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  COMPUTER CONCEPTS Why Is Computer Literacy Important?Computer literacy  involves having knowledge and understanding of computers and their uses. As computers become more a part of everyday life, many people believe that computer literacy is vital to success. What Is a Computer?  A computer   is an electronic device, operating under the control of instructions stored in its own memory, that can accept data, process the data according to specified rules, produce results, and stores the results for future use. Data  – is a collection of unprocessed items, which can include text, numbers, images, audio, and video. A word data is plural for datum. With respect to computers, however, it is accepted and common practice to use the word data in both the singular and plural context. Inormation - is a processed data that conveys meaning and is useful to people.Example Employees name and address, hourly pay rate, and hours work worked all represents data.  !he computer process the data to produce the payroll check (information) Inormation Processin! Cycle  - eries of input, process, output, and storage activities performed by a computer. Essential elements o Input Processin! Cycle #. Input  – sample are the data$s entered by the user %. Process  – the instructions that the computer performs&. Output  – the information or the results'. Stora!e  – stores the result for future use(. Communication  – computers communication to other computers Instructions  – are the steps that tell the computer how to perform a particular task. What re the Components o a Computer? !he electric, electronic, and mechanical components of a computer, or har#$are , include input devices, outputdevices, a system unit, storage devices, and communications devices. An input #e%ice allows you to enter dataor instructions into a computer. An output #e%ice  conveys information to one or more people. !he system unit  isa case that contains the electronic components of a computer that are used to process data. !he circuitry of thesystem usually is part of or is connected to a circuit board called the motherboard  . A stora!e #e%ice  recordsand)or retrieves items to and from storage media. A communications device enables a computer to send andreceive data, instructions, and information to and from one or more computers. INPUT DE&ICESWhat are the t$o types o input? ã *ata – is a collection of unprocessed text, numbers, graphics, images, audio and video. ã +nstructions - are the steps that tell the computer how to perform a particular task. o rogram – is a series of instructions that tells a computer what to do and how to do it. o ommand – is an instruction that causes a program to perform a specific action. o ser response – is an instruction a user issues by replying to a /uestion displayed by a program ã +nput *evice – is any hardware component that allows users to enter data and instructions into a computer.#. 'ey(oar# ) +t contains keys you press to enter data into the computer.%. Mouse ) +s a small handheld device. With the mouse, you control the movement of a small symbol on thescreen, called the pointer, and you make the selections from the screen.&. Microphone  – allows a user to speak into the computer to enter data and instructions.'. Scanner ) converts printed materials 0such as text and pictures1 into a form the computer can use.(. Di!ital Camera ) you take pictures and then transfer the photographed images to the computer or printer instead of storing the images on traditional film.2. PC &i#eo Camera  – is a digital video camera that allows users to create a movie or take still photographselectronically. Output De%ice  – is any type of hardware component that conveys information to one or more people. o ommonly used output device display devices, printers, speakers and headsets, fax machines and faxmodem, multifunction peripherals, data pro3ectors and force-feedback 3oystick and wheels. OUTPUT DE&ICES #. Printer   – produces text and graphics on a physical medium such as paper.  %. Monitor ) display text, graphics, and videos on a screen.&. Spea*er ) you to hear music, voice and other audio 0sounds1 S+STEM UNIT ) !wo main components on the motherboard   #. Processor or CPU ,Central Processin! Unit-  – is the electronic component that interprets and carries outthe basic instructions that operate the computer.What is the central processing unit 014 ã !he  processor  , also called the central processing unit 01, interprets and carries out the basic instructions that operate a computer.rocessor contains a two components, the control unit   and arithmetic logic unit   that works together to performprocessing operations o ontrol nit – is the component of the processor that directs and coordinates most of the operations in the computer. o  Arithmetic 5ogic nit 0A51 – another component of the processor performs arithmetic, comparison, and other operations.%. Memory ) consists of electronic components that store instructions waiting to be executed and data neededby those instructions. Although some forms of memory are permanent, most memory keeps data andinstructions temporarily, which mean its contents, are erased when the computer is shut off. What is Memory? ã Memory  – consists of electronic components that store instructions waiting to be executed by the processor, data needed by those instructions, and the results of processed data 0information1 o Memory stores three (asic cate!ories o items  !he operatin! system and  other system sot$are  that control or maintain the computer and its devices.  pplication pro!rams  that carry out a specific task such as word processing and resulting information  !he  #ata  being processed by the application program and resulting information. ã 6ytes and Addressable 7emory o .yte 0a character1 – is the basic storage unit in memory. When the application program instructions and data are transferred to memory from storage device, the instructions and data exists as (ytes .  Each byte resides temporarily in a location in memory that has an address . o ##ress  – is a uni/ue number that identifies the location of a byte in memory. /o$ is Memory measure#? ã 7emory i8es o 9ilobyte 096 or 91 – is e/ual to exactly #:%' bytes. o 7egabyte 0761 – is e/ual to approximately # million bytes o ;igabyte 0;61 – e/uals to approximately # billion bytes o !erabyte 0!61 – e/uals to approximately # trillion bytes.!ermAbbreviationApproximate <umber of 6ytesExact Amount of 6ytes Approximate number of ages or !ext9ilobyte96 or 9# thousand#,:%'=7egabyte76# million#,:'>,(?2(::;igabyte;6# billion#,:?&,?'#,>%'(::,:::!erabyte!6# trillion#,:@@,(##,2%?,??2(::,:::,::: ã Types o Memory o &olatile Memory 0 when the computers power off, it loses its content. 0temporary1  Example A7 0andom Access 7emory1 o Non%olatile Memory 0 does not lose its content when power is removed from the computer 0permanent1.  Examples B7 0ead Bnly 7emory1, flash memory, 7B 0omplimentary 7etal Bxide emiconductor1. What is   ran#om access memory ,R M-? ã  Also called main memory . ã onsist of memory chips that can be read from and written to by the processor and other devices. When you turn on power to a computer, certain operating system files 0such as the files that determine how the Windows C desktop appears1 load into A7 from a storage device such as hard disk. !hese files remain in A7 as long as the computer has continuous power. As additional programs and data are re/uested, they also load into A7 for storage. ã !he processor interprets and executes programs instructions while the program is in A7.Dow do computers represent data4  ã !o understand fully the way a computer processes data, you should know how a computer processes data. eople communicate through speech by combining words into sentence. Duman speech is analo! because ituses a continuous 0wave form1 signals that vary in strength and /uality. ã 7ost computers are #i!ital , they recogni8e only two discrete states on  and o  . !his is because computers are electronic devices powered by electricity, which has only two states on and  off. ã !he two digits, : and #, easily can represent these two states. !he digit : represents the electronic state of o , absence   of electronic charge1. !he digit # represents the electronic state of on 0presence of an electronic charge1. ã When people count, they use the digits in the decimal system 0: through @1. !he computer, by contrast, uses a binary system because it recogni8es only two states. o .inary system  – is a number system that has 3ust two uni/ue digits, : and #, called (its .  .it 0 , a   short for binary digit  1 is the smallest unit of data the computer can process. What is   rea#)only memory ,ROM-? ã Rea#)only Memory ,ROM-  – refers to the memory chips storing permanent data and instructions. !he data on most B7 chips cannot be modified – hence, the name read-only. ã ROM is  non%olatile , which means its contents are not lost when power is removed from the computer. +n addition to computers, many devices contain B7 chips. or example, B7 chips in printers contain data for fonts. STOR 1E DE&ICESStora!e Me#ia  – +t is where a computer keeps data, instructions, and information. Example of storage media arefloppy disks, Fip disks,  6 lash drives, hard disks, *s, *G*s, and memory cards. Stora!e De%ice  - ecords 0writes1 and)or retrieves 0reads1 items to and from storage media. *rives and reader )writers, which are types of storage devices, accept a specific kind of stora!e me#ia . +t often functions as a sourceof input because they transfer items from storage to memory.Examples a. * *rive 0storage device1 accepts a * 0storage media1.b. loppy drive accepts a floppy diskc. Fip drive accepts a Fip disk 2loppy #is*  – consists of a thin, circular, flexible disk enclosed in a s/uare-shaped plastic shell that is inserted inand removed from a floppy disk drive 0**1. A typical floppy disk stores up to about 345 million characters46ip #is*  - looks similar to a floppy disk but has much greater storage capabilities – up to about ?(: millioncharacters. Hou insert 8ip disks in and remove them from Fip drives. US. 0niversal erial 6us1  lash #ri%e  - is a portable storage device that has much more storage capacity than afloppy disk but is small and lightweight enough to be transported on a keychain or in a pocket. Hou plug a  6lash *rive in a special, easily accessible opening on the computer 0the  6 port1. /ar# Dis*  - provides much greater storage capacity than a floppy disk, 8ip disk, or  6 flash drive. !he averagehard disk can hold more than >: billion characters. Dard disk is enclosed in an airtight, sealed case. Althoughsome are removable, most are housed inside the system unit Compact Disc  0*1 - is a flat, round, portable metal disc with a plastic coating. !ype of ompact *isc 1. CD)ROM  - which you can access using most * and *G* drives. 2. D&D)ROM  – some of which have enough storage capacity to store two full-length movies. !o use a *G*-B7 you need a *G* drive. *G* 0also known as I*igital Gersatile *iscI or I*igital Gideo *iscI1 What re the Cate!ories o Computers? +ndustry experts typically classify computers in six categories personal computers, mobile computers and mobile devices, midrange servers, mainframes, supercomputers, and embedded computers. ã  A personal computer   is a computer that can perform all of its input, processing, output, and storage activities by itself. !wo popular styles of personal computers o   PC Compati(le  – refers to any personal computer based on the srcinal +67 personal computer design. ompanies such as *ell, ;ateway, Dewlett-ackard, and !oshiba sell -ompatible computers and uses a Windows operating system o   pple  – use a 7acintosh operating system 07ac B 1!wo types of ersonal omputer   o Des*top computers  – is designed so the system unit, input devices, output devices and any other devices fit entirely on or under a desk or table. - ome desktop computers functions as a server   on a network and cost much more than the basic desktop computer. - Wor*station  – another expensive, powerful desktop computer which is geared for work that re/uires intense calculations and graphic capabilities. ã  An architect uses a workstation to design building and home. A graphic artist uses a workstation to create computer – animated special effects for full length motion pictures and video games. o Note(oo* computers  – also called a laptop computer, is a portable, personal computer designed to fit on your lap. -  !hey are thin and lightweight, yet they can be as powerful as the average desktop computer.  And more expensive than desktop computers with e/ual capabilities. - !he keyboard is on the top of the system unit, and the monitor attaches to the system unit with hinges. - Weigh on average between %.( and @ pounds, which allow users easily to transport the computer from place to place. - an operate on batteries or a power supply or both. ã Ta(let PC  is a special type of notebook computer that allows you to write or draw on the screen using a digital pen. o With a digital pen, users write or draw by pressing the pen on the screen, and issue instruction to the !ablet  by tapping on the screen. ã  A mo(ile computer   is a personal computer that you can carry from place to place, and a mobile device is a computing device small enough to hold in your hand. o sually do not have disk drive o our popular types of mobile devices - /an#hel# computers  – 0sometimes a handtop computer1 is a computer small enough to fit on one hand. o creens on handheld computers are small - PD s ,Personal Di!ital ssistant-  – is one of the most popular lightweight mobile devices in uses today. o rovides organi8er functions such as a calendar, appointment book, address book, calculator and notepad. - Smart phones  – is an internet enabled telephone that usually also provides *A capabilities o  Allows you to send and receive e-mail messages and access the web. - Smart $atches  - is an internet enabled watch. +n addition to basic timekeeping capabilities, a smart watch automatically ad3ust time 8one changes, stores personal messages, reminds you of appointments, and wirelessly accesses news, weather, sports and stocks. ã  A mi#ran!e ser%er   is a more powerful and larger computer that typically supports several hundred and sometimes up to a few thousand connected computers at the same time. o !ypically support several hundred and sometimes up to a few thousand connected computers at the same time ã  A mainrame  is a large, expensive, powerful computer that can handle hundreds or thousands of connected users simultaneously and can store tremendous amounts of data, instructions, and information. o tore tremendous amounts of data, instructions, and information. o Every ma3or corporation uses mainframes for business activities ã  A supercomputer   is the fastest, most powerful, and most expensive computer and is used for applications re/uiring complex, sophisticated mathematical calculations. o !he fastest supercomputers are capable of processing more than 377 trillion instructions in a sin!le secon# . o With weights that exceed #:: tons, these computers can store %:,::: times the data and information of an average desktop computer. ã  An em(e##e# computer   is a special-purpose computer that functions as a computer in a larger product. o Embedded computers are everywhere – at home, in your car, and at work. /o$ Is System Sot$are Dierent rom pplication Sot$are?Sot$are , also called a program, is a series of instructions that tells the computer what to do and how to do it.
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