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1 Chapter 1 Introduction to Computers and Information Processing.

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1 1 Chapter 1 Introduction to Computers and Information Processing

2 2 Types of Computer

3 3 Objectives 1.Describe at least two major differences between analog and digital computer. Give examples of analog and digital devices. 2.Differentiate between dedicated, special purpose, and general-purpose computers.

4 4 Major Families Computers DigitalAnalog General Purpose Dedicated Special Purpose  Different types of computer are shown in Figure 1.1. Figure 1.1 Types of Computer

5 5 Major Families (continued) n The major differences between digital and analog computers are summarized in Table 1.1. DataDigital ComputerAnalog Computer Represented byDigits 0 and 1Electrical voltages Calculated byCounting digitsCombining and measuring voltages Controlled byStored programsConnections on patch-panel PrecisionGreaterLimited Quantity of data storage LargeSmall Table 1.1 Major Differences Between Digital and Analog Computers

6 6 Computer for Application n Dedicated, special-purpose, and general-purpose computers are different in relative efficiency, speed, cost, and economy of operation, and versatility. n Figure 1.2 shows the relationships between dedicated, special-purpose, and general-purpose computers.

7 7 Computer for Application (continued) Higher Lower Dedicated Computer Efficiency, Speed, and Special-Purpose Economy Computer Versatility General-Purpose Computer Lower Higher Figure 1.2 Differences Between Dedicated, Special-Purpose, and General-Purpose Computers

8 8 The Computer Revolution

9 9 The Computer As a Productivity Tool n Much of the work done today is done by computers. n Computers have automated many difficult, dangerous, and even humanly impossible tasks. n Automation - when mechanical or electronic devices take the place of human observation or effort.

10 10 The Computer As a Productivity Tool (continued) n Computers are able to handle the “detail” and leave important things to the human. n Computers make it possible to solve difficult problems. n When used effectively, computers can increase productivity at home and at the office.

11 11 The Information Revolution

12 12 Objectives 1.Differentiate between data and information. 2.Identify the sources of information.

13 13 Data, Knowledge, and Information nThe information revolution is the result of various societal and economic changes brought about by rapid increases in the amount of available:  data  knowledge  information

14 14 Data n Data - (the plural of datum) are raw facts that convey little meaning by themselves. n Data – raw, unorganized facts that describe reality. n All facts can be considered to be data, including such descriptions of reality as sounds and images.  determining their relevance  converting them into information Data

15 15 Knowledge n Knowledge - the body of rules, guidelines, and procedures used to select, organize, and manipulate data to make it more useful for a specific task. Knowledge

16 16 Selection, Organization, and Manipulation n Selecting or rejecting facts based on their relevancy to a particular task is part of the process of converting data into information. n Even facts not suited to a particular purpose are data. Selection Organization Manipulation Selection Organization Manipulation

17 17 Information n Information - data that has been selected, organized, and manipulated, and is appropriate for a particular purpose. n Information is data that has been made more useful through the application of knowledge. n For example, your first test grade of, say, 93 is information to you but is probably regarded only as data by your teacher. Information

18 18 Sources of Information n Information can be of two general types: quantitative or qualitative. n Quantitative information tells how much or how many and can be presented in two forms, as numerical or graphical information.  For example, there are 12 roses in the vase.  Quantitative information is used throughout businesses. How many units were sold? Or How many units were sold? Or How many pounds are being spent on employee salaries? How many pounds are being spent on employee salaries?

19 19 Sources of Information n Qualitative information describes something in nonquantitative terms.  For example, the roses in the vase are red.  Qualitative characteristics can be used to describe job categories or positions, such as marketing manager, graphics designer, or programmer.

20 20 Sources of Information (continued) nThe two basic sources of information are  internal, those gathered within an organization, and  external, those gathered outside the organization. n Three common internal sources are  Documents (balance sheet, employee file, …),  Observations (observing a situation or event), and  Surveys (form of questionnaires, telephone interviews, or personal interviews). n Common external sources include surveys, annual reports from other organizations, statistics from government agencies, trade publications, and research reports.

21 21 Information Processing

22 22 Information Processing n Information processing - the act of using a computer to assist in the conversion or processing of data into meaningful information. n The computer performs four basic functions:  input  processing  output  storage

23 23 Information Processing

24 24 Input Input Programs Data n Data - facts entered into the computer. n Programs - specific processing instructions.

25 25 Processing Processing Programs Data and Information for current and future use Programs Data Information n Processing - the computer selects, organizes, and manipulates the data according to the program instructions.

26 26 Output n Information - the converted data that is either made immediately available for use or placed in storage for future use. Output Information

27 27 Storage n Storage - an important function that enables the processing activity to be accomplished more efficiently by providing a place to hold data, programs, and even output until they are needed. Storage Programs Data and information for current and future use

28 28 What are Computers and Information System

29 29 Objectives 1.Define the terms computer and information system. 2.Recognize the importance of processing a basic level of knowledge, understanding, and skill in using computers and information systems. 3.State the purpose of a computer, describe the three basic functions that computers perform, and explain the advantage of using a computer to accomplish them.

30 30 What are Computers n A computer is an electronic device that can accept input, process it in a prescribed manner, output the results, and store the results for later use. n A computer is a tool used to process data into information.

31 31 What are Computers (continued) n Microelectronics - the miniaturization of the components of an electronic circuit. n Electronic circuit - a series of components that forms a pathway capable of carrying an electrical current. n Integrated circuit - an electronic circuit placed together with a single piece of semiconducting material (silicon). n Microprocessor - a special type of integrated circuit.  consists of thousands of electrical circuits etched into a very small slice of silicon  accepts and processes inputs, and delivers outputs

32 32 What are Information System n A system is any set of components that work together to perform a task. n An information system is a set of components that work together to manage the acquisition, storage, manipulation, and distribution of information.

33 33 Components of an Information Processing System n An information processing system components consists of:  hardware  software  data  people  procedures n All of these elements are organized for a specific purpose.

34 34 Hardware n Hardware includes all the physical equipment that make up a computer. n Hardware - those electronic components of an information system that you can see and touch. n Also includes telecommunications devices that allow input, processing, and output.

35 35 Software n Software is the instructions that cause the hardware to do the work. n Software - all the instructions that direct the operation of the computer system. n Includes both the programs and the written documentation explaining how to use the programs.

36 36 Data n Data provide the basis for the information generated by an information system. n Data - first input into the information processing system, processed, and then output as useful information. n It is important to recognize two important characteristics of data:  it is reusable  if it has been processed into information, that information can be considered as data and reprocessed into new information as necessary

37 37 People n The single most important component in an information processing system is people. People make products, deliver services, solve problems, and make decisions. n A person who uses computer hardware and software to perform a task is often referred to as an end user or user.

38 38 Procedures n The methods, policies, and rules that govern the use of the information processing system are called procedures. n Procedures are the instructions that tell a user how to operate and use an information system. n Some procedures might describe when to run a program, while others might describe when an end user can use the system, or how the removal of outdated data from storage should be handled.

39 39 Function of Information System nInformation systems are designed to perform three basic functions: 1.to accept data (input), 2.to convert data to information (process), and 3.to produce and communicate information in a timely fashion to users for decision making (output). n For example, many banks and other financial institutions use information systems to help determine whether a customer applying for a loan is a good risk (Table 1.2).

40 40 Function of Information System (continued) InputProcessOutput Data Customer specifies  Lending policy  Interest rate Data to Information Algorithms to convert data into desired information (e.g., customer credit worthiness, recommendation of whether to grant loan or not) Information Transformed into a form usable by loan officer (e.g., screen display, paper copy) Table 1.2 Functions of an Information System in Determining Customer Credit

41 41 Why Learn About Computers and Information Systems? nThe shift to a society that emphasizes the possession and dissemination of information has brought about an increasing use and reliance on computers and information systems in many professions. nTo complete in the marketplace you should posses a basic level of knowledge and understanding of computers and have the ability to effectively use them and the information they generate. nPossessing knowledge and understanding of computers and information systems in combination with the ability to use them effectively is called computer literacy.

42 42 Why Learn About Computers and Information Systems? (continued) nJudging the value of information and using the information generated wisely is called information literacy. nThere are many levels of ability. These range from  users who only need to know how to turn the computer on and off and use the software required by their job.  to those who must decide what data should be generated and how that data should be processed;  to those who repair, install, or design computers.

43 43 Why use a Computer? nThe purpose of a computer is to transform data into information. nComputers perform three basic functions: 1. performing arithmetic operations on numeric data, 2. testing relationships between data items by logically comparing values, and 3. storing and retrieving data.

44 44 Why use a Computer? (continued) nThe advantage of using computers for these functions over humans is that they can use perform them 1.faster 2.more accurate, and 3.more reliable.

45 45 Major System Units

46 46 Objectives 1.Sketch a simple block diagram of a computer system and label the five major units. These are the input, central processor, main memory, auxiliary storage, and output units. 2.Understand the purpose of software and describe the two main types. 3.Describe the steps involved in transforming data into information. 4.Understand the limitations of computers.

47 47 What Hardware Makes Up a Computer? n Computer hardware includes the system unit (Central Processing Unit and main memory), input devices, output devices, and secondary storage devices (Figure 1.3).

48 48 What Hardware Makes Up a Computer? (continued) Secondary Storage Arithmetic and Logic Unit Control Unit Memory Unit Input UnitOutput Unit Figure 1.3 Block Diagram of Basic Computer Units Control Data

49 49 Components of a Computer System n Computer System - a collection of the four basic components organized for some purpose. n The four basic components are:  input devices  processor unit  output devices  storage devices

50 50 Components of a Computer System

51 51 Four Basic Components of a Computer System n Input devices - transmit data to the processor unit for processing. n Processor unit - the “brains” of a computer system; contained within the system unit.  System unit - the “box” or case that contains the power supply, cooling fans, wires, and other devices.

52 52 Four Basic Components of a Computer System (continued) n Output devices - make the converted data (information) available for use. n Storage devices - hold data and programs for current and future use.  Primary storage - main memory.  Secondary storage - disk and tape.  Tertiary storage - disk and tape.

53 53 Four Basic Components of a Computer System (continued) Input Unit n Input refers to the data and instructions entered into a computer for processing or to the act of entering data, which is often called data entry. n An input device is the hardware that allows instructions and data to be entered into the computer for processing. n The input is converted into a digital form the computer can use. n It is important that data being input into the computer be accurate because they are the basis for producing the output generated.

54 54 Four Basic Components of a Computer System (continued) n There are numerous devices used for input. They are 1. Keyboard 2. Pointing devices 3. Touch screen – detect where a computer screen is touched and use this information to initiate an action. 4. Speech recognition (Voice recognition) – The ability of a computer to accept input by understanding the speech of a user.

55 55 Four Basic Components of a Computer System (continued) 5. Optical recognition – The process of using light-sensing equipment to scan paper and other media, and translate the patterns of light and dark (or color) into a digital signal for the computer. – Optical scanners are either flatbed scanners or handheld scanners. Optical-mark recognition (OMR) (score test results) Optical-mark recognition (OMR) (score test results) Optical-Bar recognition (OBR) Optical-Bar recognition (OBR) Optical scanners (used in combination with graphical software or optical-character recognition (OCR) software) Optical scanners (used in combination with graphical software or optical-character recognition (OCR) software)

56 56 Four Basic Components of a Computer System (continued) Output Unit n The process of translating machine-readable data into a form that can be understood by humans or a form that can be read by other machines is called output. n The information that is the result of processing is also referred to as output. n An output device is the hardware that enables a computer to communicate information to humans or other machines so that it may be used. n Output that people can read is categorized as either hard copy or soft copy.

57 57 Four Basic Components of a Computer System (continued) n Hard copy is a relatively stable and permanent form of output, such as paper, that can be read immediately or stored and read later. n Hard copy output devices include –printers –plotters –computer output microform (COM) devices (microfilm or microfiche cards).

58 58 Four Basic Components of a Computer System (continued) n Soft copy, for example, screen-displayed output or voice output, is a transient form of output. n soft copy output devices include –Monitors –voice-output n An input/output (I/O) device is used both to transfer data and instructions to the computer and to receive information from the computer. Terminals (keyboard and monitor) and disk drives are examples of input/output devices.

59 59 Four Basic Components of a Computer System (continued) Processing Unit n The system unit, or housing, contains the major components and controls of the computer. n Hardware that is extremely attached to the system unit is sometimes referred to as a peripheral device. n A central processing unit (CPU) is comprised of arithmetic-logic unit (ALU), and arithmetic-logic unit (ALU), and control unit. control unit.

60 60 Four Basic Components of a Computer System (continued) n The ALU handles mathematical and comparison operations. n The control unit regulates the timing and sequence of all processing within a computer. n Large system computers may contain many CPUs while a microcomputer usually has only one. n Large-system computers with more than one CPU have the ability to accomplish parallel processing, while microcomputers execute one instruction after another, called serial processing.

61 61 Four Basic Components of a Computer System (continued) n The computer’s main memory is the internal storage unit of a computer where programs and data are stored. n The two types of main memory are random-access memory (RAM) and read-only memory (ROM). n Random-access memory (RAM) is the part of main memory where data and program instructions are held temporarily while being manipulated or executed. nRAM is Read-write Read-write Volatile (when the power to a computer is shut off, everything in RAM is lost) Volatile (when the power to a computer is shut off, everything in RAM is lost)

62 62 Four Basic Components of a Computer System (continued) n Read-only memory (ROM) is the part of main memory that contain permanently stored instructions that tell a computer what to do when it is turned on, such as checking that everything is working properly and seeing what peripheral equipment is attached. nROM is Read only Read only Nonvolatile Nonvolatile

63 63 Four Basic Components of a Computer System (continued) Secondary Storage Unit n A secondary storage device is the nonvolatile memory used for keeping large amounts of data for permanent or large- term storage. n Secondary storage media also store backups, or copies of data and programs. n Three types of secondary-storage media are 1. magnetic tape, 2. magnetic disk (floppy diskette & hard disk), and 3. optical media (CD-ROM & WORM)

64 64 Four Basic Components of a Computer System (continued) nFour main characteristics of all secondary storage media are 1. capacity (total bytes & density), 2. access time (data access time & data transfer rate), 3. cost, and 4. compatibility interface.

65 65 What Is Software? nSoftware or computer program, are the instructions that cause the hardware to do the work that you desire. nThere are two main types of software: system software and application software. nSystem software directly controls and monitors the operation of the computer hardware. nApplication software allows you to perform a specific task or set of tasks.

66 66 What Is Software? (continued) nTasks include preparing documents, managing data, performing numeric calculations, creating graphic images, and transferring data between computers electronically. nThe types of application software that perform these tasks are word processors, database management systems, electronic spreadsheets, graphic programs, and communication programs. nApplication software also includes specialized tasks related to such fields as business, engineering, science, education, and entertainment. nFigure 1.4 shows the relationship among system software, application software, hardware, and the user.

67 67 What Is Software? (continued) Hardware User System software Application software Figure 1.4 The Relationship Among System Software, Application Software, Hardware, and the User

68 68 How Do Computers Transform Data into Information? nData are transformed into information through a series of steps referred to as Information processing, or data processing. nThese steps include (Figure 1.5) –input, –processing, –output, and –storage.

69 69 How Do Computers Transform Data into Information? (continued) Figure 1.5 The basic flow of data through a computer system involves three steps: (1) input, (2) processing, and (3) output. A user enters data at an input device, and the computer converts the data to machine-readable form. After the computer completes that procedure, the output, in human-readable form, prints out on the output device. Data can be stored during this flow.

70 70 How Do Computers Transform Data into Information? (continued) nInput refers to the data and instructions entered into a computer for processing or to the act of entering data, which is often called data entry.  It is important that data being input into the computer be accurate because they are the basis for producing the output generated.  If the input is incorrect the output will also be incorrect, creating a situation referred to as garbage in, garbage out (GIGO). nProcessing involves manipulating data into the desired from.

71 71 How Do Computers Transform Data into Information? (continued) nOutput refers to the results of processing and also describes the act of generating results. nStorage refers to the computer’s ability to maintain data or information for use at a later time.  A computer has two primary means of storage: internal storage called main memory, or primary storage, and external storage called secondary storage.  The instructions in a computer program and the data they work on must be stored in main memory to be executed.  Secondary storage preserves programs and data permanently or relatively permanently.

72 72 What Are the Limitation of Computer Use? nComputers cannot operate alone. nThey require humans to identify a problem, decide how to solve it, identify and collect the data to solve it, design the software to solve it, and interpret the information that is obtained.

73 73 How Do We Use Computers?

74 74 Objectives nTo identify and describe uses of the computer and indicate the advantages of using a computer in each.

75 75 General categories of Computers nThe uses of computers can be classified into eight general categories: Information systems / data processing Information systems / data processing Personal computing Personal computing Science, research, and engineering Science, research, and engineering Process / device control Process / device control Education Education Computer-aided design Computer-aided design Entertainment Entertainment Artificial intelligence Artificial intelligence

76 76 General categories of Computers (continued) nFigure 1.6 shows an estimate of how the sum total of existing computer capacity is apportioned to each of these general categories.

77 77 General categories of Computers (continued) Figure 1.6 The Way We Use Computers This pie chart is an estimate of how existing computer capacity is distributed among the general categories of computer usage.

78 78 General categories of Computers (continued) Information systems / data processing nThe computer is used to process data and produce business information. nExample applications include payroll systems, airline reservation systems, student registration systems, and hospital patient-billing systems. nHardware, software, people, procedures, and data combine to create an information system.

79 79 General categories of Computers (continued) Personal computing nThe single-user microcomputer is used for a variety of business and domestic applications. nThe family of productivity software is the foundation of personal computing in the business world and in the home, such as Word processing software enables users to enter text, to store it on magnetic storage, to manipulate it in preparation for output, and to produce a hard copy (printed output). Word processing software enables users to enter text, to store it on magnetic storage, to manipulate it in preparation for output, and to produce a hard copy (printed output).

80 80 General categories of Computers (continued) Desktop publishing software allows users to produce near-typeset- quality copy for newsletters, advertisements, and many other printing needs, all from the confines of a desktop. Desktop publishing software allows users to produce near-typeset- quality copy for newsletters, advertisements, and many other printing needs, all from the confines of a desktop. Spreadsheet software permits users to work with the rows and columns of a matrix (or spreadsheet) of data. Spreadsheet software permits users to work with the rows and columns of a matrix (or spreadsheet) of data. Database software permits users to create and maintain a database and extract information from the database. Database software permits users to create and maintain a database and extract information from the database. Graphics software facilitates the creation and management of computer-based images such as pie graphs, line drawings, company logos, maps, clip art, and blueprints. Graphics software facilitates the creation and management of computer-based images such as pie graphs, line drawings, company logos, maps, clip art, and blueprints.

81 81 General categories of Computers (continued) nThis area of computing is often referred to as personal computing. nPersonal computers can be used as stand-alone computer systems or as remote terminal. nDual-function personal computers can be used in conjunction with the telephone to transmit data to and receive data from an information network. nInformation networks permit such applications as electronic mail ( ) and home shopping where payment may be made via electronic funds transfer (EFT).

82 82 General categories of Computers (continued) Science, research, and engineering nThe computer is used as a tool in experimentation, design, and development.

83 83 General categories of Computers (continued) Process / device control nApplications that involve process/device control accept data in a continuous feedback loop. nAn automated traffic-control system is a good example of he continuous feedback loop in a computerized process-control system. –In a continuous feedback loop, street sensors provide input to a process-control computer system about the direction and the volume of traffic flow. Based on their feedback, the system controls the traffic lights to optimize the flow of traffic.

84 84 General categories of Computers (continued) Education nThe computer interacts with a student to enhance the learning process. nComputer-based training (CBT) is having a profound impact on traditional modes of education. –Through interactive computer graphics, a CBT system can demonstrate certain concepts more effectively than books or teachers. –CBT programs can help you to learn keyboarding skills, increase your vocabulary, study algebra, learn about the makeup of the atom, and practice your Russian.

85 85 General categories of Computers (continued) Computer-aided design nComputer-aided design (CAD) is using the computer in the design process. nCAD systems –enable the creation and manipulation of an on screen graphic image. –provide a sophisticated array of tools enabling designers to create three-dimensional objects that can be flipped, rotated, resized, viewed in detail, examined internally or externally.

86 86 General categories of Computers (continued) Entertainment nEvery day, computer applications are being designed and created just to entertain us.

87 87 General categories of Computers (continued) Artificial Intelligence nArtificial Intelligence (AI) involves creating computer systems with the ability to reason, to learn or accumulate knowledge, to strive for self-improvement, and to simulate human sensory and mechanical capabilities. nThere are four categories of AI research (Figure 1.7): –knowledge-based and expert systems, –natural languages, –simulation of human sensory capabilities, and –robotics.

88 88 General categories of Computers (continued) Figure 1.7 Categories of Artificial Intelligence

89 89 General categories of Computers (continued) nKnowledge-based and expert systems  A Knowledge-based system relies on a knowledge base that is filled with "rules of thumb" (intuition, judgment, and inferences) about a specific application area, such as automobile repair.  Humans can use the knowledge-based system and the IF-THEN rules in the knowledge base to help them solve a particular problem.  Expert systems are the most sophisticated implementation of a knowledge-based system.  Once the knowledge of one or more human experts has been entered to an expert system's knowledge base, users can tap this knowledge by interacting with the system in much the same way they would interact with a human expert in that field.

90 90 General categories of Computers (continued)  Both the user and the computer-based expert system ask and respond to each other's questions until a problem is resolved.  Expert system have been developed to support decision makers in a broad range of disciplines, including - automobile repair, - medical diagnosis, - oil exploration, - financial planning, - chemical analysis, - surgery, - locomotive repair, - weather prediction, - computer repair, - trouble-shooting satellites, - computer systems configuration, - operation of nuclear power plants, - newspaper layout, - interpreting government regulations, and - tax preparation.

91 91 General categories of Computers (continued) nNatural languages  Natural languages refer to software that enables computer systems to accept, interpret, and execute instructions in the native, or “natural,” language of the end user.

92 92 General categories of Computers (continued) nSimulation of human sensory capabilities  This area focuses on equipping computer systems with the capabilities of seeing, hearing, speaking, and felling (touching).

93 93 General categories of Computers (continued) nRobotics  Robotics is the integration of computers and robots.  Industrial robots, which are usually equipped with an arm and a hand, can be “taught” to perform almost any repetitive manipulative task, such as painting a car, screwing on a bolt, moving material, and even such complex tasks as inspecting a manufactured part for defects.

94 94 Characteristics of Information Processing System Components

95 95 Objectives 1.Specify the criteria used to categorize computers. 2.Describe the major computer categories. 3.Describe the different types of microcomputers. 4.Distinguish between microcomputers, workstations, minicomputers, mainframes, and supercomputers.

96 96 Types of Processors n Special-purpose - accept a limited set of inputs, and process them in a limited set of ways. n Embedded - type of special-purpose processors that are contained in other products. n General-purpose - designed to accept a wide variety of inputs, accomplish a wide variety of processing activities, and deliver a wide variety of outputs.

97 97 Processing Power n We view processing activity as one which first requires the accessing of data and instructions and then requires the execution of the selection, organization, and manipulation operations. n Processing power - defined as the speed at which this activity can occur.  MIPS - millions of instructions per second.  MHz - millions of cycles per second.  MFLOPS - millions of floating-point operations per second.

98 98 Processing (Main) Memory n The capabilities of main memory are a direct function of processor access time and storage capacity. n Storage capacity is measured in:  Byte - one byte is equal to one character (B)  Kilo approximately 1 thousand (K)  Mega approximately 1 million (M)  Giga approximately 1 billion (G)  Tera approximately 1 trillion (T)

99 99 Computer Systems Come in all Shapes and Sizes n The criteria for classifying computers include  Architecture (design of the internal circuitry),  processing speed (MIPS),  amount of main memory,  capacity of external storage devices,  speed of output devices,  number of users that can access a system at one time, and  cost.

100 100 Computer Systems Come in all Shapes and Sizes (continued) n According to these criteria, computers are grouped into five size classifications: 1.microcomputers 2.workstations 3.minicomputers 4.mainframes 5.supercomputers

101 101 Computer Systems Come in all Shapes and Sizes (continued) nThe most distinguishing characteristic of any computer system is its size - not its physical size, but its computing capacity. nDepending on their sophistication, a workstation’s computing capacity falls somewhere between that of a micro and a main frame. nSmall computers are classified as microcomputers and workstations. nLarge computers are categorized as supercomputers, mainframe computers, and minicomputers.

102 102 Computer Systems Come in all Shapes and Sizes (continued) nAll computers, no matter how small or large, have the same fundamental capabilities – processing, storage, input, and output. nThe number of companies manufacturing a particular category of computer increases as the size of computer decreases. nFigure 1.8 illustrates how various computer systems overlap in computing power.

103 103 Computer Systems Come in all Shapes and Sizes (continued) Figure 1.8 Because technological advanced have increased computing power and decreased prices, categorical distinctions among computer systems are becoming increasingly blurred

104 104 Single-User vs. Multiuser Systems n Single-user systems are information processing systems primarily designed to support only one end user at any one time. n Multiuser systems are more powerful in that they allow many people to share the same set of data and programs without having to duplicate it for each individual.

105 105 Microcomputers: Small but Powerful n Microcomputers - primarily designed for single users, hence their alternative name of personal computer (PC) systems; microcomputer systems are most popular.  desktop computer systems  laptops  notebooks and sub-notebooks  palm-size (PDA’s)  tower PCs. n Continuous improvements in microelectronics and computer technology promise to deliver ever greater processing power in ever smaller units.

106 106 Microcomputers: Small but Powerful (continued) nA microcomputer is a computer that is built around a single-chip processor called the microprocessor. nIn a microcomputer, the microprocessor, the electronic circuitry for handling input/output signals from the peripheral devices (keyboard, printer, and so on), and the memory chips are mounted on a single circuit board called a system board, or motherboard. nThe computer and its peripheral devices are called the computer system configuration.

107 107 Microcomputers: Small but Powerful (continued) nA typical micro configuration consists of the following: 1. A microcomputer 2. A keyboard and a point-and-draw device for input 3. A monitor for soft-copy (temporary) output 4. A printer for hard-copy (printed) output 5. magnetic disk drives for permanent storage of data and programs

108 108 Microcomputers: Small but Powerful (continued) nMicro users have the flexibility to configure their systems with a variety of peripheral devices because of the system’s open or bus architecture. nThe electrical bus is the path through which the processor sends and receives data and commands to RAM and all peripheral. nA port provides a direct link to the micro’s bus. nExternal terminal peripheral devices are interfaced with the processor through either a serial port or a parallel port.

109 109 Microcomputers: Small but Powerful (continued) nSerial ports –facilitate the serial transmission of data, one bit at a time. –provide an interface for low-speed printers and modems. nParallel ports –facilitate the parallel transmission of data, several bits are transmitted simultaneously. –provide an interface for high-speed printers, magnetic tape backup units, and other computers. nMicros can be used as stand-alone computer systems, or they can serve as “intelligent” terminals to mainframe computers.

110 110 Workstations: The Hot Rods of Computing nSpeed, the sophistication of its input/output devices, and its operating system set the workstation apart from a PC. nThe operating system monitors and controls all input/output and processing activities within a computer system. nThe workstation’s operating system enables it to handle complex processing activities simultaneously and makes it easier to work in harmony with other computers in a network.

111 111 Workstations: The Hot Rods of Computing (continued) nWorkstations - single-user systems that provide a large amount of processing power and typified by high-quality display devices. nCommon applications for workstations include computer-aided design (CAD) and software development.

112 112 Minis and Mainframes: Corporate Workhorses nMinicomputers bridge the gap between micros and mainframes. nMinicomputer is described as the smallest computer designed specifically for the multiuser environment. n Minicomputers - midrange systems that are physically smaller and less expensive than mainframe systems.  are faster and more powerful than some of their older mainframe counterparts  trend towards smaller computer systems  processing power of smaller computer systems has dramatically increased  advanced telecommunications technologies now allow smaller computers to communicate with each other

113 113 Minis and Mainframes: Corporate Workhorses (continued) nMinicomputers usually serve as stand-alone computer systems (Figure 1.9) for small businesses (10 to 400 employees) and as remote departmental computer systems.

114 114 Minis and Mainframes: Corporate Workhorses (continued) Figure 1.9 A Minicomputer System

115 115 Minis and Mainframes: Corporate Workhorses (continued) nMainframes are the category between minicomputers and supercomputers. nAside from the obvious differences in processing speed, the major difference between minicomputers and mainframes is the number of remote terminals serviced. nA computer servicing more than 200 terminals is no longer considered a minicomputers.

116 116 Minis and Mainframes: Corporate Workhorses (continued) n Mainframes - large computer systems that can accommodate hundreds of users doing different computing tasks  applications are large and complex  main memory can store hundreds of millions of characters  used by government agencies, banks, universities, and insurance companies

117 117 Minis and Mainframes: Corporate Workhorses (continued) nThe operator console in the machine room is used to communicate instructions to mini and mainframe computer systems. nA typical mainframe configuration might have a host processor, a front-end processor, and perhaps a back- end processor (Figure 1.10).

118 118 Minis and Mainframes: Corporate Workhorses (continued) Figure 1.10 Mainframe Computer System

119 119 Supercomputers: Processing Giants nMainframe computers are input/output-bound. nIn contrast, supercomputers handle the types of applications helpful to engineers and scientists. nThese applications are typically processor-bound and require relatively little in the way of input or output.

120 120 Supercomputers: Processing Giants (continued) n Supercomputers - largest, fastest, and generally the most expensive available.  main memory can store hundreds of millions of characters  large businesses and government agencies have them  popular for advanced scientific calculations  used for weather forecasting, engineering, and other situations where it is necessary to process a lot of data quickly

121 121 Supercomputers: Processing Giants (continued) nThere are supercomputer applications:  Simulation of airflow around an airplane at different speeds and altitudes.  Simulation auto accidents on video screens (Auto manufactures).  Studying the results of explosions of nuclear weapons (Physicists).  Hollywood production studios use advanced graphics to create special effects for movies and TV commercials.


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