Base CS from zero
What a computer is: free-recall review
Recall beats re-reading. For each prompt, say or write a full answer from memory before you open the model answer. The effort of reconstructing the idea — not recognising it — is what locks it in.
Reconstruct the unit’s spine without looking back: why two states, how place value turns bits into numbers, why bits need an encoding, why three boolean operations suffice, and how gates climb from logic to arithmetic.
- 01Why does hardware use exactly two states instead of ten, and what is a bit?
- 02Explain place value in binary and why each added bit doubles the representable range.
- 03What is an encoding, and why must it be agreed in advance? Give the byte 01000001 as an example.
- 04What is a truth table, and why is it the definition of a boolean operation rather than just a summary?
- 05State what 'functionally complete' means for AND, OR, NOT, and sketch why it holds.
- 06How does a half-adder turn gates into arithmetic, and which gate produces sum versus carry?
If you reconstructed each answer from memory, you hold the unit’s spine: two states win on noise margin; place value turns bits into numbers and each bit doubles the range; an agreed encoding is what gives bits meaning; a truth table fully defines a boolean operation; AND, OR, NOT (or NAND alone) are functionally complete; and gates wired into a half-adder reproduce addition — the first rung from logic up to a working CPU.