Edexcel curriculum (2015)
AlgorithmsApplication sof'wrAsciiBinaryCacheClient-ServerCloudCompressionComputational thinkCPUCyber securityDatabaseFetch-d-e cycleEmbedded systemEncryptionEnvironmentEthicsFile sizeFlow chartHexadecimalHigh Level languageISP/InternetLaw & LegislationLogicMagnetic HDDNetworkingOpen sourceOperating systemOptical storagePeer to peerPictures (data rep)ProtocolsRun length encodingRAMROMSimulation softwareSolid state HDSoundStored programUtility Sof'wre |
Compression
Answer
Any one of: To reduce download time/increase transfer speed To reduce amount of storage space required Lossy compression
Answer
Any two of: Not all pixels are recorded Quality/detail reduced Only suitable when images have lots of the same pixels Cannot reproduce original using the lossy data Compression
Answer
Any two of the following: File sizes / download times will be reduced. (1) Some loss of image data / image quality will occur. (1) JPEGs allow image quality to be fine-tuned / the level of compression to be adjusted. (1) Compression - lossless
Answer
An explanation that makes reference to the following points: • lossless compression ensures that no data is lost (1) • so that the desktop published file can be restored so that it is exactly the same as the original (1) Compression - lossy
Answer
Any two from: • Data is removed during the compression process (1) • The removed data is not normally noticed by a human (sight, sound) (1) • The original contents of the file cannot be restored exactly (1) Compression - RLE
Answer
• Letters in correct order (1) • Correct number (1) Either: 3b 1r 4g 2r Or b3 r1 g4 r2 Run length encoding
Answer
Any one of: R4B2R1Y3 R4B2RY3 4R2BR3Y 4R2B1R3Y With one incorrect character or digit award a maximum of 1 mark. Run length encoding
Answer
This sequence has very few repeated patterns (1), therefore using a RLE will not lead to a significant reduction in the file size / not compress the image very much. (1) |