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Chapter 1 Computer Overview

Chapter 1 Computer Overview. 1.1 History of Computing Machines 1.2 Invention of Computer 1.3 Computer Generations of Computer 1.4 Types of Computer. 1.1 History of Computing Machines. 3000 B.C. the Sumerians used a box of stones as a device for representing numbers.

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Chapter 1 Computer Overview

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  1. Chapter 1 Computer Overview 1.1 History of Computing Machines 1.2 Invention of Computer 1.3 Computer Generations of Computer 1.4 Types of Computer

  2. 1.1 History of Computing Machines 3000 B.C.the Sumerians used a box of stones as a device for representing numbers 2500 years agoThe abacus, invented by the Chinese 1642 The first mechanical calculator was invented by Blaise Pascal, a French mathematician In early 1700sThe first general-purpose calculating machine was Leibniz Wheel introduced 1822 A British mathematician, Charles Babbage, designed a machine that he called the difference engine, for calculating certain types of mathematical tables A machine based on Babbage's ideas was completed in 1855 and used in the United States and Great Britain.

  3. 1.2 Invention of Computer ＊Starting in the 1930s and through the 1940s, a number of machines were developed that were like a computer. ＊One of the first computer-like devices was developed in Germany by Konrad Zuse in 1941. Called the Z3＊Another electromechanical computing machine was developed by Howard Aiken, with financial assistance from IBM, at Harvard University in 1943. ＊During World War II, a team of scientists and mathematicians, working at Bletchley Park, north of London, created one of the first all-electronic digital computers—Colossus ＊Perhaps the most influential of the early computer like devices was the Electronic Numerical Integrator and Computer, or ENIAC (1943)

  4. 1.3 Computer Generations of Computer 1.3.1 First-Generation Computer: 1951—1958First-generation computers were characterized by the use of vacuum tubes as their principal electronic component 1.3.2 Second-Generation Computer: 1959—1963In the second generation of computers, transistors replaced vacuum tubes. 1.3.3 Third-Generation Computer: 1964—1970The technical development that marks the third generation of computers is the use of integrated circuits or ICs in computers. 1.3.4 Fourth-Generation Computer: 1971—PresentThe microprocessor brought the fourth generation of computers. This generation is characterized by more and more transistors being contained on a silicon chip. 1.3.5 Fifth-Generation Computer (Future Development)The fifth-generation computers will be intelligent computers capable of reasoning similar to that of a person.

  5. 1.4 Types of Computer They can be divided into several categories on the basis of cost and performance: ＊microcomputerThey are relatively inexpensive machine that can fit on a desktop, or can be carried around＊workstationThey are expensive and powerful desktop computers used mainly by engineers, scientists, and special-effects creators for sophisticated purposes. ＊minicomputerTheir capabilities are suited to a business, school, or laboratory.＊mainframeA mainframe, which also has many processors, can support hundreds, or even thousands, of users simultaneously. ＊supercomputer. They may occupy special air-conditioned rooms and are often used for scientific research

  6. Chapter 2 Computer Hardware 2.1 Processing Hardware 2.2 Input Device 2.3 Output Device 2.4 Storage Unit

  7. 2.1 Processing Hardware Computer's control center is made up of the processing and main memorydevices CPU: The control unitandthe arithmetic/logic unit.interprets the instructions given to it by software, and carries out these instructions by processing data and controlling the rest of the computer's components. The control unitinforms other components of the computer system how to carry out a program's instructions The arithmetic/logic unit, orALU, performs arithmetic operations and logical operations and controls the speed of those operations There are some registersin the CPU that are used for storing data temporarily during execution of instructions

  8. Chip design Three processor architectures are adapted in chip design:CISC, RISC, MPP. CISC stands for complex instruction set computer, which is found in most conventional mainframes and personal computers RISC, for reduced instruction set computer, refers to a processors that support fewer instructions than do CISC chips. Massively parallel processing (MPP), which spreads calculations over hundreds or even thousands of standard microprocessors Memory is temporary working storage, which is also named as primary storage, main memory, and RAM. RAM is used for holding data and programs needed for immediate processing

  9. 2.2 Input Device 2.2.1 Keyboards2.2.2 Mice and Pens 2.2.3 Scanners 2.2.4 Voice Recognition

  10. 2.2.1 Keyboards A computer keyboard includes keys for letters, digits, and special symbols. The standard keyboard, is divided into four sections:＊ Standard typing keys,＊ Function keys, ＊ Cursor-movement keys,＊ Numeric keypad.. The typing keys usually locate in the left of a keyboard, whose function is very alike that of typewriter. All computer keyboards have a row of numbersacross the top. Cursor-movement keys are in a separate keypad or may be part of the numeric keypad. Functional keys are labeled with F and a number.

  11. 2.2.2 Mice and Pens Non-keyboard input devices ＊ Electronic mice＊ Light pens＊ Touch screens＊ Graphics tablets An electronic mouse is a palm-sized device that can be moved across a flat surface to direct a pointer on a display screen. Lightpen—a pencil-like light sensitive rod that can be pointed at a display screen, and then pressed, to activate various functions. Display screens allow the touch a finger to activate a function.

  12. 2.2.3 Scanners Optical scanners use visible light to read characters, numbers, or patterns. ＊Optical mark reader＊Optical character reader＊Bar-code reader＊Graphics ＊Desktop scanners. An optical mark reader (OMR) senses marks on special paper forms. The optical character reader (OCR), can detect special OCR character sets called OCR fonts A bar-code reader is a scanner that reads data coded as vertical lines (bars) of varying width. Flatbed and drum scanners are used for scanning high-quality color graphics. FAX , short for facsimile transmission machines, allow text to art to be electronically sent from one location to another.

  13. 2.2.4 Voice Recognition A voice recognition device can translate the human voice into signals for use as input media A voice recognition system uses a microphone (or a telephone) as an input device to convert a person's speech into digital code, by comparing the electrical patterns produced by the speaker's voice with a set of prerecorded patterns stored in the computer.

  14. 2.3 Output Device 2.3.1 Monitors2.3.2 Printers2.3.3 Other Output Devices

  15. 2.3.1 Monitors Two common monitors are:(1) Cathode-ray tubes (CRTs), which are like television picture tubes; (2) flat-panel displays made of LCD, which are much thinner, weight less, and consume less power. CRTs are used with both microcomputers and display terminals and tend to be bulky. Flat-panel displays in contrast, are very thin, making them ideal for lightweight portable microcomputers. Flat-panel displays are not bulky as CRTs, the images displayed on them are not always as good as CRT images. You may view flat-panel images unclearly from an angle.

  16. 2.3.2 Printers Print quality and speed are two factors for valuating a printer. Impact printers have printing mechanisms that physically contact the paper. Dot-matrix printers, which offer considerable flexibility, were once the most popular type of printer used with PCs. Large computers use line printers that can complete hard copy at a rate of 3000 lines per minute. Nonimpact printers are so called because their printing mechanism does not touch the paper. Ink-jet Printers use electrically charged ink droplets to form "near- letter-quality" images on the paper. High-speed page printers primarily using laser-xero-graphic technology, produce an entire output page at one time.

  17. 2.3.3 Other Output Devices Many simpler printers also can produce graphics. Plotters are specialized devices that output high-quality graphics in various colors. Audio output devices allow the user to listen to the computer.

  18. 2.4 Storage Unit 2.4.1 Magnetic Storage Media 2.4.2 Optical Storage Devices 2.4.3 Flash Memory

  19. 2.4.1 Magnetic Storage Media Magnetic media includes tapes, diskettes, and hard disks. Magnetic tape was ever the main storage device in early computers, and it is still used for back up and archiving of data for large computer systems. Diskettes and hard disks adopt random access method in reading and writing information. Hard disks are most important online storage medium. They are rigid metal platters sealed inside the hard disk drives, which are built in to the system unit, so they are not fragile as diskettes.

  20. 2.4.2 Optical Storage Devices The optical disk technology used with computers can be categorized as four main types: ＊ CD-ROM disks＊ CD-R disks＊ CD-RW disks＊ DVD/DVD-ROM. CD-ROM is a read-only disk that the disk's content is recorded at the time of manufacture and cannot be written on or erased by the user. CD-R (Compact Disk-Recordable) is a CD format that allows users with CD-R drives to write data, only once, onto a specially manufactured disk. CD-RW (Compact Disk-Rewritable) format allows user to erase data so that this disk can be used over and over again DVD, which stands for digital video disc or digital versatile disk, is the newest optical disc format.

  21. 2.4.3 Flash Memory Flash memory is the result of revolution in secondary storage technology, and is frequently used in recent years . Flash memory is derived from EEPROMs (Electrically Erased Programmable ROM) and used primarily in portable computers

  22. Chapter 3 Operating System 3.1 Opening Remarks 3.2 How an Operating System works 3.3 Generations of Operating Systems 3.4 Common Operating Systems 3.5 Future Trends

  23. 3.1 Opening Remarks Operating systems today are used on computers ranging in size from giant mainframes to small personal computer. We view an operating system as the programs, implemented in either software or firmware, which make the hardware usable OS resides in RAM while the computer is turned on and provides resource management services of many kinds. The operating system allows you to concentrate on your own tasks or applications rather than on the complexities of managing the computer

  24. 3.2 How an Operating System works <1>The operating system is automatically loaded into main memory soon after you boot the computer . <2>Bootstrap loader performs an automatic power-on self-test (POST) that usually tests RAM, the keyboard, and the disk drives. <3>Once POST is successfully completed, BIOS initiates a search for the operating system <4>When it finds the operating system, it loads the operating system's kernel into the computer system. Operating system control different computer processes, such as running a word processing application, accessing information from the computer's memory, and dealing with data input and output of peripheral devices. Operating systems are either single-tasking or multitaskingSingle-tasking operating system can run only one application program at one time, which user find very inconvenient. All modern operating systems are multitasking, which enable a user to work with two or more programs simultaneously.

  25. 3.3 Generations of Operating Systems The Zeroth Generation (1940s)Early computing systems had no operating system.The First Generation (1950s)First generation of OS is single-tasking batch operating systemsThe Second Generation (Early 1960s)Second generation of operating systems was characterized by the development of shared systems with multiprogrammingThe Third Generation (Mid 1960s to mid 1970s)Third generation of operating systems effectively began with the introduction of the IBM System/360 family of computers in 1964The Fourth Generation (Mid 1970s to Present)Fourth generation systems are the current state of the art. With the widespread use of computer networking and on-line processing, users gain access to networks of geographically dispersed computers through various types of terminals.

  26. 3.4 Common Operating Systems 3.4.1 DOSMS-DOS and PC-DOS are the most widely used single-tasking operating systems 3.4.2 UNIX Operating SystemUNIX is one of the most well-known multitasking operating systems that were originally developed for the minicomputer market.3.4.3 Linux Operating SystemLinux is clone of UNIX, which offers UNIX's power but was developed as freeware by Linus Torvalds and a team of programmer over the Internet.3.4.4 Windows Operating SystemWindows is a personal computer operating system developed by Microsoft Corporation.

  27. 3.5 Future Trends (1) Computer hardware will continue to decline in price, while processor speeds increase, storage capacities increase, and the physical size of processors and memories decreases. (2) The "scale of integration" will continue to increase with VLSI (very large-scale integration) moving to ULSI (ultra large-scale integration) over the next decade. (3) Multiprocessing will become much more common. (4) Many of the operating systems functions now performed by software will migrate into micro-code. (5) Hardware architecture of the future will distribute control into localized processors. (6) Languages are being developed to exploit concurrence, while hardware and operating systems are being designed to execute concurrent programs more efficiently. (7) Massive parallelism will become common. It will become possible to execute parallel programs with great speed because of the very high degree of concurrence. (8) Developments in software engineering will result in operating systems that are more maintainable, reliable, and understandable. (9) The cost of data communications will continue to decrease, and data transmission speeds will increase. (10) Computers will be tied increasingly into networks, and work performed for a user may be done on a computer of which the user is unaware. This will continue to emphasize the importance of the views of virtual machines. (11) The concept of distributed processing will cause the development of dispersed operating systems in which operating system functions are distributed among many processors throughout large networks.

  28. Chapter 4 Computer Language and Programming 4.1 Computer Programming Language 4.2 Program Development 4.3 Language Structure and Components 4.4 Object-Oriented and Visual Programming

  29. 4.1 Computer Programming Language 1. Machine LanguageMachine language is a low-level language, which consists of binary numbers 1s and 0s that directly correspond to the computer's electrical states 2. Intermediate Language: Assembly LanguageAssembly language allows a programmer to use brief abbreviations or easily remembered words instead of numbers.3. High-level LanguageA high-level language is an English-like language, which eliminates the need for programmers to understand the internal details of computer.

  30. 4.2 Program Development A compute program is a set of instructions that directs a computer to perform some processing functions or combination of functions. Generally, the program developing process includes four steps: (1) editing source program(2) compiling source codes to generate object codes(3) linking the object file with library routines to produce execution file(4) running execution file and debugging.

  31. 4.3 Language Structure and Components Statements, or instructions, are used to provide functional structure to the program. Any program is organized with combination of three basic control structures: sequence control structureIn a sequence control structures, instructions are executed in the order in which they appear.repletion (loop or iteration) control structure In a loop control structure, the program repeats the same instructions over and over. selection control structure. In a selection control structure, computers perform different instructions based on the values of data being processed. The most common subroutines are functions, procedures, library routines, system routines, and device drivers.

  32. 4.4 Object-Oriented and Visual Programming Object-oriented programming (OOP) is a programming language model organized around "objects" rather than "actions" and data rather than logic. OOP combines data and instructions for processing that data into a self-sufficient "object". Objects are further grouped into classes, which define the attributes objects must have One of the first object-oriented computer languages was called Smalltalk. C++ and Java are the most popular object-oriented languages today. Visual programming is a method of creating programs by using icons that represent common programming routines. The programmer makes connections between objects by drawing, pointing, and clicking on diagrams and icons and by interacting with flowcharts.

  33. Chapter 5 Data Structure 5.1 Basic Concepts 5.2 Fundamental Data Structures 5.3 Data Sorting

  34. 5.1 Basic Concepts 5.1.1 Data Type A data type is a type together with a collection of operations to manipulate the type. A distinction should be made between the logical concept of a data type and its physicalimplementation in a computer program 5.1.2 Abstract Data Type (ADT) An abstract data type (ADT) is the realization of a data type as a software component. A data structure is the implementation for an ADT. The concept of an ADT can help us to focus on key issues even in non-computing applications .The ADT is implemented in one part of the program by a particular data structure.

  35. 5.2 Fundamental Data Structures 5.2.1 Lists5.2.2 Stack 5.2.3 Queues

  36. 5.2.1 ListsWe define a list to be a finite, ordered sequence of data items known as elements. Each list element has a data type. In the simple list implementations, all elements of the list have the same data type, although there are lists whose elements have differing data types if the application requires it. 5.2.2 StackA stack is one of the most frequently used and most important datastructures. At a lower level, stacks are used to pass parameters to functions and to make the actual function call to and return a function. 5.2.3 QueuesLike the stack, a queue is a list-like structure that provides restricted access to its elements. Queue elements may only be inserted at the back (called an enqueue operation) and removed form the front (called a dequeue operation) queues operate like standing in line at a movie theater ticket counter.

  37. 5.3.1 Why SortingOrdering of data records gives a very convenient visual representation, from which it is easy to find particular desired entries.5.3.2 SelectionThis method is known as selection sorting at each step, the record with the highest key is selected from among those records remaining.5.3.3 BubbleThe bubble sort involves, at all stages, only comparisons of adjacent records. Thus a worthy record initially located toward the end of a vector cannot, as in selection sort, suddenly move up at the start; it must proceed a single step at a time, slowly bubbling to the top. 5.3 Data Sorting

  38. Chapter 6 Communication and Networking 6.1 Data Communication 6.2 Distributed Processing 6.3 Network Topologies 6.4 Network Protocol 6.5 LAN

  39. 6.1 Data Communication Data communications is the transmission, reception, and validation of data. Networks are a combination of computers and peripherals linked together for the purpose of data communications. Data communications provides rules that allow computers with different operating systems, languages, cabling and locations to share resources. Many applications are served by data communications networks. Data communications networks can help support time-sharing, real time processing, batch processing, or a combination of the three.

  40. 6.2 Distributed Processing The reason why distributed processing computers appear. Distributed processing seeks a middle path between the centralized and decentralized approaches. Distributed processing spreads information-processing capabilities throughout an organization. In most corporations, distributed processing had led to a three-tier division of computing responsibilities

  41. 6.3 Network Topologies The four basic topologies are star, ring, bus, and hierarchical network. Different topology varies in costs and network performance. In a star network, a central connection point is connected to remote peripherals or other computers, which are not connected to each other. A ring network links computers into a loop, without central computer; instead, all of the computers are equal and communicated with one another. A bus network uses a common cable called bus to link computers and peripherals. The hierarchical network has a main computer at its top, the most important level in terms of control. Communication links spread downward and outward much like the roots of a tree

  42. 6.4 Network Protocol A protocol, or communication protocol, is a set of conventions governing the exchange of data between hardware and/or software components in a communications network. Protocol perform several important network functions, including: (1) dividing messages into packets; (2) affixing addresses to packets;(3) initiating transmission; (4) regulating the flow of data; (5) acknowledging receipt of transmitted data. The best-known protocol is probably TCP/IP.TCP/IP refers to two network protocols used on the Internet. They are Transmission Control Protocol and Internet Protocol, respectively.

  43. 6.5 LAN Local Area Network (LANs)—sometimes simply called local networks—provide offices with the capability of data communications in a smaller setting. Microcomputers linked together in a LAN can share peripheral devices such as sophisticated printers and secondary storage systems or expensive software, making it possible to justify devices that a single microcomputer user might not be able to afford. The two prevalent types of LANs in organizational structures are client/server and peer-to-peer (p2p). The most widely used LAN, Ethernet, uses CSMA/CD protocol (Carrier Sense Multiple Access with Collision Detection).

  44. Chapter 7 Developing Information Systems 7.1 System Planning 7.2 System Analysis 7.3 System Design 7.4 System Implementation 7.5 System Maintenance 7.6 Information System Development Tools

  45. 7.1 System Planning System planning is the first phase of the system development process, in which the systems analyst plans what information system will be developed. ＊Information systems grow and change to reflect the evolving needs of an organization. ＊Next, a systems analyst must carefully define the problem, distinguishing it from its symptoms.＊After the need for an information system has been recognized, the systems analyst must determine if it is feasible to develop the system, a process called feasibility analysis. ＊After completing the feasibility analysis, the analyst should prepare written documentation of the results.

  46. 7.2 System Analysis After the systems analyst has decided that a new system is feasible, he or she must analyze the system to determine what it must do Systems analysts create data flow diagrams, data dictionaries, and process specifications to document the way in which a system works. An analyst determines requirements by interviewing users and studying successful information systems that solve problems similar to those found in the current systems. One of the biggest problems in system analysis is to understand the user's requirements.

  47. 7.3 System Design The analyst specifies the details of the design (1) Layouts of all screens, reports, and forms. (2) Organization of all records, files, and databases. (3) Descriptions of all programs. (4) Descriptions of all manual procedures. (5) Specifications for all hardware. (6) Descriptions of all personnel. In order to produce applications more quickly than traditional programming language, application development tool is often used. An application development tool is essentially a type of software construction kit that contains building block。

  48. 7.4 System Implementation 1. Acquiring the components of the new systems If new hardware is to be purchased, however, then alternative equipment that meets the hardware specifications is evaluated and a selection is made. 2. Testing the systemNew hardware can either replace old equipment or be connected to existing equipment. In either case, it must be tested to ensure that it operates correctly.3. Installing the new system, converting from the old system to the new systemThe final activity of this step is to convert from the old system to the new system. The change is usually made gradually by phasing in a part of the new system at a time.

  49. 7.5 System Maintenance After a system has been operating for a while, it may have to be modified, which is the process of system maintenance. Maintenance is required for three reasons.＊The first is that errors are found that were not detected when the system was tested. Even though the system was thoroughly tested, errors often appear after the system has been in use for a while. ＊The second reason is that a new function is to be added to the system. For example, the preparation of a new report may be needed. ＊The final reason for system maintenance is that requirements change. Systems analysts and programmers usually do most of the work, but hardware specialists, managers, technical writers, equipment operators, and trainers may also be involved.

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