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

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:

• Statements are written using words/phrases that look like English or maths (1) so the code is easier to read/understand/write (1)
• One statement is translated into several machine code instructions (1) so programs are shorter to write than in a low-level language (1)
• High-level languages provide built-in data structures such as arrays/lists/records (1) so a collection of data items can be stored and accessed under one name (1)

Do not accept responses that only give a benefit or drawback, such as 'it is easier to learn', with no characteristic.

Do not accept 'it is easier than a low-level language' without saying what the characteristic is.

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.