Computer Science 8: Chapter 4 - Hardware Overview

Hardware

Refers to the physical components of a computer

CPU (Central Processing Unit)

"Brain" of the computer that processes commands from software and controls functions performed by other components

Control Unit

Part of the CPU that executes instructions

Arithmetic Logic Unit (ALU)

Part of the CPU that performs calculations, including arithmetic calculations (addition, subtraction, etc.) and logical calculations (comparisons)

Instruction Cycle

Sequence a CPU (Control Unit) goes through to execute a command: Fetch - retrieves instruction from RAM/cache, Decode - determines what the instruction is, Execute - performs commands, Store - store any result to RAM

Fetch

Retrieves instruction from RAM/cache

Decode

Determines what the instruction is

Execute

Performs commands

Store

Stores any result to RAM

Clock Speed

The speed at which a processor executes the instruction cycle

Gigahertz (GHz)

1 billion cycles per second

Megahertz (MHz)

1 million cycles per second

Multi-Core Processors

Two or more processors integrated on a single chip

Dual-core

2 processors

Quad-core

4 processors

GPU (Graphics Processing Unit)

Reduces processing required of the system CPU for graphics-intensive processes

Parallel Processing

Distributes processing across multiple processors

Hyper-threading

Single CPU appears as two logical processors

Pipelining

Used to improve performance of a single processor

Heat sink

Metal used to draw heat away from CPU

Cooling fans

Used in desktops to cool electronic components

System Unit

Case that encloses and protects a computer's internal components

Motherboard

Main circuit board of a computer; provides a way for devices to connect to a computer

BIOS (Basic Input/Output System)

A program stored on a chip on the motherboard used to boot the computer

Random Access Memory (RAM)

Temporary (i.e. volatile) storage used by a computer to hold instructions and data while they are in use

Cache Memory

Very fast memory that holds some instructions and data copied from the RAM

USB

Most common type of port, can connect many types of devices

Thunderbolt

Can connect many types of peripheral devices, about the same speed as USB 3.2

Bluetooth

Short-range wireless technology used to connect many types of peripheral devices

Firewire

Legacy port that can connect up to 63 devices to a single port, hot-swappable

Ethernet

Network port used for connecting to networks

CMOS chip

Uses a battery to keep data from being erased when the computer is turned off

L1 (level 1)

fastest and most expensive, built into CPU chip (256KB - 2MB)

L2 (level 2)

a little slower and less expensive, on a separate chip on motherboard (256KB - 8MB)

L3 (Level 3)

slowest and cheapest, but still faster than RAM (4MB - 256MB or more)

Storage Devices

Stores instructions and data when they are not being used.

Non-volatile

Contents not lost when power turned off.

Hard Drive

The primary mass-storage device in most computers.

Flash Memory

A non-volatile form of memory that can be electrically erased and programmed.

Solid-State Drives (SSDs)

Can be used in desktop and notebook computers instead of regular hard drive.

Flash Drives

Also known as USB drives, key drives, thumb drives, or jump drives.

Memory Cards

Used to expand the storage of smartphones, digital cameras, and other devices.

Optical Discs

A laser beam is used to read data.

CDs

About 700 MB.

DVDs

About 8.5 GB.

Blu-ray discs

About 100 GB.

Input Devices

Used to enter data into a computer system.

Keyboard

Most commonly used input device.

Pointing Devices

Moves a cursor on the computer screen (on a GUI).

Optical Scanners

Flatbed scanners - scans a page (or pages) and saves as an image.

NFC Technology

Allows two devices to share data with each other by touching them or bringing them close together.

Output Devices

Devices that present data from a computer.

Monitors

Work by lighting up pixels (picture elements) on the screen.

Resolution

The number of horizontal pixels by vertical pixels, such as 1280×1024.

Ink Jet Printers

Most popular type of personal printer.

Laser Printers

Most common type of business printer.

Dye-Sublimation Printers

High-end printers, mainly used for printing photographs.

Three-Dimensional Printers

Can create objects such as prototypes and models.

Adaptive Technology

Used by individuals with disabilities to interact with technology.

Network Adapters

Can be wired (uses Ethernet cables) and/or wireless (wi-fi).

Analog Modems

Used for dial-up Internet access (uses traditional phone lines).

Cable / DSL Modems

Use for high-speed Internet access.