Edexcel GCSE Computer Science (1CP2) exam questions

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Practice paper

6 questions · 14 marks

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1Multiple choice1 markCharacter Sets Swap Remove

ASCII is a character set used for representing text.

Identify the number of bits used to encode each character in ASCII.

[1 mark]

Mark scheme

B 7 (1)
The only correct answer is B. The correct answer is 7 bits.
A is not correct because 6 bits give only 64 different characters
C is not correct because 8 bits are used by extended ASCII to give 256 characters
D is not correct because 16 bits give 65 536 different characters, which is far more than the 128 in ASCII

Example answers and how they were marked

Full marks1/1

B 7

Why: B is the only correct answer: each ASCII character is encoded using 7 bits (1).

No marks0/1

C 8

Why: Near miss scoring 0: 8 bits is extended ASCII, and the scheme's C line says extended ASCII, not ASCII, is not the answer.

No marks0/1

A 6

Why: Misconception scoring 0: 6 bits give only 64 different characters, so it cannot be ASCII.

2Short 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.

3Short recall2 marksUnits & Conversion Swap Remove

Data storage is measured in binary multiples.

Define the term bit.

[2 marks]

Mark scheme

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

A binary digit (1)
Has the value 0 or 1 (1)
The smallest unit of data storage (1)
A single 0 or 1 (1)

Allow binary digit/binary place value for binary digit

Allow a single binary digit for a single 0 or 1

Do not accept a group of 8 bits/half a nibble of 4 bits, which describe a byte or a nibble

Do not accept a binary number/binary on its own

Example answers and how they were marked

Full marks2/2

A binary digit that can have the value 0 or 1.

Why: A binary digit (1) and has the value 0 or 1 (1).

Some marks1/2

It is the smallest unit of data storage.

Why: Smallest unit of data storage (1), but does not state that it is a binary digit or that it has the value 0 or 1.

No marks0/2

A group of 8 bits.

Why: Describes a byte, not a bit; no creditworthy point and named in the Do not accept line.

4Describe2 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.

5Explain2 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.

6Discuss6 marksUser Management Swap Remove

A school library has 24 computers that are shared by students and teachers throughout the day. Each computer runs an operating system. The school wants users' work to be kept private and the computers to be used only by authorised people.

Discuss how the operating system's user management features can be used to share the computers securely.

Your answer should include:

user accounts
authentication
the benefits for the school.

[6 marks]

Mark scheme

Indicative content

User accounts

Each student and teacher should have their own user account, so the operating system can identify the person who is logged on.
The operating system keeps a record of all valid users on the computer, so unknown users are not allowed to log in.
A separate home area or folder can be created for each account, so a student's saved work is kept apart from other users' work.
An account can be disabled when a student leaves the school, so they can no longer access the computers.

Authentication

A username and password can be required at login, so only users with the correct details can use the computer.
The operating system checks the entered password against the stored password for that account before allowing access.
Users should be encouraged to choose a strong password, which makes it harder for someone else to guess and log in.
The operating system can lock an account after several failed login attempts, which reduces the chance of someone trying passwords repeatedly.

Benefits for the school

Many students can share the same computers because each person's files are kept separate.
Work is less likely to be deleted or changed by another student, because users only see their own files.
The school can see which account was used on a computer, so misuse can be traced to a user.
Teachers can be confident that only authorised people can use the library computers.
The school does not need a separate computer for every student, so it saves money.

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 user accounts and authentication, and apply them to the school library.

Do not accept general operating system functions such as file management or process management unless they are explicitly linked to managing users.

Example answers and how they were marked

Full marks6/6

Each student and teacher should have their own user account with a username and password. When someone logs in, the operating system checks the password against the one stored for that account, so only authorised people can use the computer. Each account can have its own home folder, so a student's work is kept private and another student cannot open or delete it. If a student leaves the school, their account can be disabled so they cannot log in again. This lets the school share a smaller number of computers safely, as each user's work stays separate and any misuse can be traced to the logged-in account.

Why: Level 3. It explains user accounts, authentication and benefits, with sustained links to sharing computers in the school library.

Some marks4/6

Every user should have a username and password. The operating system checks the password so that people who are not allowed cannot log in. Each user should also have their own area to save files so they do not delete other people's work.

Why: Level 2. Basic accounts and authentication points are made and linked, but the benefits to the school are only briefly applied and not developed.

No marks0/6

The operating system manages the users by looking after the files in folders and by making sure the printer works for everyone. It also keeps the computer running quickly when lots of students use it.

Why: Level 0. These are general operating system functions such as file management and peripheral management, not user management, so no creditworthy point is made.

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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