Computer Fundamentals (Bits, Bytes, Words)

Context: FIT1047_MOC · what every modern computer IS, and the units all data reduces to · feeds Number Systems (Binary and Hexadecimal) and Transistors and Logic Gates

Quick Revision

• 🎯 Objective: all modern computers = digital + electronic circuits + stored programs ➔ everything reduces to bits.
• ⚡ Key Constraint: bit → byte (8 bits, smallest addressable unit) → word (architecture-defined, 32/64-bit) — computers move/process/store whole words.

📝 Core

• Universal traits ➔ basically all modern computers are digital (0s/1s), use electronic circuits for computation, and are controlled by stored programs; most have CPU + RAM + I/O, many networked.
• Why 0/1 ➔ electronic circuits reliably distinguish two states (high/low) ➔ representation question (“how to encode data in bits?” → number systems, encodings) + computation question (“how to compute on bits?” → Boolean logic, circuits).
• Bit ➔ one binary digit ($0$ or $1$) — the smallest unit of data.
• Byte ➔ convention: $8$ bits; for many machines the smallest individually addressable memory unit.
• Word ➔ a block of bits of architecture-specific size; modern CPUs use $32$ or $64$ bits — the natural unit the CPU moves, processes and stores.
• Generations (context only, not assessed) ➔ vacuum tubes (1945–53) → transistors (1954–65) → integrated circuits (1965–80) → VLSI (1980–now) → 5th gen (quantum?).

⚠️ Common Mistakes

• 💡 Byte ≠ word ➔ byte is fixed at $8$ bits by convention; word size varies by architecture — quoting “a word is 8 bits” loses marks.

🧠 Active Recall

What three properties do essentially all modern computers share, and why do they use 0s and 1s?

Answer

• Short answer: digital, electronic-circuit-based computation, stored-program control; two states because circuits distinguish high/low reliably.
• Why: Two sub-problems follow ➔ representing information in bits (encodings) and computing with bits (Boolean circuits) — the unit’s Week 1–2 arc.

Define bit, byte and word, and state which one is architecture-dependent.

Answer

• Short answer: bit = one binary digit; byte = $8$ bits (smallest memory unit); word = architecture-defined block ($32$/$64$ bits on modern CPUs).
• Why: Word is the CPU’s native unit ➔ moves/processes/stores complete words, which is why word size defines an architecture.