Data representation

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Sample objectives

What this unit covers

• Number systems: Comprehend the reasons and methods by which computers utilize binary to represent various types of data. Note: All data must be converted to binary for computer processing, which involves logic gates and storage in registers.
• Number systems: (a) Grasp the concepts of denary, binary, and hexadecimal number systems. (b) Be able to convert between (i) positive denary and positive binary, (ii) positive denary and positive hexadecimal, (iii) positive hexadecimal and positive binary. Note: Denary is base 10, binary is base 2, and hexadecimal is base 16. Only integer values will be used, and conversions must be performed in both directions, with a maximum binary number length of 16 bits.
• Text, sound and images: Comprehend the methods and reasons behind how computers represent text, including the use of character sets like ASCII and Unicode. Notes: • Text is transformed into binary for computer processing. • Unicode supports a wider variety of characters and symbols compared to ASCII, accommodating multiple languages and emojis. • Unicode requires more bits per character than ASCII.
• Text, sound and images: Grasp how and why computers represent sound, focusing on the impact of sample rate and sample resolution. Notes: • Sound waves are sampled to convert sound into binary for computer processing. • Sample rate refers to the number of samples taken per second. • Sample resolution indicates the number of bits per sample. • Higher sample rates and resolutions lead to better recording accuracy and larger file sizes.
• Data storage and compression: Recognize the units used to measure data storage, including bit, nibble, byte, kibibyte (KiB), mebibyte (MiB), gibibyte (GiB), tebibyte (TiB), pebibyte (PiB), and exbibyte (EiB), along with the number of smaller units contained in each, such as 8 bits in a byte and 1024 mebibytes in a gibibyte.
• Data storage and compression: Determine the file size of an image and a sound file based on provided information, ensuring calculations are done using 1024 as the base unit rather than 1000, and include factors like image resolution, color depth, sound sample rate, and track length. Recognize that compression is used to decrease file size.