Computer Hardware & Data Representation

Components in System Case

  • Case shields electronics; forms vary: desktop tower, all-in-one, laptop, tablet, smartphone, wearable, etc.
  • Internal core parts: processor (CPU), memory modules, motherboard, power supply/fan or battery, optional video & sound cards, ports.

Motherboard & Adapter Cards

  • Motherboard = main circuit board; hosts CPU, memory slots, chipset, buses, ports.
  • Adapter (expansion) cards add/boost features (e.g., video, sound); inserted into expansion slots.
  • Plug-and-Play auto-detects newly installed adapters.
  • USB adapters offer extra ports/functions for mobile devices.

Processor (CPU)

  • CPU interprets & executes instructions; key makers: Intel, AMD.
  • Multi-core = single chip containing \ge 2 separate cores.
  • Two main units:
    • Control Unit – directs operations.
    • Arithmetic Logic Unit (ALU) – performs arithmetic/comparison operations.
  • Registers: high-speed storage inside CPU.
  • System clock drives operations; speed ≈ \text{GHz}.
  • Heat management: heat sink, liquid cooling, cooling pads.

Machine Cycle (per instruction)

  1. Fetch – obtain instruction/data from memory.
  2. Decode – translate to executor signals.
  3. Execute – carry out command.
  4. Store – write result back to memory.

Memory

  • Stores OS, applications, and active data.
  • Addressable locations; size in \text{GB}/\text{TB}.

Volatile vs Non-volatile

  • Volatile: RAM (loses data when power off).
  • Non-volatile: ROM (firmware), flash memory, CMOS.

RAM

  • Two main categories: DRAM & SRAM.
  • DRAM variants: SDRAM, DDR, DDR2, DDR3, DDR4, RDRAM — each faster than prior.
  • Packaged on SIMM/DIMM modules; inserted into memory slots.

Cache Hierarchy

  • L1 (inside CPU, fastest), L2 (inside CPU, larger), L3 (separate, between CPU & RAM) – store frequently used data to speed processing.

Other Terms

  • Flash memory: electrically erasable/re-writeable.
  • CMOS: battery-powered storage for setup data.
  • Access time: nanoseconds (ns) needed to read memory.

Buses

  • Pathways for data/address/control signals.
  • Types: system bus, backside bus, expansion bus.
  • Word size = bits CPU processes at once.

Power Supply & Batteries

  • Desktop: PSU converts AC → DC.
  • Mobile: run on AC adapter or rechargeable lithium-ion batteries.

Data Representation

  • Analog: continuous; digital: two states (on/off).
  • Binary system digits (0,1); 8 bits = 1 byte (represents a character).
  • Character conversion: keyboard scan code → ASCII binary (e.g., 01010100 for ‘T’) → processed → output image.

Cloud Computing (Context)

  • Users adopt cloud for accessibility, cost, space, and scalability benefits.