Hardware

A computer is device that . . .

Uses stored instructions (programs) Accepts data that user supplies (input) Manipulates data according to a program

(processing) Stores data (storage) Produces results (output)

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Common System Components

This figure shows several devices that are common components of a computer system.

Computer system vs. System unit

Computer system—the system unit along with input and output devices

System unit—the part of a computer system that processes data and stores information

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Embedded Smartphone Handheld Tablet Netbook Laptop

Desktop All-in-One Server Mainframe Super Wearable

Computer systems

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Handheld

Smartphone

Netbook

Tablet

All-in-one

Supercomputer

Wearable

Server

Embedded Vehicle

Laptop

Mainframe

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The Motherboard

The motherboard is a circuit board inside the microcomputer’s plastic case. It contains integral components including The central processing unit or CPU Basic controllers Expansion ports and slots Memory

Motherboard

Computer System Components

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The Central Processing Unit

The CPU executes commands from a computer's hardware and software; the principal computer chip that contains several processing components, which determines the computer's operating speed; the "brain" of a computer

The system clock is an electronic pulse that controls the speed of the CPU. The rate of the pulse is measures in gigahertz (GHz).

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The most popular brand processors on the

market are AMD and Intel.

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The Central Processing Unit (continued)

The CPU has two primary sections: The Arithmetic/Logic Unit (ALU)

This section performs arithmetic and logical operations.

The Control Unit This section coordinates all activity

within the CPU. It uses programming instructions to control what actions the CPU performs and when it performs them.

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A CPU Chip

This figure shows a CPU chip for a small computer. The CPU determines which of the millions of switches that it contains should be turned on or off by processing program statements that tell it what to do.

Computer programs are written in programming languages, and each program statement causes one or more actions to occur in the CPU.

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Types Computer Memory

Data being processed by a CPU is stored in system memory.

Memory are computer chips that store data and programs while the computer is working.

Data stored in memory is not permanent. If the power fails, everything in memory is lost.

Data must be stored on a disk or some other device when not being processed so it is not lost each time the computer shuts down.

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Types of Computer Memory

There are two types of memory found on a motherboard:

RAM: Random Access Memory

ROM: Read-Only Memory

RAM chip

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Random Access Memory (RAM)

RAM is short-term memory where data is processed while a program is running.

Data stored here can be accessed and modified as needed.

This type of memory loses any data it holds if the computer is shut down.

RAM is also called main memory.

RAM Chips

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Read-Only Memory (ROM)

ROM is memory placed on the motherboard by the manufacturer and contains instructions, such as BIOS ROM, that tell the computer how to start itself.

This data cannot be accessed or modified by application programs.

The contents of this memory are not lost when the computer is shut down.

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Storage Devices

If you want to keep a permanent copy of data, you must store it on some type of storage medium.

Storage Device are external hardware used to store and retrieve data such as disk drive, CD/DVD drive, flash drive, or tape drive.

Storage devices are categorized by the method they use to store data, including magnetic, optical, and solid state storage devices.

A computer is . . .

A purely digital device Definition: Digital is a type of electronic

signal that is processed, sent and stored in bits—binary digits

Computers use binary coding—a coding system that uses two numbers--1 & 0

In computer terms, the bit is the smallest unit of measurement a computer can understand

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Bits to bytes . . .

8 bits equal 1 byte A byte is a single character of data,

such as a letter, number, etc. Kilobyte—one thousand bytes of data Megabyte—one million bytes Gigabyte—one billion bytes Terabyte—one trillion bytes

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Storage Devices - Magnetic

There are many types of magnetic storage devices, including

Floppy disks: Small, portable disks that hold a limited amount of data. (1.44 MB)

Hard disks: Large-capacity and fast-access storage devices. (Measured in gigabytes or terabytes)

Magnetic tape drives: Used for making system backups and storing large quantities of data.

Hard Disk

Floppy Disks

Magnetic Tape

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Storage Devices - Optical

There are several optical storage devices in use today, including

CD-ROM: Can hold large amounts of data, but is read-only access.

CD-R: This drive allows you to read and to write to a compact disk.

CD-RW: This drive allows you to read and write to a compact disk several times.

DVD: This is the size of a CD, but can hold much more data, including full-size movies

Blu-Ray – Next generation of optical disc format; provides more than 5 times the storage capacity of traditional DVD’s.

Laser Reads CD or DVD

Flash Drive or Quick Drive

A small portable device that is capable of storing digital contents such as images, documents and other kinds of files.

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Network Drives

A network drive is located on another computer or a server where space is provided for storage of data from many computer terminals.

Network drives may appear as the Q:\ or R:\ drive on a terminal to distinguish it from the drives that are part of the computer terminal. Our network drive is M:\.

Online Backup

Online backup is a method of offsite data storage in which files, folders, or the entire contents of a hard drive are regularly backed up on a remote server or computer with a network connection.  

User may pay fee for this type of service or it may be free.

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Caring for Storage Media

1. Keep away from magnetic fields such as those contained in televisions and computer monitors.

2. Avoid Extreme temperatures3. Remove media from drives and store them

properly when not in use.4. When handling DVD and other optical disc,

hold them at the edges.5. Never try to remove the media from a drive

when the drive indicator light is on.6. Keep discs in a sturdy case when

transporting.

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Input and Output Devices

Input devices data entered into the computer through a variety of devices such as keyboards, microphone, scanner, flash drive or mouse.

Output devices allows a user to view or listen to the data a computer processes such as a monitor, printer, headphones, or speakers.

What types of data . . . ?

Text data – letters, numbers, and special characters

Graphic data – photographs, charts, and drawings

Audio data – voice and music Video data – moving pictures and

images

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Input Devices – The Keyboard

The keyboard is the most common input device. As you press keys on the keyboard, an electrical

signal representing that key is sent to the computer.

Keyboards are divided into sections: Typewriter keys: The standard alphabetic and

numeric characters you would find on a typewriter.

Function keys: Special keys that perform some specific function for the application being run.

Numeric keypad: Used for mathematical operations.

Directional keys: Used to move the cursor around the screen.

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Standard Input Devices-Keyboard

Most commonly used input device. Besides a traditional keyboard, popular types include:

– Ergonomic– Cordless or

wireless– Specialized– Child’s or

Toddlers

– Security– Foldable or

flexible– Laser virtual

keyboard– Gaming– Solar

Keyboards

Solar Ergonomic-Split

Flexible

Blue-Tooth / iPad

Ergonomic-Split

Child’s Toddler Wireless

Gaming

Virtual

Virtual

LED-Color Changing

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Input Devices – The Mouse

The mouse is a pointing device that rolls around on a flat surface and controls the location of the pointer on the screen.

The mouse performs the following functions: Pointing: Place the on-screen pointer at a specific

place. Clicking: Press and release the mouse button. Dragging: Holding down the mouse button and

dragging an object to a new location by dragging the mouse.

Double-clicking: Pressing and releasing the mouse button twice very quickly.

Right-clicking: Pressing the right mouse button.

Mouse: Most commonly used pointing

device. Types include:

Standard Input Devices (continued)

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– Mechanical– Optomechanical– Optical– Wireless

Optical mouse

Wireless Mouse and Receiver

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Other Input Pointing Devices

In addition to the mouse, there are other devices that control the on-screen pointer, including a Joystick: Joysticks consist of a metal or plastic

handle mounted on a base that you can move in any direction to move the pointer or other object.

These are typically used for video games. They frequently have buttons that can be

pushed or clicked to control input/output. Trackball: A pointing device that works like a

mouse turned upside down; the ball is on top, operated by your thumb and fingers.

These are frequently found on notebook computers.

Trackball and Joystick

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Trackball Joystick

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Other Input Devices (Part I)

A graphic tablet is a flat drawing surface connected to the computer. The user draws on the surface, and the

figures or writing on the tablet can be input to the computer for processing.

Touch display screens contain pictures or shapes that the user can press to input that information.

Voice recognition devices allow a user to speak to a computer and have their words input to an application program. These usually require a microphone and

special voice recognition software to be installed on the computer.

Graphics Tablet and Touch Display Screen

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Graphics Tablet Touch Display Screen

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Other Input Devices (Part II)

Scanners are devices that can convert a graphical image into a digital image and input it to the computer. Types of scanners include

Image scanners for scanning images and text. Bar code scanners to read product bar codes. Magnetic scanners to read the magnetic strip on a credit

card. Optical Character Reader (OCR) reads handwritten or

typed text. Optical Mark Reader – reads “bubble” sheets marked with

pencil Video input from a camcorder or VCR can be input using

video capture cards. Digital cameras takes pictures are stored digitally and then

transferred to the computer’s memory. Their images can be input directly into the computer.

Scanners

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Image Scanner

Bar Code Scanner

Magnetic

Scanner

Scanner and Digital Camera

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Optical Character Reader Scanner

Digital Camera

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Standard Input Devices (continued)

Touchpad: Common feature on laptops; a specialized

surface that converts the motion and position of your fingers to a position on the screen.

Pointing Stick: A pressure-sensitive device located on

the keyboard of many notebook computers and moved with the forefinger.

Touchpad and Pointing Stick

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Touch Pad Pointing Stick

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Standard Input Devices (continued)

Stylus: Pen-like writing instruments to input

information to a PDA or other mobile device.

Environmental Probes and Sensors: Used with a Web browser to monitor

elements of the work area such as humidity, pollution, or security

Stylus

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Specialized Input Devices (continued)

Security Devices: Biometric devices consist of a reader

or scanning device and software that converts the scanned information (finger prints, retinas, facial recognition) into a digital format.

The way biometric technology works: Enrollment: User establishes baseline

measurement Submission: User presents proof of identity Verification: System compares samples5

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Fingerprint Scanner

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Remote Controls: An input device used for televisions,

lights, and fans as well as for industry and business applications.

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Specialized Input Devices (continued)

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Specialized Input Devices (continued)

Virtual Devices: Use the synchronized positioning of

light-emitting and sensing devices to detect user input; for example, a virtual computer keyboard.

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Output Devices - Monitors

Monitors are used to display video output to a user.

Monitors may be monochromatic or color. Monochromatic monitors display output in a

single-color display. Factors that influence the quality of a monitor are

Screen size: The diagonal measurement in inches of the display area.

Resolution: The number of pixels that can be displayed in the display area.

Dot pitch: The distance between each pixel in the display area.

Cathode Ray Tube (CRT) Monitor

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Liquid Crystal Display (LCD) Monitor

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Gas Plasma Display Monitor

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Output Devices - Printers

Printers are used to create a hard copy of a document or image. Printers vary by speed, quality, and price.

The most popular types of printers are Laser: Produce images using the same techniques as

copier machines. Ink-Jet: These use fine nozzles to spray ink onto the

page as the paper passes through. The speed of a printer is measured by the number of

pages per minute (PPM) that can be printed The quality of a printer is measured by the number of

dots per inch (dpi) that can be printed

Laser Printer

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Inkjet Printer

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Specialized Output Devices (continued)

Specialized Printers: Line printer: High-speed printer attached

primarily to large computers. Thermal: Forms characters by heating paper. Mobile: Small, battery-powered printer. Label and postage: Prints labels, including

postage, on adhesive-type paper. Plotters are printers that use pens to draw

lines to create maps, charts, and blueprints. used by engineers, architects, and artists.

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Plotter

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Other Output Devices

Multifunction printer: Combines various output options such as printing, scanning, and copying.

Projectors are used to project a large image of what is on the computer screen.

Speakers allow you to hear recorded music or speech from your computer.

Multifunction Printer, Projector, and Speaker

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Multifunction Printer

Projector Speaker

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Specialized Output Devices

Fax machines and fax modems: Transmit and receive documents through phone lines or computer.

Control devices/robots: Robotics is the study, design, and use of robot systems for manufacturing.

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Fax Machine

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Specialized Output Devices (continued)

Output Devices for the Physically Challenged:

Various special devices are available: Screen magnifiers: Enlarge information on

the computer screen. Screen readers: Use speech synthesizers to

read content for people who are blind or visually impaired.

Voice synthesizers: A voice changes written computer text into synthetic speech.

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