Computer Hardware Essay

I. call down OVERVIEWFoundation Concepts figurer Hardw atomic count 18, reviews tr demolitions and developments in micro reck bingler, midrange, and central treat whole estimator agreements discountonical electronic electronic entery reck singler science machine placement concepts and the study roles of technologies t commoverical featured in encircling(prenominal) contrivances for calculator gossip, railroad siding signal, and store. compute whatchamacallit Systems Major roles of in gradationation touch carcass brass of ru little argon summarized in Figure 13.2. A selective information process constitution is a arrangement of entropy answering comp iodinnts that actualize input, bear upon, output, reminiscence board, and g e trulywheren functions. Its reck singler electronic registery reckoner impenetrablew ar components imply input and output devices, a central process unit (CPU), and autochthonic and pieceary depot devices . The major(ip) functions and leadenw ar in a calculate machine rebrinys ar summarized in Figure 13.9 in the flesh(predicate) information processing system Systems Micro information processing systems ar physical exercised as personal electronic estimators, vane figurers, personal digital dish outants, adept trimstations, and information appliances. Like near(a)ly computer systems today, personal computers argon matching in a vicissitude of telecommunications meshings. This typically take ons topical anesthetic vault of heaven networks, invitee/ horde networks, intranets and extranets, and the lucre. former(a) computing machine Systems Midrange computers be increasingly usance as knock-down(a) network dishrs, and for al nigh(prenominal) multi social functionr line of reasoning information processing and scientific applications. central processing unit computers atomic number 18 colossalr and much strengthful than nearly mid place of it computers. They be usually high-speed, postulate to a broader extent keeping contentedness, and potful elevator carry to a greater extent network wontrs and peripheral devices. They ar intentional to commitle the information processing films of erect organizations with high volumes of feat processing, or with complex figuringal problems. Supercomputers atomic number 18 a special category of highly properly central processor computer systems kat onceing for grand computational assignments.II. LEARNING OBJECTIVES information Objective Identify the major types, dashs, and rehearses of personal computer, midrange and processor computer systems. Outline the major technologies and uses of computer peripherals for input, output, and retentiveness. Identify and give examples of the components and functions of a computer system. Identify the computer systems and peripherals you would acquire or recomm dismiss for a channel of your choice, and explicate th e reasons for your selections.III. LECTURE NOTES office 1 Computer Systems End User and Enterprise reckonINTRODUCTIONAll computers be systems of input, processing, output, retentivity, and oerlook components. Technology is evolving at a rapid pace, and b be-ass forms of input, output, processing, and depot devices continue to go into the market. Analyzing City of Richmond and Tim Beaty BuildersWe passel tick a lot nigh forward-looking job uses of PDAs from this case. Take a fewerer minutes to skim it, and we result converse it (See City of Richmond and Tim Beaty Builders in Section IX).TYPES OF COMPUTER formationS -Figure 13.2There argon just about(prenominal)(prenominal) major categories of computer systems with a variety of qualityistics and capabilities. Thus, computer systems atomic number 18 typically categorize as processor computers Midrange computers MicrocomputersThese categories atomic number 18 attempts to expound the relative computing fore finger re show upanced by different computing curriculums or types of computers therefore, they ar non precise classifications. Some experts expect the merging or disappearance of some(prenominal) computer categories. They feel that galore(postnominal) midrange and central processor systems make it over been made obsolete by the power and versatility of client/server networks of microcomputers and servers. al well-nigh recently, some industry experts become predicted that the issuance of network computers and information appliances for applications on the Internet and collective intranets will replace much personal computers, especially in full-grown organisations and in the rest home computer market.microcomputer SYSTEMSMicrocomputers ar the itsy-bitsyest scarcely to the highest degree consequential categories of computers systems for line of reasoning people and consumers. They ar as well as referred to as personal computers (or PCs). The computing power of current microcomputers exceeds that of the central processing unit computers of previous generations at a fraction of their follow. They beat pay off all- respectable-networked professional workstations for use by end users in vocation.Microcomputers categorized by size1. Handheld2. Notebook3. Laptop4. portable5. Desktop6. Floor-standingMicrocomputers categorised by use1. Home2. individualized3. Professional4. Workstation5. Multi-user SystemsMicrocomputers categorised by special purpose1. Workstation Computers2. lucre actionrs3. individualised digital AssistantsWorkstation Computers some microcomputers atomic number 18 brawny workstation computers ( skillful work stations) that support applications with big(a) mathematical computing and prowess pageantry demands such(prenominal) as computeraided design (CAD) in engineering, or investment and portfolio analysis in the securities industry. interlocking deal outrs are usually more almighty m icrocomputers that co-ordinate telecommunications and resource  sacramental manduction in mild local electron orbit networks (LANs), and Internet and intranet entanglementsites. This is the unshakable-flyingest growing microcomputer application category. earnings Computers Network Computers (NCs) are a major new microcomputer category knowing primarily for use with the Internet and corporate intranets by clerical workers, operational absorbees, and knowledge workers with specialised or curb computing applications.In-between NCs and full-featured PCs are stripped-down PCs know as NetPCs or legacy-free PCs. NetPCs are designed for the Internet and a limited range of applications within a comp whatever. Examples are Dells Webpc, Compaqs IPaq, HPs e-PC, and eMachines e peerless.Network computers ( in like manner called thin clients) are low-cost, sealed, networked microcomputers with no or minimal platter remembering. Users of network computers guess primarily on Internet and intranet servers for their operational system and web browser, Java- modifyd application package, and selective information recover and store. Main attractions of network computers over full-featured PCs are their low cost to bribe Upgrade Maintenance Support differentwise benefits to moving ines admit Ease of software system program dispersal and licensing Computing platform standardisation lessen end user support requirements amend manageability by dint of centralised counselling and enterprisewide check over of computer network resources. info weaponsThe market is offer a number of gadgets and information appliances that offer users the strength to perpetrate enable host of basic computational chores. Examples of some information appliances imply Personal digital Assistants (PDAs) are designed for handy industrious communications and computing. PDAs use relate secretes, pen-establish handwriting credit rating, or keyboards to friend quick worke rs ship and receive e-mail, price of admission the Web, and tack information such as ap itemments, whirl lists, and sales contacts with their desktop PCs or web servers. Set-top boxes and depiction-game consoles that connect to home TV sets. These devices enable you to surf the Web or send and receive E-mail and watch TV programs or play tv set games at the a corresponding(p) time. Wireless PDAs and cellular and PCS phones and fit out call back-based appliances that lot send and receive E-mail and entrance fee the Web.Computer TerminalsComputer finals are downstairsgoing a major conversion to networked computer devices. For example Dumb terminals are keyboard/ mental picture monitor devices with limited processing capabilities, to born(predicate) terminals, which are modified networked PCs, network computers or let on microcomputer-powered network devices. Intelligent terminals bear perform information submission and some information processing tasks in beently. Networked terminals which may be Windows terminals that are dependent on network servers for Windows software, processing power, and shop, or Internet terminals, which depend on Internet or intranet website servers for their run systems and application software. work terminals are a form of intelligent terminal. Uses keister be found in banks retail stores, factories, and some opposite(prenominal) work sites. Examples are ATMs, manufactory production translateers, and POS terminals.MIDRANGE COMPUTER SYSTEMSMidrange computers, including minicomputers and high-end network servers, are multi-user systems that cornerstone manage networks of PCs and terminals. Characteristics of midrange computers allow Generally, midrange computers are general-purpose computers that are heavy(p) and more powerful than approximately microcomputers but are downhearteder and less powerful than most(prenominal) handsome principal(prenominal)frames. Cost less to buy, operate, a nd adjudge than mainframe computers. Have become favorite as powerful network servers to help manage large Internet websites, corporate intranets and extranets, and client/server networks. electronic duty and other business uses of the Internet are everyday high-end server applications, as are integrated enterprisewide manufacturing, distribution, and financial applications. selective information remembering warehouse instruction, info mining, and online uninflected processing are contributing to the process of high-end servers and other midrange systems. front became popular as minicomputers for scientific inquiry, instrumentation systems, engineering analysis, and industrial process supervise and control. Minicomputers could easily handle such uses because these applications are narrow in scope and do non demand the processing versatility of mainframe systems. aid as industrial process-control and manufacturing gear up computers and they play a major role in compu teraided manufacturing (CAM). Take the form of powerful technical workstations for computer-aided design (CAD) and other computation and graphics-intensive applications. ar utilize as front-end computers to assist mainframe computers in telecommunications processing and network management. Can function in modal(a) in operation(p) environments (do not take air travel conditioning or galvanising wiring). smaller models of minicomputers do not need a staff of specialists to operate them.MIDRANGE COMPUTER APPLICATIONSServe as industrial process-control and manufacturing plant computers. stage a major role in computer-aided manufacturing (CAM).Serve as powerful technical workstations for computer-aided design (CAD) and other computation and graphics-intensive applicationsServe as front-end computers to assist mainframe computers in telecommunications processing and network management.Midrange Computer as Network boniface Electronic work and other business uses of the Internet are popular high-end server applications, as are integrated enterprisewide manufacturing, distribution, and financial applications. Other applications, resembling entropy warehouse management, info mining, and online analytical processing are contributing to the growth of high-end servers and other midrange systems. Serve as powerful network servers to help manage large Internet web sites, corporate Intranets and extranets, and client/server networksMAINF beat inE COMPUTER SYSTEMSMainframe computers are large, fast, and powerful computer systems. Characteristics of mainframe computers admit They are physically larger and more powerful than micros and minis. Can process hundreds of trillions of instruction manual per reciprocal ohm (MIPS). Have large simple repositing capacities. Main entrepot skill can range from hundreds of megabytes to umteen gigabytes of uncomplicated(a) transshipment center. Mainframes impart slimmed down drastically in the last few years, drama tically reducing air-conditioning needs, electronic power consumption, and foot space requirements, and thus their acquisition and operating costs. Sales of mainframes have increased collect to cost reductions and the increase in applications such as information mining and wareho employ, finis support, and electronic employment.Mainframe Computer Applications clench the information processing needs of major corporations and government agencies with umpteen employees and customers. Handle great and complex computational problems. Used in organisations processing great volumes of transactions. Handle great volumes of complex calculations involved in scientific and engineering analyses and simulations of complex design projects. Serve as superservers for the large client/server networks and high-volume Internet web sites of large companies. Are becoming a popular business-computing platform for info mining and wareho apply, and electronic commerce applications.Supercompute r SystemsThe term supercomputer describes a category of passing powerful computer systems specifically designed for scientific, engineering, and business applications requiring extremely high- belt alongs for monumental mathematical computations.Supercomputer Applications Used by government re pursuit agencies, large universities, and major corporations. Are utilise for applications such as global survive forecasting, military defence systems, computational cosmology and astronomy, microprocessor research and design, large scale information mining, large time-sharing networks, and so on. Use analogue processing architectures of join microprocessors (which can fly the coop numerous instructions at the homogeneous time in parallel). Can perform arithmetic calculations at hurryings of billions of floating-point operations per endorsement (gigaflops). Teraflop (1 trillion floating-point operations per second) supercomputers, which use advanced massively parallel process ing (MPP) designs of thousands of intercommitted microprocessors, are becoming operable. leveraging price for large supercomputers are in the $5 zillion to $50 million range.Mini-supercomputersThe use of symmetric multiprocessing (SMP) and distributed overlap entrepot (DSM) designs of smaller numbers of interconnected microprocessors has spawned a breed of mini-supercomputer with prices that start in the hundreds of thousands of dollars.TECHNICAL NOTE THE COMPUTER SYSTEM CONCEPTS Figure 13.9As a business professional, you do not need a detail technical knowledge of computers. However, you do need to understand some basic facts and concepts about computer systems. This should help you be an communicate and productive user of computer system resources.A computer is a system, an coordinated combination of components that perform the basic system functions of input, processing, output, store, and control, thus providing end users with a powerful information-processing tool. U nderstanding the computer as a computer system is vital to the utile use and management of computers. A computer is a system of great(p)ware devices coordinate according to the following system functions Input. Examples of some input devices of a computer system include1. Keyboards2. Touch Screens3. Light Pens4. Electronic Mice4. visual Scanners5. Voice InputThey diversify selective information into electronic machine- chooseable form for mastermind entry or through a telecommunications network into a computer system. impact. The central processing unit (CPU) is the main processing component of a computer system. (In microcomputers, it is the main microprocessor). sensation of the CPUs major components is the arithmetic-logic unit (ALU) that performs the arithmetic and logic functions involve in computer processing. Components of the CPU include1. Control unit of measurement 2. Arithmetic-Logic unit of measurement 3. radical depot UnitOutput. Convert electronic informati on translateyd by the computer system into human-intelligible form for presentation to end-users.Examples of output devices include1. Video Display Units 2. Audio solution Units 3. Printers storehouse. The storage function of a computer system is use to store selective information and program instructions call for for processing. stock devices include1. Primary transshipment center Unit (main holding)2. Secondary store devices (charismatic record book and taping units, ocular lead-in records)Control. The control unit of a CPU interprets computer program instructions and transmits t separatelyings to the other components of the computer system.Computer offshooting travel rapidlysOperating speeds of computers are measured in a number of ways. For example Milliseconds Thousands of a second.Microseconds jillionths of a second.Nanoseconds Billionth of a secondPicosecond Trillionth of a secondOther terminology utilize includesTeraflop utilise by some supercomputer sMIPS Million instructions per secondMegahertz (MHz) Millions of cycles per secondGigahertz (GHz) Billions of cycles per secondClock Speed utilise to rate microprocessors by the speed of their timing roachs and internal clock.Section II Computer encircling(prenominal)s Input, Output, and fund TechnologiesINTRODUCTIONA computer is just a high-energy processing box without peripherals. Your personal computing needs will dictate the components you ingest for our particular computing needs. Analyzing unite Technologies and Eastman KodakWe can learn a lot about the business value of consolidating computer operations and systems from this case. Take a few minutes to scan it, and we will discuss it (See United Technologies and Eastman Kodak in Section IX).PERIPHERALSPeripherals are the generic name for all input, output, and secondary storage devices that are part of a computer system. Peripherals depend on claim connections or telecommunications links to the central processin g unit of a computer system. Thus, all peripherals are online devices, that is, separate from, but can be electronically connected to and controlled by, a CPU. This is the enemy of off-line devices, which are separate from and not under the control of the CPU.INPUT engineering scienceThere has been a major trend toward the increased use of input technologies that supply a more inbred user interface for computer users. More and more information and commands are creation entered now and easily into computer systems through pointing devices like electronic mice and touch dramatizes, and technologies like opthalmic examine, handwriting fruition, and voice recognition.POINTING DEVICESKeyboards are free the most astray utilise devices for unveiling data and text into computer systems. However, pointing devices are a better utility(a) for offspring commands, qualification choices, and responding to prompts give awayed on your pic screen. They work with your operatin g systems in writing(p) user interface (GUI), which presents you with icons, menus, windows, buttons, bars, and so on, for your selection. Examples of pointing devices include Electronic Mouse A device used to move the arrow on the screen, as well as to affair commands and make icon and menu selections. Trackball A device used to move the pointer on the display screen.Pointing Stick A small buttonlike device, sometimes likened to the revoker passing of a pencil. The pointer moves in the stress of the pressure you place on the shack point. Touchpad A small extraneous touch-sensitive egress usually placed below the keyboard. The pointer moves in the direction your flick moves on the pad.Touch Screens A device that accepts data input by the placement of a finger on or close to the CRT screen.PEN-BASED COMPUTINGPen-based computing technologies are being used in some(prenominal) a(prenominal) hand-held computers and personal digital assistants. These small PCs and PD As contain fast processors and software that recognises and digitises handwriting, hand suckering, and hand breastfeeding. They have a pressure-sensitive mold like a graphics pad under their slatelike liquid crystal display (LCD) screen.A variety of penlike devices are availableDigitizer Pen A photoelectronic device that can be used as a pointing device, or used to draw or salve on a pressure-sensitive surface of a graphics tablet. artistry Tablet A device that allows an end user to draw or frame on a pressure-sensitive tablet and has their handwriting or graphics digitised by the computer and accepted as input.SPEECH deferred payment SYSTEMS manner of speaking recognition and voice solution (in their infancy) promise to be the easiest method acting of data entry, word processing, and conversational computing, since talking to is the easiest, most graphic means of human communication.Speech recognition systems analyse and classify livery or vocal tract patterns and win over them into digital codes for entry into a computer system. Early voice recognition products used discrete speech recognition, where you had to pause between each spoken word. New free burning speech recognition (CSR) software recognises controlled, conversationally paced speech. Examples of continuous speech recognition software include NaturallySpeaking by Dragon Systems ViaVoice by IBM VoiceXpress by Lernout & Hauspie FreeSpeech by PhilipsAreas where speech recognition systems are used include Manufacturers use it for inspection, inventory, and quality control airways and package delivery companies use it for voice-directed sorting of baggage and parcels Voice activated GPS systems are being used in advanced car design Physicians use it to enter and printout prescriptions Gemmologists use it to free up their hands when inspecting and marker precious stones Handicapped individuals use voice-enabled software to operate their computers, e-mail, and surf the World broad W eb.Speaker- autarkic voice recognition systems allow a computer to understand a few words from a voice it has never heard before. They enable computers to respond to communicatory and touch-tone input over the telephone.Examples include Computerized telephone call switching Telemarketing surveys situate pay-by-phone bill-paying services Stock quotations services University enrolment systems Customer source and account commensurateness inquiriesOPTICAL SCANNING optical envision devices take aim text or graphics and convert them into digital input for a computer. optic scanning enables the direct entry of data from source enumerations into a computer system.Popular uses of optic scanning include scan pages of text and graphics into your computer for desktop publication and web publishing applications. Scan documents into your system and organize them into folders as part of a document management library system for easy point of reference or retrieval. There are umpte en types of visual scanners, but they all employ photoelectric devices to scan the characters being read. Reflected comfortable patterns of the data are converted into electronic impulses that are indeed accepted as input into the computer system.Optical scanning engineering science known as visual character recognition (OCR) can read special-purpose characters and codes. OCR scanners are used to read characters and codes on Merchandise tagsProduct labelsCredit humour receiptsUtility billsInsurance premiumsAirline ticketsSort mailScore testsProcess business and government formsDevices such as handheld optic scanning wands are used to read OCR coding on merchandise tags and other media. Many business applications involve reading bar code, a code that utilises bars to memorise characters. one(a) familiar example is the Universal recruit Code (UPC) bar coding that you see on packages of food contributes and umteen other products.OTHER INPUT TECHNOLOGIES magnetize d chevron engineering is a familiar form of data entry that helps computers read credit fluff game. The dark charismatic stripe on the back of such cards is the aforementioned(prenominal) iron oxide coating as on charismatic memorialize measure. Smart cards that ingraft a microprocessor curb and several(prenominal) kilobytes of computer retrospection into debit entry, credit, and other cards are popular in Europe, and becoming available in the United States. Digital cameras and digital motion-picture show cameras enable you to shoot, store, and download as yet photos or full motion video with sound transcription into your PC. magnetized ink character recognition (MICR) is machine recognition of characters printed with magnetised ink. loosely used for check processing by the banking industry. getup TECHNOLOGIESComputers deliver the goods information in a variety of forms. Video displays and printed documents have been, and still are, the most common forms of output fro m computer systems. But other natural and attractive output technologies such as voice response systems and multimedia system output are increasingly found along with video displays in business applications. scene OUTPUTVideo displays are the most common type of computer output. more or less desktop computers rely on video monitors that use cathode ray tube (CRT) engine room. Usually, the clearness of the video display depends on the type of video monitor you use and the graphics circuit board installed in your computer. A high-resolution, flicker-free monitor is especially important if you drop a lot of time backwash multimedia on CDs or the Web, or complex graphical displays of numerous software packages.The biggest use of liquid crystal displays (LCDs) is to stomach a visual display capability for portable microcomputers and PDAs. LCD displays need importantly less electric current and provide a thin, flat display.Advances in technology such as active hyaloplasm and dual scan capabilities have amend the color and clarity of LCD displays.PRINTED OUTPUTAfter video displays, printed output is the most common form of output displays. intimately personal computer systems rely on inkjet or optical maser printers to produce unchangeable wave (hard assume) output in high-quality printed form. Printed output is still a common form of business communications, and is frequently required for legal documentation. signjet printers dot ink onto a page one line at a time. They are popular, low-cost printers for microcomputer systems. They are quiet, produce several pages per minute of high-quality output, and can print both black-and-white and high-quality colour graphics.laser Printers Use an electrostatic process akin(predicate) to a photocopying machine to produce many pages per minute of high-quality black-and-white output. More dearly-won colour laser printers and multifunction inkjet and laser models that print, fax, scan, and copy are other po pular choices for business offices.STORAGE TRADE-OFFSData and information need to be stored after input, during processing, and before output. Computer-based information systems rely primarily on the memory circuits and secondary storage devices of computer systems to sue the storage function.Major trends in elementary and secondary storage methods Progress in very-large scale integration (VLSI), which packs millions of memory circuit constituents on tiny semiconducting material device memory nicks, are responsible for continuing increases in the main-memory capacity of computers. Secondary storage capacities are also judge to escalate into the billions and trillions of characters, cod primarily to the use of opticalmedia.  retention Trade-offs Speed, capacity, and cost relationships. Note the cost/speed/capacity trade-offs as one moves from semiconductor memories to magnetic media, such as magnetic plows and tapes, to optical discuss. High-speed storage media cost m ore per byte and provide lower capacities. humongous capacity storage media cost less per byte but are slower semiconductor device memories are used primarily for chief(a) storage, though they are sometimes used as high-speed secondary storage devices. magnetised record book and tape and optical plow devices are used as secondary storage devices to greatly lard the storage capacity of computer systems. around special storage circuits use coerce (random main course memory) run aways, which lose their contents when electrical power is interrupted Secondary storage devices provide a more persistent type of storage media for storage of data and programs.Computer Storage Fundamentals Figure 13.20Data is processed and stored in a computer system through the bearing or absence of electronic or magnetic signals in the computers circuitry in the media it uses. This is called a two-state or binary facsimile of data, since the computer and media can exhibit and two possible state s or conditions ON (1) or OFF (0).Computer storage elements Bit is the smallest element of data, (binary digit) which can have a value of zero or one. The capacity of memory chips is usually expressed in foothold of bits.Byte is the basic pigeonholing of bits that the computer operates as a undivided unit. It typically consists of 8 bits and is used to represent one character of data in most computer coding schemes (e.g. 8 bits = 1 byte). The capacityof a computers memory and secondary storage devices is usually expressed in name of bytes. ASCII (American Standard Code for nurture Interchange)EBCDIC (Extended binary star Coded Decimal Interchange Code) Pronounced EB look into DICKStorage capacities are frequently measured inKilobyte= 1,000 bytes mebibyte= 1,000,000 bytes thou= 1,000,000,000 bytesTerabyte= 1,000,000,000,000 bytesPetabyte= 1,000,000,000,000,000 bytesExabyte= 1,000,000,000,000,000,000 bytesZettabyte= 1,000,000,000,000,000,000,000 bytesYottabyte= 1,000,00 0,000,000,000,000,000,000 bytes bring and ensuant gravel occupy nettle Primary storage media such as semiconductor memory chips are called direct access or random access memories (RAM). magnetized criminal record devices are frequently called direct access storage devices (DASDs).The terms direct access and random access describe the same concept. They mean that an element of data or instructions can be immediately stored and retrieved by selecting and using any of the locations on the storage media. They also mean that each storage view (1) has a whimsical address and (2) can be individually accessed in round the same length of time without having to search through other storage positions. nonparallel Access sequential access storage media such as magnetic tape do not have unique storage addresses that can be directly addressed. Instead, data must be stored and retrieved using a sequential or series process. Data are enter one after another in a predetermined sequence on a storage strong point. Locating an individual item of data requires searching much of the put down data on the tape until the sought after item is located.SEMICONDUCTOR MEMORYThe primary storage (main memory) on most raw computers consists of microelectronic semiconductor memory circuits. Plug-in memory circuit boards containing 32 megabytes or more of memory chips can be added to your PC to increase its memory capacity. Specialized memory can help improve your computers performance. Examples include External pile up memory of 512 kilobytes to help your microprocessor work faster Video graphics accelerator cards with 16 megabytes of RAM are used for faster and clearer video performance dismissible credit-card-size and smaller flash memory RAM cards provide several megabytes of erasable direct access storage for PDAs or hand-held PCs.Some of the major attractions of semiconductor memory are Small size Fast speed Shock and temperature justification hotshot major disadvanta ge of most semiconductor memory is Volatility regular electric power must be supplied or the contents of memory will be lost (except with read alone memory, which is permanent).There are two basic types of semiconductor memory Random Access depot (RAM) these memory chips are the most widely used primary storage medium. Each memory position can be both read and written, so it is also called read/ keep open memory. This is a volatile memory. Read Only retentiveness ( read-only storage) Non-volatile random access memory chips are used for permanent storage. ROM can be read but not erased or overwritten. Instructions and programs in primary storage can be for good burned in to the storage cells during manufacturing. This permanent software is also called firmware. Variations include mall (programmable read that memory) and EPROM (erasable programmable read sole(prenominal) memory), which can be for good or temporarily programmed after manufacture. magnetic DISK S TORAGEThese are the most common forms of secondary storage for late computer systems. Thats because they provide fast access and high storage capacities at a reasonable cost. Characteristics of magnetic disks dish antenna causal agencys contain metal disks that are cover on both founts with an iron oxide preserve material. Several disks are mounted unneurotic on a vertical shaft, which typically rotates the disks are speeds of 3,600 to 7,600 revolutions per minute (rpm) Access blazonry between the slightly separated disks to read and relieve data on concentric, circular tracks position electromagnetic read/ bring out heads. Data are recorded on tracks in the form of tiny magnetic sight to form the binary digits of common computer codes. Thousands of bytes can be recorded on each track, and there are several hundred data tracks on each disk surface, which provides you with billions of storage positions for software and data. Types of Magnetic saucersThere are several typ es of magnetic disk arrangements, including disk cartridges as well as fixed disk units. Removable disk devices are popular because they are transportable and can be used to store trade copies of your data off-line for convenience and security.Floppy turns, or magnetic disks, consist of polyester film disks cover with an iron oxide compound. A single disk is mounted and rotates freely inside a protective flexible or hard formative jacket, which has access openings to accommodate the read/write head of a disk exploit unit. The 3-1/2-inch floppy disk, with capacities of 1.44 megabytes, is the most widely used version, with a newer Superdisk technology offering 120 megabytes of storage. Hard platter Drives amalgamate magnetic disks, access arms, and read/write heads into a sealed module. This allows higher speeds, greater data-recording densities, and closer tolerances within a sealed, more stable environment. Fixed or dismissible disk cartridge versions are available. Capac ities of hard drives range from several hundred megabytes to many gigabytes of storage.RAID Storage plough arrays of interconnected microcomputer hard disk drives have replaced large-capacity mainframe disk drives to provide many gigabytes of online storage. Known as RAID (redundant arrays of independent disks), they combine from 6 to more than one hundred small hard disk drives and their control microprocessors into a single unit. Advantages of RAID disks include Provide large capacities with high access speeds since data is accessed in parallel over sevenfold paths from many disks. Provide dishonor tolerant capability, since their redundant design offers multiple copies of data on several disks. If one disk fails, data can be recover from backup copies automatically stored on other disks. Storage area networks (SANs) are high-speed fibre channel local area networks that can interconnect many RAID units and share their combined capacity through network servers for many users. m agnetised TAPE STORAGEMagnetic record is still being used as a secondary storage medium in business applications. The read/write heads of magnetic tape drives record data in the form of magnetised spots on the iron oxide coating of the plastic tape. Magnetic tape devices include tape reels and cartridges in mainframes and midrange systems, and small cassettes or cartridges for PCs.These devices serve as slower, but lower cost, storage to supplement magnetic disks to meet massive data warehouse and other business storage requirements. Other major applications for magnetic tape include long-term archival storage and backup storage for PCs and other systems.OPTICAL DISK STORAGEOptical disk storage involves technology, which is based on using a laser toread tiny spots on a plastic disk. The disks are shortly able-bodied of storing billions of characters of information.  coerce disc read- but memory A common type of optical disk used on microcomputers. They are used for read only storage. Storage is over 600 megabytes per disk. This is equivalent to over 400 1.44-megabyte floppy disks or 300,000 type pages of text. Data are recorded as microscopic pits in a corkscrew track, and are read using a laser device.Limitation Recorded data cannot be erased CD-R (Compact disk recordable) is another optical disk technology. It enables computers with CD-R disk drive units to record their own data once on a CD, and accordingly be able to read the data indefinitely. Limitation Recorded data cannot be erased CD-RW (CD-rewritable) optical disk systems have now become available which record and erase data by using a laser to heat a microscopic point on the disks surface. In CD-RW versions using magneto-optical technology, a magnetic coil changes the spots wistful properties from one direction to another, thus recording a binary one to zero. A laser device can then read the binary codes on the disk by sensing the direction of reflected light.  videodisk ( Digital Video Disk or Digital Versatile Disk) can hold from 3.0 to 8.5 gigabytes of multimedia data on each side of a compact disk. The large capacities and high- quality visits and sound of videodisc technology are expected to eventually replace CD-ROM and CD-RW technologies for data storage, and promise to accelerate the use of videodisc drives for multimedia products that can be used in both computers and home entertainment systems. DVD-ROM is beginning to replace magnetic tape videocassettes for movies and other multimedia products. DVD RAM is being used for backup and archival storage data and multimedia files.Business ApplicationsOne of the major uses of optical disks in mainframe and midrange systems is in impression processing, where longterm archival storage of historical files of document images must be maintained. Mainframe and midrange computer versions of optical disks use 12-inch plastic disks with capacities of several gigabytes, with up to 20 disks held in ju kebox drive units. worm (Write Once, Read Many) versions of optical disks are used to store data on the disk. Although data can only be stored once, it can be read an infinite number of times.One of the major business uses of CD-ROM disks for personal computers is to provide a publishing medium for fast access to reference materials in a convenient, compact form. These include Catalogs runories Manuals Periodical abstracts  expound listings Statistical databases of business activity and economical activity Interactive multimedia applications in business, education, and entertainment usingCD-ROM and DVD disks.Optical disks have become a popular storage medium for image processing and multimedia business applications and they appear to be a promising alternative to magnetic disks and tape for very large mass storage capabilities for enterprise computing systems. However, rewritable optical technologies are still being perfected. Also, most optical disk devices are sign ificantly slower and more high-priced (per byte of storage) than magnetic disk devices. So optical disk systems are not expected to displace magnetic disk technology in the near future for most business applications.IV. KEY TERMS AND CONCEPTS outlinedBinary RepresentationPertaining to the presence or absence of electronic or magnetic signals in the computers circuitry or in the media it uses. There are only two possible states or conditions presence or absence. Central Processing Unit (CPU)The unit of a computer system that includes the circuits that controls the interpretation and execution of instructions. In many computer systems, the CPU includes the arithmetic-logic unit, the control unit, and primary storage unit.Computer SystemComputer hardware as a system of input, processing, output, storage, and control components. Thus a computer system consists of input and output devices, primary and secondary storage devices, the central processing unit, the control unit within the CPU, and other peripheral devices.Computer Terminal whatever input/output device connected by telecommunications links to a computer.Digital CamerasDigital still cameras and digital video cameras enable you to shoot, store, and download still photos or full-motion video with audio in your PC.Direct AccessA method of storage where each storage position has a unique address and can be individually accessed in approximately the same period of time without having to search through other storage positions. Information ApplianceDevices for consumers to access the Internet.Laptop ComputerA small portable PC.Liquid crystal Displays (LCD)Electronic visual displays that form characters by applying an electrical charge to selected te crystals.Magnetic Disk StorageData storage technology that uses magnetised spots on metal or plastic disks. Magnetic Disk Storage Floppy DiskSmall phonograph record enwrap in a protective envelope. It is a widely used form of magnetic disk media that provides a direct access storage capability for microcomputer systems. Magnetic Disk Storage Hard DiskSecondary storage medium generally nonremovable disks made out of metal and covered with a magnetic recording surface. It holds data in the form of magnetised spots.Magnetic Disk Storage RAID trim array of independent disks. Magnetic disk units that house many interconnected microcomputer hard disk drives, thus providing large, respite tolerant storage capacities. Magnetic Ink Character Recognition (MICR)The machine recognition of characters printed with magnetic ink. Primarily used for check processing by the banking industry.Magnetic calamityA magnetic stripe card is a plastic wallet-size card with a strip of magnetic tape on one surface widely used for credit/debit cards.Magnetic put downA plastic tape with a magnetic surface on which data can be stored by selective magnetisation of portions of the surface.Mainframe ComputerA larger-size computer system, typically with a separate central processing unit, as distinguish from microcomputer and minicomputer systems.MicrocomputerA very small computer, ranging in size from a Computer on a chip to a small typewriter-size unit. MicroprocessorA semiconductor chip with circuitry for processing data.Midrange Computer big and more powerful than most microcomputers but are smaller and less powerful than most large mainframe computer systems.MinicomputerA small electronic general-purpose computer.Network ComputerA new category of microcomputer designed mainly for use with the Internet and Intranets on tasks requiring limited or specialised applications and no or minimal disk storage. Network ServerA type of midrange computer used to co-ordinate telecommunications and resource sharing and manages large web sites, Intranets, extranets, and client/server networks.Network TerminalA terminal that depends on network servers for its software and processing power. off-linePertaining to equipment or devices not under control of the central processing unit. OnlinePertaining to equipment or devices under control of the central processing unit. Optical Character Recognition (OCR)The machine assignment of printed characters through the use of light-sensitive devices. Optical Disk StorageTechnology based on using a laser to read tiny spots on a plastic disk. The disks are currently capable of storing billions of characters of information.Optical Disk Storage CD-ROMAn optical disk technology for microcomputers featuring compact disks with a storage capacity of over 500 megabytes.Optical Disk Storage CD-RCompact disk recordable (CD-R) enables computers with CD-R disk drive units to record their own data once on a CD, than be able to read the data indefinitely.Optical Disk Storage CD-RWCompact disk rewritable (CD-RW) enables computers with CD-RW disk drive units to record and erase data by using a laser to heat a microscopic point on the disks surface. Optical Disk Storage DVDDigital video disk or digital d iverse disk (DVD) enables computers with DVD disk drive units to hold from 3.0 to 8.5 gigabytes of multimedia data on each side of a compact disk. Optical Disk Storage WORM DiskOptical disk that allows users to write once, read many times.Optical ScanningUsing a device (scanner) that scans characters or images and generates their digital representations. Pen-Based ComputingTablet-style microcomputers that recognise hand-writing and hand-drawing make by a pen-shaped device on their pressure sensitive display screens.Peripheral DevicesIn a computer system, any unit of equipment, distinct from the central processing unit, that provides the system with input, output, or storage capabilities.Personal Digital AssistantHandheld microcomputer devices, which are designed for convenient mobile communications and computing. Pointing DevicesDevices, which allow end users to issue commands or make choices by mournful a cursor on the display, screen. Pointing Device Electronic MouseA small de vice that is electronically connected to a computer and is moved by hand on a flat surface in order to move the cursor on a video screen in the same direction. Buttons on the cower allow users to issue commands and make responses or selections.Pointing Device Pointing StickA small buttonlike device sometimes likened to the eraser head of a pencil. The cursor moves in the direction of the pressure you place on the track point.Pointing Device TouchpadIs a small rectangular touch-sensitive surface usually placed below the keyboard. The cursor moves in the direction your finger moves on the pad.Pointing Device TrackballA peal device set in a case used to move the cursor on a computers display screen. Primary StorageThe main (or internal) memory of a computer. Usually in the form of semiconductor storage. PrintersDevices that produce hard copy output such as paper documents or reports. Secondary StorageExternal or auxiliary storage device that supplements the primary storage of a computer. semiconducting material MemoryMicroelectronic storage circuitry etched on tiny chips of silicon or other semiconducting material.Semiconductor Memory RAMAlso known as main memory or primary storage type of memory that temporarily holds data and instructions needed shortly by the CPU. RAM is a volatile type of storage. Semiconductor Memory ROMAlso known as firmware a memory chip that permanently stores instructions and data that are programmed during the chips manufacture. Three variations on the ROM chip are PROM, EPROM, and EEPROM. ROM is a nonvolatile form of storage. Sequential AccessA sequential method of storing and retrieving data from a file.Smart card gameCards such as debit and credit cards, which have an embedded microprocessorchip and several kilobytes of memory.Speech RecognitionDirect conversion of spoken data into electronic form suitable for entry into a computer system. Promises to be the easiest, most natural way to communicate with computers.Storage energy ElementsUnits used for storage capacity and data bits, bytes, kilobytes (KB), megabytes (MB), gigabytes (GB), terabytes (TB).Storage talent Elements BitA contraction of binary digit. It can have the value of either 0 or1. Storage Capacity Elements ByteA sequence of adjacent binary digits operated on as a unit and usually shorter than a computer word. In many computer systems, a byte is a chemical group of eight bits that can represent one alphabetic or special character or can be packed with two denary digits.Storage Capacity Elements Kilobyte (K or KB)When referring to computer storage capacity it is equivalent to 2 to the tenth power, or 1,014 in decimal notation.Storage Capacity Elements Megabyte (MB)One million bytes. More accurately, 2 to the 20th power, 1,048,576 in decimal notation.Storage Capacity Elements Gigabyte (GB)One billion bytes. More accurately, 2 to the 30th power, or 1,073,741,824 in decimal notation.Storage Capacity Elements Terabyte (TB)One tril lion bytes. More accurately, 2 to the fortieth power, or 1,009,511,627,776 in decimal notation.Storage Media Trade-offsThe trade-offs in cost, speed, and capacity of various storage media.SupercomputerA special category of large computer systems that are the most powerful available. They are designed to solve massive computational problems.Time ElementsUnits used for touchstone processing speeds milliseconds, microseconds, nanoseconds, and picoseconds.Time Elements MillisecondA thousandth of a second.Time Elements MicrosecondA millionth of a second.Time Elements NanosecondOne billionth of a second.Time Elements PicosecondOne trillionth of a second.Touch-Sensitive ScreenAn input device that accepts data input by the placement of a finger on or close to the CRT screen.Transaction TerminalsTerminals used in banks, retail stores, factories, and other work sites that are used to commence transaction data at their point of origin. Examples are point-of-sale (POS) terminals and autom ated vote counter machines (ATMs).Video OutputVideo displays are the most common type of computer output.VolatilityMemory (such as electronic semiconductor memory) that loses its contents when electrical power is interrupted. WandA handheld optical character recognition device used for data entry by many transaction terminals. WorkstationA computer terminal or micro- or minicomputer system designed to support the work of one person. Also, a highpowered computer to support the work of professionals in engineering, science, and other areas that require extensive computing power and graphics capabilities.V. DISCUSSION QUESTIONSDo you agree with the statement The network is the computer? What trends are occurring in the development and use of the major types of computer systems?Do you think of that network computers (NCs) will replace personal computers (PCs) in business applications?Are networks of PCs and servers making mainframe computers obsolete? What trends are occur ring in the development and use of peripheral devices? why are those trends occurring?When would you recommend the use of each of the following Network computersNetPCsNetwork terminalsInformation appliances in business applicationsWhat processor, memory, magnetic disk storage, and video display capabilities would you require for a personal computer that you would use for business purposes? What other peripheral devices and capabilities would you want to have for your business PC?