be hand-optimised instruction by instruction, so the code that checks a sensor is short and the time it takes is predictable, and a compact program is more likely to fit in the vacuum cleaner's small memory. The language is processor-specific and each assembly instruction maps to one machine code instruction, so the programmer knows exactly which operation the vacuum's processor will carry out, and the assembled machine code is exactly what they wrote.

Why: Covers all three bullets: direct control of registers and ports applied to the sensors and motors, hand-optimised compact code with predictable timing applied to the small memory, and the one-to-one link to the processor's own instruction set. Linked and applied throughout, so Level 3.

Some marks2/6

A low-level language can control the hardware directly. It can read the sensors and control the motors. It is also faster than a high-level language, so the vacuum responds quickly. This is useful because it has little memory.

Why: Three basic, independent points: direct control of the hardware applied to the sensors and motors, faster execution, and suitability for limited memory. They are asserted without development (no registers, ports or predictable timing) and the link between the language and the processor is missing, so Level 1, two or more basic points (2).

Some marks1/6

A low-level language is written in binary, so the computer can understand it directly. It is faster than a high-level language.

Why: 'Faster than a high-level language' is a creditworthy basic point (1). 'Written in binary' is not awarded, as binary itself is not a language and the do-not-award rule applies. Only one undeveloped point with no application to the vacuum cleaner, so Level 1, single basic point (1).

Edexcel GCSE Computer Science (1CP2) Exam Questions

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Practice paper

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

4.2 Network security

5.1 Environmental

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