Computer Hardware Components Overview

Study Notes

The system unit, or chassis, contains and protects the motherboard, hard drive, memory, and other hardware components.

The motherboard, also known as the system board, is the main circuit board.
Many electronic components, including the processor and memory, are attached to the motherboard or built in.
The central processing unit (CPU), often called the processor or the brain, is a silicon chip located in the CPU socket on the motherboard.
The heatsink and fan dissipate heat from the CPU.
The chipset controls communication between the CPU, memory, storage, and peripherals.

Random access memory (RAM) is the main temporary storage for data during computer operations, and data is lost when turned off.
The hard disk drive (HDD) is long-term storage which holds data even when the computer is off. Solid-state drives (SSDs) are alternatives in some systems.
The power supply unit (PSU) transforms AC electricity from the outlet (e.g., 120V or 220V AC) to DC electricity (e.g., 5V to 15V DC) used by computer components. A PSU usually has cooling fans.

Most motherboards have built-in video, sound, and network capabilities, but expansion slots are sometimes used to upgrade the computer's functionality.
Expansion cards (or adapter cards) add or improve certain functions.
Examples of expansion cards include Bluetooth adapters, MIDI interfaces, modems, network cards, sound cards, USB ports, video cards for enhanced graphics, and connections to additional monitors.

The Peripheral Component Interconnect (PCI) is an input/output pathway that connects the CPU to peripheral devices via expansion slots.
Serial Advanced Technology Attachment (SATA) is a computer bus interface that connects drive controllers and host bus adapters to mass storage devices like optical and hard disk drives.
The Complementary Metal Oxide Semiconductor (CMOS) battery stores essential settings when the computer is off, preventing reconfiguration after power loss.

The processor interprets and executes instructions to operate a computer.
In large computer systems (e.g., mainframes, supercomputers), processing may be distributed across multiple chips and circuit boards.
On personal computers, all processor functions are typically on a single chip called a microprocessor.

The Arithmetic Logic Unit (ALU) performs arithmetic and logic operations.
Arithmetic operations include addition, subtraction, multiplication, and division.
Logic operations include comparisons (greater than, less than, equal to).

The processor repeats four basic operations to execute instructions: Fetch, Decode, Execute, and Store.

A step-by-step explanation of the machine cycle using a calculator application as an example.

Registers are small, high-speed storage units in the processor used to temporarily hold data and instructions during the machine cycle.
Different types of registers exist in processors. For example, registers store instructions, data calculated by the ALU, location instructions were fetched from, and the calculated results.

The system clock, on a small quartz crystal circuit, controls the timing of all computer operations.
The system clock sends regular electronic pulses or ticks.
Each tick is a clock cycle; faster clock cycles allow for more operations per second.
Modern processors are superscalar which means they can execute multiple instructions per clock cycle.

Clock speed measures the pace of the system clock, defined as the number of ticks per second.
Modern processors usually operate in gigahertz (billions of cycles or ticks per second).
Faster clock speeds allow a processor to execute more instructions per second.