Edexcel GCSE Computer Science (1CP2) Exam Questions

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

• Reduces/makes the size of a file smaller (1)
• No data is lost/removed (during compression) (1)
• The original file/data can be recreated/restored exactly (1)

Allow 'the compressed file takes up less storage space' for the first mark.

The second and third bullets are two ways of making the same point: award a maximum of one mark for them, so a response that says no data is lost and that the original file can be restored, but does not say the file is smaller, scores one mark.

Do not accept descriptions of lossy compression, e.g. 'it removes data that is not needed to make the file smaller'.

Ignore reference to download/transmission times, bandwidth and streaming, as these are benefits of compression and not part of the definition.

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

• Makes a file/files smaller (1) so less storage space is needed on the disk (1)
• Reduces the size of the data (1) so it takes less time to upload/download/transfer the file (1)
• Compresses files/folders into a single file (1) so an attachment is under the size limit for email (1)
• Reduces the size of the files (1) so more of them fit onto a storage device/backup media (1)

Do not accept 'it compresses the files' on its own, as this repeats the question.

Do not accept responses about protecting files from malware/viruses or about deleting files.

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

• Instructions can manipulate/control the hardware/memory/registers directly (1) so the driver can control the specific device it is written for (1)
• The code is written for one specific processor/architecture (1) so it works with the exact hardware it will control (1)
• The programmer controls exactly how memory/registers are used (1) so the code is efficient and needs little memory, which suits a device that has limited memory (1)
• Each instruction maps to one machine code instruction (1) so the driver code is small enough to fit in the memory of the device (1)

Extra detail, such as naming the device the driver controls, is not needed to earn the marks.

Do not accept 'it is closer to machine code' on its own: it must be developed to show how this helps the driver, e.g. it can control the hardware directly.

Do not accept 'it is faster/quicker' with no link to the hardware/device, e.g. the device responds quickly.

Do not accept 'it is easier to learn', 'it is easier to debug' or 'it takes less time to write'.

Indicative content

What a device driver is and how the operating system uses it

• A device driver is a program that controls a peripheral device such as a graphics tablet by communicating with the operating system.
• The driver translates instructions from the operating system into signals that the graphics tablet understands, and passes the artist's pen movements back to the operating system.
• The operating system loads the driver into memory when the tablet is connected, so that it can then send data to the tablet and receive input from it.
• Without a driver the operating system cannot control the tablet, so the tablet does not work.

Why each peripheral needs its own driver

• Every make and model of peripheral uses its own set of commands, so a driver is written for that particular device.
• The drivers already installed for the studio's older tablets do not work with the new model, even though both are graphics tablets.
• An operating system includes drivers for many common devices, but it does not have one for a brand new model.
• The correct driver means the pen movements are received by the computer in the form the drawing program expects.

What must be done before an artist can use a new tablet

• The new tablet is supplied with its driver on a disc or as a download, and it must be installed on each computer.
• The operating system may need to be updated so that it recognises the new model.
• The driver must be enabled or selected for the tablet once it is installed.
• Drivers are updated later to fix faults or to improve performance.
• If the correct driver is not installed, the tablet does not work or some of its features are not available.

Additional guidance

• Level 3 responses must explain why a driver is specific to a device and what must be done before an artist can use a new tablet, as well as describing what a driver is, all applied to the studio.
• Responses that only state what a driver is, or that state a driver must be installed without explaining why the tablet needs its own driver, are limited to Level 1.
• Accept 'software', 'program' or 'set of instructions' for a driver.
• Do not accept a device driver described only as a cable or a physical connection.
• Do not accept the claim that all drivers are already built into the operating system, or that one driver works for every graphics tablet.

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)