Output Devices PDF

Created by Turbolearn AI What is Output? Output Data The data that has been processed into useful information is called output. The output may consist of text, graphics, audio, or video. Types of Output vs Type Description Characteristics...

Created by Turbolearn AI What is Output? Output Data The data that has been processed into useful information is called output. The output may consist of text, graphics, audio, or video. Types of Output vs Type Description Characteristics Not tangible, electronic form, easier to modify, Output shown on a Softcopy intangible, stored on storage devices, inexpensive display screen. duplicates, transferable electronically Tangible, printed form, difficult to modify, tangible, Output printed on Hardcopy printed on paper, costly duplicates, transferable paper. physically Output Devices The hardware components that are used to receive information from the computer are called output devices. Output devices take information from the computer and convert it into a form understandable by users. Some important output devices are: Monitors Printers Plotters Speakers Display Screen Features Size Page 1  Created by Turbolearn AI The size of a display screen is measured diagonally. Desktop computer monitors range from 17 to 30 inches, but larger ones are available. Laptop screens are usually 14 to 17 inches. Tablet screens are between 7 and 10 inches. Color Display screens can be monochrome (single color) or color. Color displays use RGB (Red, Green, Blue) to create a wide range of colors. Monochrome displays typically show white, green, blue, red, or amber, but can display different shades of a single color. Resolution The number of pixels (dots) displayed on the screen is called screen resolution. Higher pixel counts mean sharper images. Video Display Adapters VGA (Video Graphics Array): Uses 4-bit color, supports 16 to 256 colors depending on resolution. SVGA (Super Video Graphics Array): Uses 8-bit color, supports 256 colors at higher resolution than VGA. XGA (Extended Graphics Array): Uses 24-bit color ("true color"), supports up to 16.7 million colors. Types of Display Screens CRT Monitor An older type of display screen resembling a television. It's large, heavy, bulky, uses more energy, and emits harmful radiation. It uses a Cathode Ray Tube (CRT) to display images. Color CRT monitors use three guns generating red, green, and blue (RGB) colors. Flat Panel Displays Page 2  Created by Turbolearn AI These take less space, are lightweight, consume less power, but are more expensive than CRTs. Three types of technologies are used: Liquid Crystal Display (LCD): Uses liquid crystals to block or allow light. Electroluminescent Display (ELD): Uses a substance that glows when charged by electric current. Gas Plasma Display: Similar to a neon bulb; uses a gas that emits light with electric current. More expensive and typically used in larger displays. CRT vs LCD Monitors Feature CRT Monitor LCD Monitor Cost Less expensive More expensive Desk Space Takes more Takes less Energy Use Uses more Uses less Technology Picture tube Liquid crystal Weight Heavier Lighter Harmful Radiation Emits harmful radiation Does not emit harmful radiation Printers A printer is an output device that prints characters, symbols, and graphics on paper. Print quality depends on resolution (dots per inch or dpi). Impact Printers Works like a typewriter; prints by striking a print hammer or pins against an inked ribbon. Older technology, used where low-cost printing is required. Types include: Dot Matrix Printers Daisy Wheel Printers Line Printers Non-Impact Printers Page 3  Created by Turbolearn AI Prints without striking the paper; uses spray ink, heat, or pressure. Faster and quieter than impact printers, but more costly and with better print quality. Types include: Laser Printers Inkjet Printers Thermal Printers Impact Printers in Detail Dot Matrix Printer Uses tiny pins on a print head to strike an inked ribbon, creating dots that form characters and graphics. Speed is measured in characters per second (cps). Does not provide high-quality output and is noisy. Daisy Wheel Printer Uses a wheel (daisy wheel) with characters on each petal. A hammer strikes a petal against the ribbon to print. Line Printer Prints an entire line at a time; speed measured in lines per minute (lpm). Used by mainframe and minicomputers. Non-Impact Printers in Detail Laser Printer Uses laser beams and toner to create images on a page. Prints a complete page at a time (page printer). Speed is measured in pages per minute (ppm). Printer Types Page 4  Created by Turbolearn AI Laser Printer A laser printer prints text and graphics in high-quality resolution (1200 dpi or more). It's faster and quieter than inkjet and dot matrix printers, commonly used in business. Inkjet Printer An inkjet printer is a non-impact printer that sprays tiny ink drops onto paper. It produces quality text and graphics, in color and black and white, including photos (typical resolution 300 dpi, but higher resolutions are available). Printing speed is measured in pages per minute (ppm), typically 10-35 ppm, with graphics and colors slower than text. Inkjet printers are less expensive than laser printers but slower. Thermal Printer A thermal printer uses heat and color waxes to produce images on special paper (no wax needed for black and white). They are expensive and require costly paper but produce high-quality color printing. Plotter A plotter prints high-quality graphics in various colors, typically used for large posters, graphs, maps, and engineering drawings. Plotters are more expensive than printers. Data Encoding Computers use binary numbers (0s and 1s) to store data. Encoding is the process of converting data into binary form. Several coding schemes exist: Types of Coding Schemes Page 5  Created by Turbolearn AI Coding Bit Description Use Scheme Size Binary Coded Decimal; each decimal digit is BCD 4 Early computers represented by 4 bits Extended Binary Coded Decimal Mainframe EBCDIC 8 Interchange Code; 8-bit code computers American Standard Code for Information ASCII Interchange; 7-bit (128 characters), 7/8 Personal computers extended 8-bit (256 characters) Represents 16-bit code (65,536 characters); replacing Unicode 16 characters from all ASCII languages Data Transmission Modes Simplex Mode Data flows in only one direction, like a one-way street. A device can either send or receive, not both. Example: Traditional television broadcast. Half-Duplex Mode Data flows in both directions, but not simultaneously. Transmission is one-way at a time. Example: Internet surfing (requesting a webpage, then waiting for it to download before making another request). Full-Duplex Mode Data flows in both directions simultaneously. Faster than half-duplex. Example: A telephone conversation (both people can talk at the same time). Types of Data Transmission Parallel Transmission Page 6  Created by Turbolearn AI Multiple bits are sent simultaneously over separate lines. Faster than serial transmission; commonly used for internal data transfer in computers and between computers and printers. Usually unidirectional. Serial Transmission Bits are sent sequentially, one bit at a time. Slower than parallel transmission; used in telephone lines. Asynchronous and Synchronous Transmission Asynchronous Transmission Data is transmitted character by character; the time interval between characters isn't consistent. Less efficient and slower than synchronous transmission. Uses start (value 0) and stop (value 1) bits to mark the beginning and end of each character. Synchronous Transmission Data is transmitted block by block; the time interval between characters is consistent. Faster than asynchronous because there are no gaps between characters; uses a clock for timing. Suited for remote communication between computers and devices. Bandwidth and Communication Channels Bandwidth is the amount of data that can be transferred through a communication medium per unit of time (bits/second or bytes/second for digital signals; cycles/second or Hertz for analog signals). Baseband A technique where digital signals are transmitted directly on the transmission line without modulation. Only one signal is transmitted at a time. Page 7  Created by Turbolearn AI Broadband A technique for transmitting large amounts of data (voice and video) over long distances. Multiple signals are transmitted simultaneously using Frequency Division Multiplexing (FDM), which divides the bandwidth into smaller frequency bands. Faster than baseband. Communication Channels/Media The path for data transmission. Guided Media (Bounded Media) Devices are connected by physical media like wires. Twisted Pair: Inexpensive, easy to install, short-distance transfer. Coaxial Cable: A copper wire covered by insulating material. Fiber Optic: Uses light signals for transmission. Unguided Media (Unbounded Media) Devices communicate through air or space. Microwave Communication Satellite Communication Mobile Communication Lecture Notes: Computer Networks & Systems Guided Transmission Media Coaxial Cable Page 8  Created by Turbolearn AI More expensive than twisted pair. Higher data transfer rate than twisted pair. Easy installation. Uses copper mesh to protect data signals from electromagnetic interference. Used by cable TV networks and telephone companies. Fiber Optic Cable Transmits data as pulses of light through glass tubes. Consists of a core (where light travels), cladding (reflects light back into the core), and a protective plastic jacket. Used by telephone companies, ISPs, and cable TV operators. Advantages: Very high speed. High information carrying capacity. Lighter and smaller. More secure and reliable. Unaffected by electromagnetic waves. Disadvantages: Difficult to install. Expensive. Unguided Transmission Media Microwave Communication Uses radio waves for high-speed transmission of voice and data. Uses line-of-sight transmission (signals travel in straight paths). Stations are typically installed on high towers or buildings, spaced 20-30 miles apart. Susceptible to interference from buildings or mountains. Communication Satellites Page 9  Created by Turbolearn AI Used for wireless communication over large distances. Satellites are positioned about 22,300 miles above the earth. Uplink: Transmission from earth station to satellite. Downlink: Transmission from satellite to earth station. Advantage: Large volume of data transmission. Disadvantage: Susceptible to bad weather. Mobile Communication Radio-based network for data transmission to and from mobile computers. Widely used globally. Computer Systems Fundamentals Data vs. Information Data: A collection of raw, unprocessed facts and figures. Information: Processed data; organized and more meaningful. Data Processing The process of converting data into information. Input → Processing → Output Software and Hardware Software: A set of instructions (programs) given to the computer. Hardware: The physical components of the computer. Software and hardware are interdependent; one cannot function without the other. Primary Components of a Computer System Page 10  Created by Turbolearn AI Component Function Examples Input data and instructions into the Input Devices Keyboard, mouse computer. Processing Unit Processes data. Central Processing Unit (CPU) (CPU) Holds data, instructions, and Main Memory RAM results temporarily. Output Devices Display the results of processing. Monitor, printer Store data and programs Hard disk drive, USB flash Storage Devices permanently. drive, CD/DVD Types of Software System Software Programs that control and manage computer hardware and operations. Examples: Operating Systems, Utility Programs, Device Drivers. Application Software Used to perform specific tasks. Categories of Application Software Customized Software: Designed for a specific customer or organization. Package Software: Developed for general sale to the public (e.g., MS Word, MS Excel). Operating System (OS) A set of programs that manages computer components and operations. Acts as an interface between the user and the hardware. Examples: Microsoft Windows, Linux, macOS. Page 11