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)

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

Computer systems Embedded Smartphone Handheld Tablet Netbook Laptop Desktop All-in-One Server Mainframe Super Wearable

Netbook All-in-one Supercomputer Handheld Server Laptop Tablet Smartphone Mainframe Embedded Vehicle Wearable

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

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).

The most popular brand processors on the market are AMD and Intel.

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.

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.

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.

Types of Computer Memory There are two types of memory found on a motherboard: RAM: Random Access Memory ROM: Read-Only Memory RAM chip

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

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.

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

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

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

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.

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.

Caring for Storage Media Keep away from magnetic fields such as those contained in televisions and computer monitors. Avoid Extreme temperatures Remove media from drives and store them properly when not in use. When handling DVD and other optical disc, hold them at the edges. Never try to remove the media from a drive when the drive indicator light is on. Keep discs in a sturdy case when transporting.

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

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.

Standard Input Devices-Keyboard Most commonly used input device. Besides a traditional keyboard, popular types include: Security Foldable or flexible Laser virtual keyboard Gaming Solar Ergonomic Cordless or wireless Specialized Child’s or Toddlers 3535 3535

Keyboards Solar Ergonomic-Split Flexible Blue-Tooth / iPad Child’s Toddler Wireless Gaming Virtual LED-Color Changing

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.

Standard Input Devices (continued) Mouse: Most commonly used pointing device. Types include: Mechanical Optomechanical Optical Wireless Wireless Mouse and Receiver Optical mouse 3838 3838

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

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

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 Magnetic Scanner Image Scanner Bar Code Scanner

Scanner and Digital Camera Optical Character Reader Scanner

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. 4646 4646

Touchpad and Pointing Stick

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 4848 4848

Stylus

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 samples 5050 5050

Fingerprint Scanner

Specialized Input Devices (continued) Remote Controls: An input device used for televisions, lights, and fans as well as for industry and business applications. 5252 5252

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. 5353 5353

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

Liquid Crystal Display (LCD) Monitor

Gas Plasma Display Monitor

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

Inkjet Printer

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. 6161 6161

Plotter

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

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. 6565 6565

Fax Machine

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. 6767 6767