Unit 1 — Computer Basics

Lesson 5 – Input, Output, Storage and Networks Objectives Identify and describe the most common input devices. Identify and describe the most common output devices. Identify and describe how input and output devices are connected to the computer. Lesson 5 – Input, Output, Storage and Networks

Objectives (continued Identify and describe storage devices. List and describe the types of networks. Describe the different network topologies. Describe network architecture and protocols. Lesson 5 – Input, Output, Storage and Networks

Input and Output Devices Input devices enable a user to input data and commands to the computer to be processed. Output devices enable the computer to give or show you the results of its processing. Some devices can perform both input and output operations. Lesson 5 – Input, Output, Storage and Networks

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. Lesson 5 – Input, Output, Storage and Networks

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. Lesson 5 – Input, Output, Storage and Networks

Other 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: This is like a mouse turned upside down. You roll a ball around with your fingers to control the location of the pointer. These are frequently found on notebook computers. Lesson 5 – Input, Output, Storage and Networks

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. Lesson 5 – Input, Output, Storage and Networks

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. Video input from a camcorder or VCR can be input using video capture cards. Digital cameras take pictures and store them on a magnetic disk instead of on film. Their images can be input directly into the computer. Lesson 5 – Input, Output, Storage and Networks

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. Lesson 5 – Input, Output, Storage and Networks

Typical Computer Monitor This figure shows a typical computer monitor on a swivel stand that can be adjusted for viewing comfort. A few years ago, monitors with a diagonal mea-surement of 13” were standard on computer systems, but today 15”, 17”, 19”, and even larger screens are becoming the norm. Notebook computers usually use a flat-panel display built into the lid of the notebook case. Lesson 5 – Input, Output, Storage and Networks

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. Dot matrix: These work similarly to a typewriter in that ink is transferred to the paper by some part of the printer striking a ribbon to transfer an image. Lesson 5 – Input, Output, Storage and Networks

Laser Printer Operation This figure provides an overview of how a laser printer works. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Ink-Jet Operation This figure shows how an ink-jet printer works. Lesson 5 – Input, Output, Storage and Networks

Connecting I/O Devices to the Computer Input and output devices must be connected to the printer before they can be used. There are two ways to connect I/O devices to the computer: Plug the device into an existing socket or port on the back of the computer. Install an expansion card with the port you need included on the back of the card. Lesson 5 – Input, Output, Storage and Networks

Serial, Parallel, and Special Ports Serial ports transmit data one bit at a time and are used to connect a mouse, modem, and keyboard. Parallel ports transmit data 8 bits at a time and are used for printers and external storage devices. There are also special ports: SCSI: This port can allow many devices to use a single port. MIDI: Used to connect recording devices. PC card: Can be connected to add memory or storage capacity. USB: Can be used to replace serial and parallel ports and can handle up to 127 devices. Lesson 5 – Input, Output, Storage and Networks

Storage Devices - Magnetic There are many types of magnetic storage devices, including Floppy disks: Small, portable disks that hold a limited amount of data. Hard disks: Large-capacity and fast-access storage devices. Zip and Jaz drives: Auxiliary storage devices that can hold large quantities of data and can be portable. Magnetic tape drives: Used for making system backups and storing large quantities of data. Lesson 5 – Input, Output, Storage and Networks

Optical Storage Devices 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. WORM disks: Used for permanently storing large amounts of data. Photo-CD: Used for storing digital photographs on a CD. DVD: This is the size of a CD, but can hold much more data, including full-size movies. Lesson 5 – Input, Output, Storage and Networks

Caring for Removable Storage Media To safeguard your data from damage, follow these tips when dealing with removable media: Keep away from magnetic fields. Avoid extreme temperatures. Never try to disassemble the case. Remove media from drive when not being used. Write-protect important data. Hold optical disks at their edges. Never remove the media from the drive if the access light is on. Keep disks in a sturdy case when transporting them. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Introducing Networks A network is a group of two or more computers linked together. Most networks have a server which manages the network resources. Most networks have multiple clients, which are computers that access the server. A network confined to a limited geographical area is called a local area network (LAN). A network spread over a wide area is called a wide area network (WAN). The transmission of data from one location to another is called data communications. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Data Communications This figure shows the main components required for data communications: A sending device, a receiving device, a communication path or channel, a device to convert the signal so that the channel can carry it, and the soft-ware to send and receive messages. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Network Benefits Networks provide almost instant communication with other users on the network. Users can share information. Users can share hardware. Users can share software. Users can work on group projects. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Communications Media Sending data from one computer to another requires a channel, the link through which the message is sent. A phone line or cable is a channel. You need a device on each end of the channel to convert the computer signal to a signal type that the channel can send. Sending a message through the channel requires a transmission media, which can be physical or wireless. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Physical Media Physical media types include Twisted-pair cable Coaxial cable Fiber optic cable Wireless media types include Radio signals Microwaves Satellites Lesson 5 – Input, Output, Storage and Networks

Physical Media Examples Coaxial Fiber optic Twisted pair Lesson 5 – Input, Output, Storage and Networks

Wireless Media Examples Microwaves Satellites Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Network Hardware Most networks consist of a server and multiple client computers. They also include two other categories of hardware: Communications hardware These devices facilitate the transmitting and receiving of data. Network transmission hardware These devices connect the cabling and amplify signals as they travel across the network. Lesson 5 – Input, Output, Storage and Networks

Communications Hardware Modems: Convert analog signals to digital and vice versa. Modems enable a computer to send data over a standard phone line. The sending computer and the receiving computer must both have modems. Cable modems: Use coaxial cable to send data over cable TV lines. These have much faster transmission rates than a standard telephone line modem. Lesson 5 – Input, Output, Storage and Networks

Network Transmission Hardware Network Interface Cards (NICs) All PCs in a LAN must have a NIC. Hub Receives and sends signals back out Bridge Connects one LAN to another LAN Gateway Links networks using different protocols Router Connects multiple networks and determines the fastest route for sending data over the network Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Types of Networks Local area networks (LANs) are usually confined to a limited area. The two most popular LANs are Client/server Peer-to-peer Wide area networks (WANs) are spread across a city, a state, the country, or the world. Most WANs consist of two or more LANs connected by routers. Some WANs may be configured as intranets or extranets. Lesson 5 – Input, Output, Storage and Networks

Client/Server vs. Peer-to-Peer Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Network Topologies A topology is the geometric arrangement of the network. The most common topologies are Bus: All devices are connected to a master cable. Ring: Similar to a bus except that the devices are connected in a circle. Star: All devices are connected to a central hub or computer. Lesson 5 – Input, Output, Storage and Networks

Example of Bus Topology Lesson 5 – Input, Output, Storage and Networks

Example of Ring Topology Lesson 5 – Input, Output, Storage and Networks

Example of Star Topology Lesson 5 – Input, Output, Storage and Networks

Communications Protocols A protocol is a set of rules that allows computers to exchange data. The protocol determines How a sending device indicates it has finished sending. How a receiving device indicates the message was received. The type of error checking to use. The most common protocols are Ethernet: Most common LAN protocol. Token ring: Also used on LANs. TCP/IP: Used on the Internet. Lesson 5 – Input, Output, Storage and Networks

Network Operating Systems Software Networks require a network operating system (NOS) and a desktop operating system. The clients run the desktop OS. The NOS runs on the server and provides Network administration tools Print services Client services Security services Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Summary The most common input devices are the keyboard and mouse. The keyboard is divided into four sections: alphabetical keys, function keys, cursor keys, and the numeric keypad. Additional special-purpose keys perform specialized functions. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Summary (continued) The mouse is a pointing device used to input data. Input devices enable you to input data and commands into the computer. Other types of input devices include joysticks, trackballs, graphic tablets, touch display screens, voice recognition devices, scanners, and electronic pens. Printers are used to produce a paper or hard copy of the processed result. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Summary (continued) Criteria for selecting a printer include speed, print quality, and cost. Printers are classified as either impact or non-impact. The most popular types of printers are laser, ink-jet, and dot matrix. Input and output devices must be physically connected to the computer. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Summary (continued) There are two ways to connect I/O devices to a computer: Plug the device into a port in the back of the computer or install a circuit board with the needed port included. There are several types of ports: USB, SCSI, MIDI, parallel, and serial. To maintain a permanent copy of data, you must store it on some type of storage medium. These may include floppy diskettes, hard drives, CDs, magnetic tape cartridges, and WORM disks. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Summary (continued) A network is a group of two or more computers linked together. A local area network is generally confined to a limited geographical area. A wide area network is made up of several connected local area networks. Data communications is the transmission of data from one location to another. The Internet is the biggest network of all. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Summary (continued) You can use a network for information sharing, hardware or software sharing, and as a collaborative environment. The link through which data is transmitted is the communications channel. Transmission media can be either physical or wireless. Physical media includes twisted-pair cable, coaxial cable, and fiber optic cable. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Summary (continued) Wireless media includes radio signals, microwaves, and satellites. Most networks consist of a network server and computer clients. A modem is a type of communications device. Network interface cards enable the sending and receiving of data between the PCs in a LAN. A hub is a device that controls the incoming and forwarding of data. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Summary (continued) A gateway links two different types of networks. A router directs the Internet or LAN traffic. The two popular types of LANs are the client/ server network and peer-to-peer. Network topologies include bus, ring, and star. A protocol is an agreed-on set of rules and procedures for transmitting data between two or more devices. Lesson 5 – Input, Output, Storage and Networks

Lesson 5 – Input, Output, Storage and Networks Summary (continued) The Ethernet is one of the most popular LAN protocols. Token ring is the second most widely used LAN protocol. TCP/IP is a protocol used by both LANs and WANs to connect to the Internet. All computers require an operating system. Networks require network operating systems. Lesson 5 – Input, Output, Storage and Networks