An Agreed Code: How the Same Bits Mean Letters or Colours
A pattern of bits means nothing on its own. It becomes a letter, a colour or a note only because a code says so, and both ends have to be using the same code.
What a learner can do afterwards
- Invent a code for a small set of symbols and use it to send a short message to someone holding the same code
- Show what comes out when the two ends use different codes for the same bits
- Give two things the same bit pattern could stand for in two different files
1 · Read
A pattern of bits means nothing on its own. It becomes a letter, a colour, or a note only because a code says so. Both ends must use the same code, or the message scrambles.
One computer sends the bits 01001000 01101001, and a friend reading them with the letter code sees Hi. Another computer reads the same bits with a number code and gets 18537. Same bits, two meanings, because the codes differ.
You and a friend can invent a code for a few symbols and swap messages with it. If you shift every letter one step forward, Hi becomes Ij. Your friend decodes it only because she holds the same rule.
When a message looks like nonsense, suspect a code mismatch before you blame the sender. Ask which code each end used. The same eight bits can be a letter in one file and a shade of grey in another.
Bits borrow meaning from a shared code, so matching codes at both ends keeps messages clear.
2 · Watch
Take it off screen
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.