Computer Science (0984) 2023 - 1 Data Representation (1-3)

1-3 Data Storage and Compression

1-3-1 Understand how data storage is measured

• A binary digit is referred to as a bit, 8 bits is a byte.
• A byte is used tomeasure memory size.
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1-3-2-1 Calculate the file size of an image file using information given

• File sizes range from bits, bytes and kibibytes (the smallest sizes) to (and beyond) gibibytes, tebibytes, pebibytes and exbibytes (the bigger ones)
• File size factors:
  • The higher the number of pixals within an image the more space is needed to store it
    More pixals = greater image file size
  • Resolution
    • Number of pixals in an image is the resolution
    • Represented as width x height
  • Metadata
    
    • Metadata is the information about the data rather than the actual data.
    • It may include camera settings, date & time, location etc
  • Bit depth
    
    • This is the storage space each pixal needs to represent the range of different colours.
    • In a black and white image, there are two colours, black and white therefore one binary bit: 1 = white and 0 = black
    • Colour images need…