Cambridge O Level Computer Science · Syllabus 2210 · Data Representation
Unicode
What is Unicode?
Unicode is a character set that allows for a greater range of characters and symbols than ASCII, including different languages and emojis, and requires more bits per character than ASCII.
This definition is part of the Data Representation chapter in Cambridge O Level Computer Science.
Unicode in context
Text has to be converted to binary before a computer can process it. That conversion is done using a character set: an agreed table that gives every character a unique character code, which is then stored as a binary number. ASCII is one such character set. Unicode is another, and it allows for a far greater range of characters and symbols than ASCII, including different languages and emojis — but it requires more bits per character than ASCII.
Common mistakes with Unicode
- M11. "Unicode is a font." Why it fails A font is a set of shapes for drawing characters. Unicode is a character set: it assigns code numbers. Correct model Unicode allows for a greater range of characters and symbols than ASCII, including different languages and emojis, and requires more bits per character. Exam-safe "Unicode is a character set, not a font; it assigns a code to a far greater range of characters than ASCII." Test yourselfHideQ. Give one advantage and one disadvantage of Unicode over ASCII.A. Advantage: a greater range of characters and symbols, including different languages and emojis. Disadvantage: it requires more bits per character, so files are larger.