Edexcel GCSE Computer Science (1CP2) Exam Questions

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

• The compiler translates the whole program/complete source code in one go (1) whereas the interpreter translates one line/statement at a time (1)
• The compiler translates all of the source code before any of it is run/executed (1) but the interpreter translates each line/statement as it reads it (1)
• The interpreter translates one line/statement at a time (1) and the compiler translates the whole program/source code together (1)

Accept the compiler point and the interpreter point in either order.

Do not accept responses about object code/executable files, when the translated code is executed, how errors are reported, or speed/memory use.

Do not accept 'the interpreter executes/runs each line' on its own, without saying that it translates one line/statement at a time.

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

• Data is encrypted/scrambled (1) so it cannot be read/understood if it is intercepted (1)
• The customer's bank/personal details are kept secure/private (1) because the data is encrypted/scrambled during transmission (1)
• The customer's login details/password cannot be read by an eavesdropper (1) because HTTPS encrypts/scrambles the data sent to and from the web server (1)

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

Allow 'scrambled' as an alternative to 'encrypted'.

Do not accept 'it is more secure/safe' or 'the data is secure' on its own, without saying how it is made secure (e.g. encryption/scrambling).

Do not accept faster loading/speed, or claims that HTTPS stops viruses or always proves the website is genuine.

Indicative content

Allocating space

• The operating system checks that there is enough free space before a file is saved, so a large photograph does not make the save fail.
• The operating system finds free space on the disk and allocates it to the new file, so the file's data has somewhere to be written.
• Disk space is allocated so that a file is not written on top of data that already belongs to another file.
• When a file is deleted, the operating system marks its space as free so it can be used again by the next document that is saved.

Keeping track

• The operating system keeps a record of the name, size and location of every file, so it knows where each file is stored.
• The record is updated whenever a file is saved, renamed or deleted, so it still matches what is on the disk.
• The operating system uses this record to find a file again, so an employee can open a document or photograph that was saved earlier.
• The record lets the operating system tell the two employees' documents and photographs apart, even though they are all on the same disk.

Without this management

• Two files could be given the same space, so one document would overwrite another and the work would be lost.
• The operating system would not know where a file is stored, so a saved document could not be found and opened again.
• Space used by deleted files might never be freed, so the disk would fill up and new files could not be saved.

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 the allocation of space and the tracking of files, with at least one consequence of no management linked to its cause. Reference to a file being split across blocks that are not next to each other, or to the record holding the location of each block, is Level 3 detail and is not required.

Basic, unlinked points with no application to the business's documents or photographs, and a consequence such as 'files would be lost' with no cause given, are limited to Level 1; to reach Level 2 a point must be linked to a reason (for example, the record is kept so a document can be found again) and be applied to the context. Do not accept defragmentation, process scheduling, user management, peripheral management, or backup and antivirus scanning, as file management.