Edexcel GCSE Computer Science (1CP2) Exam Questions

• A They are lost (1)
• The only correct answer is A. The correct answer is They are lost
• B is not correct because RAM is volatile and its contents are lost when the power is switched off, so they are not stored permanently
• C is not correct because RAM is volatile and its contents are lost when the power is switched off, so they are not saved to secondary storage
• D is not correct because ROM is read-only memory that holds the start-up instructions, so the contents of RAM are not written to it

• A Blu-ray Disc (1)
• The only correct answer is A. The correct answer is Blu-ray Disc.
• B is not correct because a CD stores less data than a Blu-ray Disc, up to about 700 MB
• C is not correct because a DVD stores less data than a Blu-ray Disc, up to about 4.7 GB (single-layer) or 8.4 GB (dual-layer)
• D is not correct because magnetic tape is not an optical storage medium

Award one mark for:

• Volatile (1)

Allow volatile memory / it is volatile.

Do not accept non-volatile, ROM, RAM or temporary/short term memory on their own, as these are not the term asked for.

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

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

• Stores programs (including the operating system) and data that are not currently in use (1) so that they can be loaded into RAM/main memory when needed (1)
• Keeps files/programs/data when the power is turned off (1) which happens because it is non-volatile (1)
• Stores files/data for backup or archiving (1) so that they can be recovered if the originals are lost/corrupted (1)

A correct role on its own earns one mark; the second mark requires a linked development.

Accept either order if both the role and the link are given.

Do not accept 'it is non-volatile' on its own, unless it is linked to keeping data when the power is turned off.

Do not accept answers that only name a storage type (magnetic, optical, solid state) without describing a role.

Do not accept responses that describe primary storage/RAM, e.g. storing the data/instructions the CPU is currently working on, or that secondary storage makes the computer run faster.

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

• A read/write head moves over the surface of the disk (1) to read/write data by detecting or changing the magnetic alignment of areas of the surface (1)
• The head magnetises areas of the disk surface in different directions (1) so each area represents a binary 1 or 0 (1)
• Data is stored on concentric circles called tracks (1) which are divided into sectors (1)

Allow one mark for tracks/concentric circles on their own.

For the second mark in the first two bullets, the response must refer to the magnetic alignment/charge being detected or changed, not just that the head reads/writes data.

Do not award a mark for 'it is magnetic' or 'it stores data in binary' with no description of how the data is stored.

Do not accept descriptions of optical storage (e.g. a laser, pits and lands) or solid state storage (e.g. electric charges in chips).

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

• A temperature sensor measures/reads the temperature in the greenhouse (1) which the processor compares with the value stored in the system (1)
• The heater is switched on (1) when the temperature reading goes below the value stored in the system (1)
• A fan/vent/window is opened/a cooler is switched on (1) when the temperature reading goes above the value stored in the system (1)
• The temperature is checked/measured continuously (1) so the heater/fan is switched on or off as soon as the temperature changes (1)

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

Allow one mark for a correct point on its own without a linked reason, e.g. 'a temperature sensor measures the temperature'.

Do not award 'the embedded system controls/keeps the temperature correct' as this repeats the question.

Do not accept naming a device without saying what it does, e.g. 'the greenhouse has a thermostat'.

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

• The instructions/program instructions and data are stored together in main memory/RAM (1) so the CPU can fetch each instruction (from its address) and execute it (1)
• The instructions/program instructions are held in main memory/RAM (1) rather than being built into/part of the hardware, so the computer does not need to be rewired/rebuilt to run a different program (1)
• The next instruction to be executed/instruction is held in main memory/RAM (1) so the CPU can fetch it using its address before it is decoded and executed (1)

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

A point/statement on its own can only earn one mark.

Do not accept a response that only refers to data being stored in main memory/RAM without referring to the instructions/program instructions.

Do not accept instructions/programs being stored on the hard disk/backing store.

Do not accept 'the program is stored in memory' without saying that it is the instructions/program instructions that are stored there.

Indicative content

Stored program concept

• Instructions and data are stored together in the same main memory (RAM).
• Instructions are fetched one at a time from memory and executed in sequence.
• The program can be changed by loading different instructions into RAM.
• The CPU can only execute instructions that are in main memory.

Role of RAM

• RAM holds the program instructions and the data being used.
• The address of the next instruction is held in the program counter (PC).
• The instruction is fetched from RAM using the address bus.
• The data bus carries the instruction from RAM to the CPU.
• RAM is volatile, so programs are lost when power is off.
• RAM is directly accessible by the CPU, unlike secondary storage.

Benefits

• The same hardware can run many different programs.
• Programs can be loaded and changed quickly.
• No need to rewire the computer for a new task.
• Makes general-purpose computers possible.

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)