Ch 7 · Representing Text · Theory

Topic 7 of 14 in Data Representation — How Computers Store Everything as Numbers — 2 lessons.

Character Sets: ASCII

Text is stored by agreeing a code number for every character — a character set. The classic one is ASCII, which uses 7 bits (0–127) to cover English letters, digits, punctuation and control codes.

Unicode: Beyond English

ASCII only has 128 codes — no room for Arabic, Chinese, emoji, or accented letters. Unicode extends the idea to over a million code points, covering essentially every writing system (and 😀). ASCII is deliberately the first 128 codes of Unicode, so old text still works.

All topics in Theory Data-representation

  1. Why Computers Use Binary
  2. Counting in Binary
  3. Hexadecimal — Shorthand for Binary
  4. Binary Addition & Overflow
  5. Negative Numbers — Two's Complement
  6. Logical Binary Shifts
  7. Representing Text
  8. Representing Images
  9. Representing Sound
  10. Storage Units & Compression
  11. Floating-Point Numbers (A Level)
  12. More Number Representations
  13. File Organisation & Access (A Level)
  14. Check Your Understanding