Edexcel GCSE Computer Science (1CP2) Exam Questions

• B 4 (1)
• The only correct answer is B. The correct answer is 4 (2 bits give 2^2 = 4 values).
• A is not correct because 2 is the number of bits used to store each sample
• C is not correct because 8 different amplitude values would need 3 bits
• D is not correct because 16 different amplitude values would need 4 bits

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

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.

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.

Indicative content

Administrator accounts

• An administrator account can create new user accounts for new employees and delete accounts when employees leave.
• The administrator can reset a forgotten password, so an employee can get back to work without sharing another person's account.
• The administrator can set the access rights for each user or group, so designers get access to project folders and only directors can open salary files.
• Administrator privileges should be given to only a few trusted employees, as administrators can change any settings on the system.

Standard user accounts

• Designers should use standard user accounts, so they cannot install unauthorised software or change system settings.
• A standard user can be given permission to read and write files in the project folder that their team uses.
• Standard users should not be able to change other users' permissions, so the access rules cannot be removed by accident.
• If a standard user tries to open a file without permission, the operating system denies access.

File permissions

• Each file or folder can have permissions that allow a user to read, write or delete it.
• Project folders can be set so all designers can read and write the files inside them.
• Salary files can be set so only directors can read them, and other users are denied access.
• Permissions can be set for a group of users, such as all designers, which is quicker than setting them for each person.
• A file can be made read-only for standard users, so they can view it but cannot change it.

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 administrator accounts, standard user accounts and file permissions, and apply them to the design company.

Do not accept general operating system functions such as managing the processor or memory unless they are explicitly linked to controlling what a user can access.

Indicative content

Ease of learning, use and debug

• High-level language statements are written in English-like words and mathematical symbols, so the students can read the quiz game code and understand what each line does.
• The language is easier to learn than a low-level language, so students who are new to programming can start writing the quiz game quickly.
• Errors are easier to find and fix because the code is readable; for example, the students can check a line that updates a score against the rule they intended.
• The students do not need to know how the processor carries out each statement, so they can concentrate on the quiz questions and rules.

Data structures

• High-level languages provide lists or arrays, so the names and scores of all the players can be stored under one name and processed with a loop.
• A record can store a player's name and score as one item; in some languages a dictionary or class can be used instead, which keeps related data together.
• Using a data structure makes the code shorter and easier to understand than separate variables for every player's name and score.

Built-in functions and library routines

• High-level languages provide built-in functions such as print and input, so the students can display a question and read a player's answer without writing the underlying code.
• Library routines such as a random number generator can be used to choose quiz questions, saving the students time.
• String-handling routines can check or compare a player's answer, so the students do not have to write these routines themselves.
• Reusing tested routines reduces the amount of code the students write and can reduce errors in the quiz game.

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)

Additional guidance: Credit only points applied to the quiz game and the students; comparison with low-level languages is not required, but a correct contrast may support a point if it is applied. Do not award generic claims such as 'high-level programs run faster', 'work on any computer' or 'students do not need to learn syntax' unless they are justified for the quiz game.

Level 3 responses must cover all three bullet areas with linked reasoning that explains why the characteristic helps the students finish the game quickly with few errors; an answer covering only two bullet areas is limited to Level 2. Do not award the idea that high-level code is already machine code or is understood directly by the processor. Accept dictionaries or classes as equivalents of records.