Edexcel GCSE Computer Science (1CP2) Exam Questions

• A Address bus (1)
• The only correct answer is A. The correct answer is address bus. Do not accept 'address' on its own.
• B is not correct because the control bus carries control signals in both directions between the CPU and other components
• C is not correct because the data bus carries data in both directions between the CPU and main memory
• D is not correct because the system bus is the collection of all three buses

• C 128 (1)
• The only correct answer is C. The correct answer is 128.
• A is not correct because 6 bits give only 64 different combinations
• B is not correct because 127 is the largest 7-bit value, not the number of characters that 7 bits can represent
• D is not correct because 256 characters need 8 bits, as used by 8-bit extended ASCII

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

• Program instructions are stored in main memory/RAM (1)
• The data used by the program is stored in main memory/RAM (1)
• The CPU fetches/reads instructions from main memory to execute them (1)
• The program can be run without the instructions being input again (1)

Allow 'the program is stored in memory' for one mark.

Do not accept answers about programs being stored on secondary storage, such as a hard disk or USB memory stick.

Do not accept answers that only describe the von Neumann architecture (e.g. having a CPU and memory) without stating that instructions are stored in main memory.

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

• Sends outgoing email from the client to the mail server (1) so it can be forwarded/relayed to the recipient's mail server (1)
• Transfers email between mail servers (1) so it reaches the destination server (1)
• Pushes/sends the email message (1) because it handles outgoing mail while POP3/IMAP handle incoming mail (1)

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

Do not accept receiving/downloading email or storing email on the server, which is POP3/IMAP.

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.