Chapters 4 & 5: Computer Hardware and System Software

Hardware

Refers to the physical components of a computer

CPU (Central processing unit)

"Brain" of the computer, housed on the motherboard in the system unit, processes commands (from software), controls functions performed by other components

Hardware

Refers to the physical components of a computer

CPU (Central processing unit)

"Brain" of the computer, housed on the motherboard in the system unit, processes commands (from software), controls functions performed by other components

Control unit

Executes instructions

Arithmetic logic unit (ALU)

Performs calculations

Instruction Cycle

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

Clock speed

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, increases processing speed over a single-core processor, reduces energy consumption over multiple separate processors

Dual-core

2 processors

Quad-core

4 processors

GPU (Graphics Processing Unit)

Reduces processing required of the system CPU for graphics-intensive processes, found on a video card

Parallel processing

Distributes processing across multiple processors, typically each process (program) is assigned to a processor by the operating system

Hyper-threading

Can be simulated to allow a single CPU to appear as two logical processors

Pipelining

Used to improve performance of a single processor, allows a single processor to process up to 4 instructions at the same time

Cooling System

Electronic components, especially processors, generate heat and need to be kept cool to prevent them from burning out

Heat sink

Metal used to draw heat away from CPU

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

Ports

Used to connect peripheral devices to the motherboard

USB

Most common type of port, can connect many types of devices, can connect up to 127 devices to a single port, hot-swappable

Thunderbolt

Can connect many types of peripheral devices, can connect up to six devices using one port, hot-swappable

Bluetooth

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

BIOS (Basic Input/Output System)

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

Random access memory (RAM)

Temporary (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 to improve performance

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

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

Aka 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

Laser beam is used to read data.

CD

About 700MB.

DVD

About 8.5GB.

Blu-ray Disc

About 100GB.

Input Devices

Used to enter data into a computer system.

Keyboard

Most commonly used input device.

Mouse

Most common pointing device.

Optical Scanners

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

NFC

Near field communication technology allows 2 devices to share data with each other by touching them or bringing them close together.

Monitors

Work by lighting up pixels on the screen.

Resolution

Number of horizontal pixels by vertical pixels, such as 1280x1024.

CRT Monitors

Big, bulky, heavy legacy technology.

LCD Monitors

Thinner, lighter, originally developed for portable computers.

Inkjet Printers

Most popular type of personal printer that sprays droplets of liquid ink onto paper.

Laser Printers

Most common type of business printer using a powdered ink cartridge.

Dye-sublimation Printers

High-end printers, mainly used for printing photographs.

Multifunction Devices

Printer with a built-in scanner and sometimes fax capabilities.

Adaptive Technology

Used by individuals with disabilities to interact with technology.

Network Interface Cards (NICs)

Can be wired (uses Ethernet cables) and/or wireless (wifi).

Analog Modems

Used for dial-up internet access.

Operating System (OS)

Low-level software that controls the computer hardware.

User Interface (UI)

Determines how the user interacts with the computer.

Single-tasking OS

Only one program can be executed at a time.

Multi-tasking OS

Multiple programs can be executed at the same time.

Virtual Memory

Allows users to open up more applications and data files than can physically fit in the computer's memory.

Device Drivers

Small programs used for the operating system to communicate with peripheral devices.

APIs

Application Programming Interface allows application programs to call API functions to have the operating system perform low-level tasks.

Desktop Operating Systems

Examples include MS-Windows, Mac OSX, and Linux.

Current OS

Windows 11

Previous Windows versions

Windows 3.1 were NOT operating systems, but application programs that ran on MS-DOS

Market share of Windows

Most popular OS (~73% of desktops/portable run some version of Windows)

Windows stability and security

Considered to be less stable (i.e. crashes more often) and less secure (i.e. higher probability of being infected with computer virus) than Mac OSX

Cost comparison

Windows systems are much less expensive than Macs

Mac OS release year

Originally released in 1984

Mac OS

(almost) first commercial computer to use a GUI

Mac OS cost comparison

Much, much more expensive than MS-DOS/MS-Windows computers of the time

Mac OSX release year

First released in 2001

Mac OSX characteristics

Completely new OS (based on UNIX and NeXTStep) and hardware

Mac OSX stability and security

Considered more stable (less likely to crash) and more secure (less likely to be infected with a computer virus) than Windows

Mac OSX cost comparison

More expensive (often by 1.5-3 times) than Windows computers

Mac OSX market share

~14% market share

Linux characteristics

Open Source, can download for free, including source code

Linux versions

Multiple versions (Red Hat, Ubuntu, openSUSE, ChromeOS, etc.)

Linux market share

~2% market share

Configuring MS-Windows

Control panel/Settings Window

Configuring MacOSX

System Preferences

Standard account

A type of user account

Administrator account

A type of user account with elevated privileges

Embedded Operating Systems

Specialized OS that runs in various electronic devices, very small, normally fits on a single chip

Examples of Embedded OS

GPS devices, ATMs, sensors, microwave ovens, thermostats, etc.

Mobile Operating Systems

Operating systems that run on mobile devices such as smartphones and tablets

Apple iOS characteristics

Scaled down version of MacOSX used in iPhones and iPads, proprietary - found on Apple devices

Google Android characteristics

Open source, scaled down version of Linux, found in devices from many companies

Networking Operating Systems (NOS)

Used in client-server networks, multi-user operating system that controls the software and hardware running on a network

Unix characteristics

The oldest and most powerful operating system (early 1970s), with over 200 commands, has reputation for being hard to learn

Peer-to-Peer Network

Type of network normally used at home where each computer/device is considered equal

Utility Software

Type of system software used to perform computer maintenance

Disk Formatting Utility

Prepares a hard disk to store files by setting up the file system, only needs to be done once

Security utilities

Includes firewall, antivirus program, and antispyware program

Troubleshooting

Reboot is the most common 'solution' when something goes wrong