计算机科学导论(全英版)课后问答

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计算机导论课后习题问题详解

计算机导论课后习题问题详解

计算机导论课后习题答案汇编第一章一、简答题1、什么是计算机?计算机系统是一种能够按照事先存储的程序,自动、高速的对数据进行输入、处理、输出和存储的系统。

一个计算机系统包括硬件和软件两大部分。

2、解释·诺依曼所提出的“存储程序”概念。

把程序和数据都以二进制的形式同意存放在存储器中,由机器自动执行。

不同的程序解决不同的问题,实现了计算机通用计算的功能,3、计算机有哪些主要的特点?运算速度快`精度高计算机的字长越长,其精度越高,现在世界上最快的计算机每秒可以运算几十万次以上。

一般计算机可以有市纪委甚至几十位(二进制)有效数字,计算精度可由千分之几到百万分之几,是任何计算工具所望尘莫及的。

具有逻辑判断和记忆能力计算机有准确的逻辑判断能力和高超的记忆能力。

能够进行各种逻辑判断,并根据判断的结果自动决定下一步应该执行的指令。

高度的自动化和灵活性计算机采取存储程序方式工作,即把编号的程序输入计算机,机器便可依次逐条执行,这就使计算机实现了高度的自动化和灵活性。

4、计算机有哪些主要的用途?(1)科学计算(2)数据处理(3) 实时控制(4)人工智能(5)计算机辅助工程和辅助教育(6)娱乐和游戏5、计算机发展中各个阶段的主要特点是什么?第一代计算机特征是采用电子管作为主要元器件第二代计算机特征是采用晶体管作为主要器件第三代计算机特征是半导体中小规模集成电路第四代计算机特征是大规模和超大规模集成电路6信息化社会的主要特点是什么?1·建立完善的信息基础设施2·采用现金的信息技术3·建立广泛的信息产业4·拥有高素质的信息人才5·构建良好的信息环境7、信息化社会对计算机人才的素质和知识结构有哪些要求?在信息化社会中所需要的计算机人才是多方位的,不仅需要研究型、设计型的人才,而且需要应用型的人才;不仅需要开发型人才而且需要维护型、服务型、操作型的人才。

要求计算机人才具有较高的综合素质和创新能力,并对于新技术的发展具有良好的适应性。

大学计算机基础课课本计算机科学导论课后答案

大学计算机基础课课本计算机科学导论课后答案

大学计算机根底课课本计算机科学导论课后答案以下答案多方资料做的,仅供参考。

第一章绪论1. 和计算机相关的问题.2. 冯.诺依曼模型.3. 第一点:尽管这个模型能够表达现代计算机的功能,但是它的定义太广泛. 第二点:而且,并没有清楚地说明基于这个模型的机器能够完成的操作类型和数量.4. 输入数据和程序.5. 存储器,算术逻辑单元,控制单元和输入/输出单元.6. 存储器是用来存储的区域,在计算机处理过程中用来存储数据和程序.7. 算术逻辑单元是进行计算和逻辑判断的地方.8. 控制单元是用来对存储器,算术逻辑单元,输入/输出单元等子系统的操作进行控制的单元.9. 输入子系统负责从计算机外部接受输入数据和程序;输出子系统负责将计算机的处理结果输出到计算机外部.10. 早期的计算机的存储器存储数据.而完成某一任务的程序是通过操作一系列的开关或改变配线系统来实现的.而基于冯.诺依曼模型的计算机的存储器主要用来存储程序及其相应的数据.11.编程在早期的计算机中表达为对系列开关的开闭和配线系统的改变.而冯.诺依曼模型通过详细的第一计算机可以使用的不同指令集,从而使编程变得相对简单.程序员通过组合这些不同的指令来创立任意数量的程序. 12. B 13. C 14. A 15. B 16. D从而改变了编程的概念.17. C 18. D 19. C 20. A 21. D 22. A 23. C 24. D 25. D 26. D第二章略第三章数的表示1. 将十进制转换成二进制,那么反复采用底数除法.将要转换的数反复除2,所得余数做为从右往左的数.直到除数为1,作为最左端的数.2. 将所给的二进制的数每个二进制数字分别乘以它的权值,最后将每个二进制位乘以权值后的结果相加即得到相应的十进制数. 3. 第N位是2的N-1次幂.4. 第N位是10的N-1次幂.5. 符号加绝对值格式,二进制反码格式和二进制补码格式.6. 计算机定义一个最大的无符号整数的常量,这样,计算机所能存储的无符号整数就介于0到该常量之间.也就定义了一个存值范围.7. 位数分配是指用以表示整数的二进制位数.8. 因为8位的存储单元中,范围最大的无符号整数类型的范围是0~255,256超出其存储范围,在计算机中不能存储. 9. 计数和寻址.10. 溢出. 11. 一样.12. 符号加绝对值:在N位的存储单元中,将该负数忽略其负号,然后转换成N-1位的二进制数,缺乏位数左边补0.最后在最左边加1.二进制反码:在N位的存储单元中,将该负数忽略其负号,然后转换成N位的二进制数,缺乏位数左边补0.最后,将其每一位换成它D 31. C 32. B 33. D 34. ~46* 47.例子: 23. 23/2=11…1, 11/2=5…1, 5/2=2…1, 2/2=1…0, 剩1. 即:10111,所以其八位无符号整数即为00010111.48.例子: 41. 41/2=20…1, 20/2=10…0, 10/2=5…0, 5/2=2…1, 2/2=1…0, 剩1. 即:101001,所以其16位无符号整数为0000000000101001.49. 例子:-101, 去其负号. 101/2=50…1, 50/2=25…0, 25/2=12…1,12/2=6…0, 6/2=3…0, 3/2=1…1, 剩1. 即:1100101. 其8位符号加绝对值即补足7位,再在最左边加1表负数. 即:11100101. 50. 同上.51. 例子:-110, 去其负号, 110/2=55…0, 55/2=27…1, 27/2=13…1,13/2=6…1, 6/2=3…0, 3/2=1…1, 剩1. 即:1101110. 其16位无符号整数位:0000000001101110,二进制反码整数即为:以下略.方法由上面依此类推.第四章位运算略第五章计算机组成39.A 40.B41.A 42.D 43.D 44.D 45.C 46.A 47.B 48.A 49.(2")50.D51.A 52.A 53.C 54.B 55.D 56.D 57.A 58.B 59.C 60.B61.B 62.A 63.C 64.B 65.D 66.C 67.D 68.D 69.C 70.C 71.A 72.C 73.B 74.C 75.B 76.A 77.C第六章计算机网络1.模型是标准化组织制定的用于网络设计的指南;协议是用于控制网络或交互式网络种不同设备间交互的一系列规那么。

计算机导论部分课后习题

计算机导论部分课后习题

第二章在计算机中如何表示小数点?什么是定点表示法和浮点表示法?设有一台浮点计算机,数码位为8位,阶码位为3位,则它所能表示数的范围是多少?什么是BCD码?什么是ASCII码?什么是汉字输入码、汉字内码、汉字字形码、汉字交换码和汉字地址码?它们各用于什么场合?汉字输入法:将汉字输入到电脑中,使用者可以根据自己的情况选择不同的输入方式。

汉字内码:是在计算机内部使用的汉字代码,汉字字型码:是确定一个汉字字形点阵的代码,是点阵的编码化形式汉字地址码:用来表示汉字字形信息在汉字中的地址什么是命题?在命题代数中主要的连接词有哪几种命题是一个具有具体意义的且能够判断真假的语句。

在命题代数中主要的连接有“与”;“或”;“非”;异或“;”条件“;和”双条件“等。

什么是命题公式?怎么判断两个命题公式等价?由命题变元,连接词和括号组成的合式的式子称为命题公式。

如果两个不同的命题公式P 和Q,无论命题变元取什么值它们的真值都相同,则该两个命题公式等价,记作P=Q。

计算机硬件系统由哪几部分组成?简述各部分的功能。

答:计算机硬件系统由运算器、控制器、输入设备和输出设备五个部分组成。

它们的作用如下:1运算器主要功能是算术运算和逻辑运算;2控制器功能是依次从存储器取出指令、翻译指令、分析指令,向其他部件发出控制信号,指挥计算机各部件协同工作;3存储器主要功能是存放程序和数据;4输入设备用来接收用户输入的数据和程序,并将它们转变为计算机可以识别的形式(二进制代码)存在内存中;5输出设备用于将存放在内存中由计算机处理的结果转变为人们所能接受的形式。

指令中操作码的功能是什么?简述指令的执行过程。

计算机的工作原理是什么?它是由谁首先提出来的?答:计算机在运行时,先从内存中取出第一条指令,通过控制器的译码,按指令的要求,从存贮器中取出数据进行指定的运算和逻辑操作等加工,然后再按地址把结果送到内存中去。

接下来,再取出第二条指令,在控制器的指挥下完成规定操作。

计算机科学导论(全英版)课后问答

计算机科学导论(全英版)课后问答

CHAPTER11.Explain the five parts of an information system .What part do people play inthis system?An information system has five parts: people, procedures, software, hardware and data.People: Are end users who use computer to make themselves more productive.Procedures: Specify rules or guidelines for computer operations.Software: Provides step-by-step instructions for computer hardware.Hardware: Processes the data to create information.Data: Consist of unprocessed facts including text, numbers, image and sounds.People are the most important part of any information system.2.What is system software? What kinds of programs are included in systemsoftware?System software helps the computer manage its own internal resources. It includes three kinds of programs: operating systems, utilities and device drivers programs.3.Define and compare basic and specialized application software. Describe somedifferent types of basic application software. Describe some types of specialized applications.Basic applications are the kinds of programs to be considered computer competent.Specialized applications are more narrowly focused on specific disciplines and occupations.Basic applications have some types, such as browser, word processor, spreadsheet ,and so on.Also specialized applications have many types, some of the best known are graphics, audio and video, multimedia, Web authoring ,and artificial intelligence programs.4.Describe the different types of computer. What is the most common type? Whatare the types of microcomputers?There are four types of computers: supercomputers, mainframe computers, minicomputers, and microcomputers.Supercomputers are the most powerful type of computer.Mainframe computers occupy specially wired, air-conditioned rooms, they are capable of great processing speeds and data storage.Minicomputers are refrigerator sized machines.Microcomputers are the least powerful, yet the most widely used and fastest-growing, type of computer.Microcomputers are the most common type of computers.There are four types of microcomputers: Desktop computers, Notebook computers, Handheld computers and PDA.5.What is connectivity? How are the wireless revolution and connectivityrelated? What is a computer network? What is the Internet? What is the Web?Connectivity is the capability of you microcomputer to share the information with other computers.Wireless revolution dramatically affect connectivity.A computer network is a communications system connecting two or more computers.Internet is the largest network in the world.The Web provides a multimedia interface to the numerous resources available on the Internet.CHAPTER21.Discuss the uses of the Internet. Which activities have you participated in?Which one do you think is the most popular?The most common uses of the Internet are the following: communicating, shopping, searching, entertainment, education, and so on. I have participated in almost all of them. I think communicating is the most popular.2.Explain the differences between the two most common types of providers.The two most common types of providers are National and wireless.National service providers provide access through standard telephone connections.Wireless service providers provide Internet connections for computers with wireless modems and a wide array of wireless devices.3.What are the basic elements of an message?A typical message has three basic elements: header, message and signature.4.What is social networking ? Describe the three types if social networkingsites.Social networking is the grouping of individuals into specific groups. Thereare three basic categories of social networking sites: reuniting, friend-of-a-friend and common interestReuniting sites are designed to connect people who have known one another but have lost touch.Friend-of-a-friend sites are designed to bring together two people who do not know one another but share a common friend.Common interest sites bring together individuals that share common interests or hobbies.5.Describe the different types of search engines. Given an example of the typeof search each engine is best for.There are three types of search engines: crawler-based search engines, metasearch engines and specialized search enginesCrawler-based search engines, such as Google, create their listings automatically.Metasearch engines are programs that automatically submit your search request to several engines simultaneously. The metasearch engines receives the results, eliminates duplicates, orders the hits, and then provides the edited list to you .one of the best known is Dogpile.Specialized search engines focus on subject-specific Web sites. such as Environment.CHAPTER31.Explain the difference between general-purpose and special-purposeapplications.General-purpose application are widely used in nearly every discipline and occupation. They include word processors, spreadsheets, database management systems and presentation graphics.Specialized application includes thousands of other programs that are more narrowly focused on specific disciplines and occupations.2.Discuss the common features of most software programs. Describe the newinterface to what-if analysis?Most applications use a GUI, use windows to display information, and have menus to present commands.3.What is the difference between a function and a formula? How is a formularelated to what-if analysis?A formula is an instruction to calculate or process. Functions are prewrittenformulas. A formula related to what-if analysis is called recalculation.4.What are presentation graphics programs? How are they used?Presentation graphics are programs that combine a variety of visual objects to create attractive, visually interesting presentation. People in a variety of setting and situations use presentation graphics programs to make their presentations more interesting and professional.5.What is the difference between an integrated package and a software suite?What are the advantages and disadvantages od each?An integrated package is a single program that provides the functionality ofa word processor, spreadsheet, database manager, and more. The primarydisadvantage of an integrated package is that the capabilities of each function are not as extensive as in the individual programs. The primary advantages are cost and simplicity.A software suite is a collection of separate application programs bundledtogether and sold as a group. It is significantly less expensive to buy a suite of applications than to buy each application separatelyCHAPTER41.Describe graphics , including desktop publishers, image editors, illustrationprograms, image galleries, and graphics suites.Graphics are widely used to analyze data and to create professional-looking presentations; Desktop publishers focus on page design and layout and provide greater flexibility; Image editors are programs for creating and editing bitmap images; Illustration programs are used to create and to edit vector images; Image galleries are libraries of electronic images. These images are used for a wide variety of applications from illustrating textbooks to providing visual interest to presentations;Graphics suites are some companies combining their separate graphics programs in groups.2.Discuss audio and video editing software.Audio editing software allows you to create and edit audio clips, most software allow you to add audio effects to your tracks. Video editingsoftware allows you to reorganize, add effects, and more to your digital video footage.3.What is multimedia? How are multimedia presentations developed?Multimedia is the integration of all sorts of media into one presentation.The creation of interactive multimedia presentations follows several steps: Plan, Design, Create and Support.4.Describe Web authoring , including Web site design and Web authoring programs.Creating a site is called Web authoring. A web site design is an interactive multimedia form of communication, designing a web site begins with determining the site’s overall content, the overall site design is commonly represented in a graphical map. More specialized and powerful programs, called Web authoring programs, are typically used to create sophisticated commercial sites.5.Discuss three areas of artificial intelligence.The three areas of artificial intelligence are virtual reality, knowledge-based systems and robotics. Virtual reality is an artificial, or simulated, reality generated in 3-D by a computer. Knowledge-based systems are a type of artificial intelligence that uses a database to provide assistance to users. Robotics is the field of study concerned with developing and using robots.CHAPTER51.Describe system software. What are the four types of system programs?System software works with end users, application software, and computer hardware to handle the majority of technical details. It consists of four types of programs: operating systems, utilities, device drivers and language translators.2.What are the basic functions of every operating system? What are the threebasic operating system categories?The basic functions of every operating system are : managing computer resources, providing a user interface, and running applications. The three basic operating system categories are: embedded, network and stand-alone.3.Explain the differences and similarities between Windows, Mac OS, and Linux.Windows is by far the most popular microcomputer operating system today. It comes in a variety of different versions and is designed to run with Intel and Intel-compatible microprocessors. Mac OS is not nearly as widely used as the Windows operating system. It is a powerful, easy-to-use operating system that is popular with professional graphic designs, desktop publishers, and many home users. While Windows, the Mac OS are proprietary operating systems, Linux is not. It is open source software free and available from many sources, including the Web.4.Discuss utilities. What are the five most essential utilities? What is autilities suite?Utilities are specialized programs designed to make computing easier. The five most essential utilities are: troubleshooting or diagnostic programs, antivirus programs, uninstall programs, backup programs and file compression programs. Utility suites combine several programs into one package.5.Explain the role of device drivers. Discuss the Add Printer Wizard andWindows Update.A device driver works with the operating system to allow communication betweenthe device and the rest of the computer system. Each time the computer system is started, the operating system loads all of the device drivers into memory.Whenever a new device is added to a computer system, a new device driver must be installed before the device can be used.Add Printer Wizard provides step-by-step guidance to select the appropriate printer driver and to install that driver. Windows uses Windows Update to make reinstalling or updating device drivers easily.CHAPTER61.Describe the four basic types of system units.There are four basic types of system units: Desktop system units, Notebook system units, Tablet PC system units, and Handheld computer system units.Desktop system units typically contain the system’s electronic components and selected secondary storage devices.Notebook system units are portable and much smaller. They contain the electronic components, selected secondary storage devices, and input device.Tablet PC system units are highly portable devices that support the use of a stylus or pen to input commands and data.Handheld computer system units are the smallest and are designed to fit into the palm of one hand.2.Describe the two basic components of the CPU.The two basic components are: the control unit and the arithmetic-logic unit.Control unit tells the rest of the computer system how to carry out a program’s instructions.Arithmetic-logic unit performs two types of operations---arithmetic and logical.3.What are the differences and similarities between the three types of memory?There are three types of memory chips: RAM, ROM, and CMOS.RAM chips hold the program and data that the CPU is presently processing, everything in most types of RAM is lost as soon as the microcomputer is turned off or a power failure.ROM chips have programs built into them at the factory. ROM chips are not volatile and cannot be changed by the user.CMOS chip provides flexibility and expandability for a computer system. It contains essential information that is required every time the computer system is turned on. It is powered by a battery and does not lose its contents when the power is turned. Its contents can be changed to reflect changes in the computer system.4.Identify five expansion cards and describe the function of each.Five expansion cards are: graphics cards, sound cards, modem cards, NIC and TV tuner cards.Graphics cards connect the system board to the computer’s monitor, they convert the internal electronic signals to video signals so they can be displayed on the monitor.Sound cards accept audio input from a microphone and convert it into a form that can be processed by the computer. They also convert internal electronic signals to audio signals.Modem cards allow distant computers to communicate with one another by converting electronic signals from within the system unit into electronic signals that can travel over telephone lines and other types of connections.NIC are used to connect a computer to one or more other computers.TV tuner cards can changes the TV signal into one that can be displayed on you monitor.5.Identify and describe four standard ports and two specialized ports.Four standard ports are: serial ports, parallel ports, universal serial bus ports and FireWire ports.Serial ports are often used to connect a mouse, keyboard, modem, and many other devices to the system unit.Parallel ports are used to connect external devices that need to send or receive a lot of data over a short distance.USB ports are gradually replacing serial and parallel ports.FireWire ports provide connections to specialized FireWire devices.CHAPTER71.Define input and output devices.Input is any data or instructions that are used by a computer. Input devices are hardware used to translate what people understand into a form that computers can process.2.Describe the three categories of output devices.①There are a widely of different pointing devices including the mouse,joystick, touch screen, light pen, and stylus.A mouse controls a pointer that is displayed on the monitor.A joystick is the most popular input device for computer games. You controlgame actions by varying the pressure, speed, and direction of the joystick.A touch screen is a particular kind of monitor with a clear plastic outerlayer.A light pen is a light-sensitive pen-like device.A stylus acts with the computer through handwriting recognition software.②There are three types of scanning devices: optical scanners, card readers,bar code readers, and character and mark recognition devices.An optical scanner accepts documents consisting of text and/or images and converts them to machine readable form.Card readers interpret encoded information.Bar code readers are either handheld wand readers or platform scanners.Character and mark recognition devices are scanners that are able to recognize special characters and marks.③Image capturing devices include digital cameras and digital video cameras.Digital cameras capture still images. Digital video cameras capture motion.④Audio input can take many forms including the human voice and music.Voice recognition systems accept voice commands to control computer operations and to create document.MIDI is a standard for connecting musical instruments to the system unit.3.Describe the three categories if output devices.The most widely used output devices are monitors, printers and audio output.Monitors present visual images of text and graphics.Printers translate information that has been processed by the system unit and present the information on paper.Audio output devices translate audio information from the computer into sounds that people can understand.4. Define output an output devices.Output is processed data or information. Output devices are hardware used to translate information that has been processed by the system unit into a form that humans can understands.5. What are combination input and output devices? Describe four such devices.Devices combine features of input devices such as scanners with features of output devices like printers are called combination input and output devices.Combination devices include fax machines, multifunction devices, Internet telephones, and terminals.A fax machine is a standard tool in nearly every office.Multifunction devices combine the capabilities of a scanner, printer, fax, and copying machine.Internet telephones are specialized input and output devices for receiving and sending voice communication.Terminals are input and output device that connect you to a mainframe or other type of computer.CHAPTER81.Discuss the traditional and high-capacity floppy disksThe traditional floppy disk is the 1.44MB 3-inch disk. They have a thin exterior jacket made of hard plastic to protect the flexible disk inside.The high capacity floppy disks are 3 inches in diameter. They are able to store more information, are thicker, and require special disk drives.2.What are the three types of hard disks? Describe three ways to improve harddisk performance.There are three types of hard disks: Internal hard disk, hard-disk cartridge, and hard-disk pack.Three ways to improve the performance of hard disks are disk caching, redundant arrays of inexpensive disks, and file compression/decompression.Disk caching improves hard-disk performance by anticipating data needs.Redundant arrays of inexpensive disks improve performance by expending external storage, improving access speed, and providing reliable storage.File compression and file decompression increase storage capacity by reducing the amount of space required to store data and programs.3.What are the two most common optical disc formats? What is hi def ? Describethe basic types for each format.The two most common optical disc formats are CD and DVD. Hi def is the next generation of optical discs.①There are four basic types of CDs: read only, write once, rewritable, andPicture and Photo CDs.Read only CDs cannot be written on or erased by the users, they are used to distribute large databases, references, and large software application packages.Write once CDs can be written to once, they are used to archive data and to record music download from the Internet.Rewritable CDs are similar to write once CDs except that the disks surface is not permanently altered when data is recorded.Picture and Photo CDs use a special format developed by Eastman Kodak to store digital images.②There are three types of DVDs: read only, write once, and rewriteable.Read only DVDs can provide over two hours of very high-quality video and sound comparable to that found in motion picture theatres.Write once DVDs are typically used to create permanent archives for large amounts of data and to record videos.Rewriteable DVDs are competing rewriteable formats.4.Discuss solid-state storage, Internet hard drives, and magnetic tape. Whatare the advantages and disadvantages of each?Solid-state storage does not have moving parts. Internet drives use the Internet to store data and information. Magnetic tape provides sequential access for backup.Solid-state storage is more expensive than the others, it is more reliable and requires less power.Internet drives are low cost and the flexibility to access information from any location using the Internet. Access speed is slower.Magnetic tapes provide slower sequential access. It is an effective and commonly used tool for backing up data.5. Discuss mass storage, enterprise storage system, and mass storage devices.Mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. Enterprise storage systems are the computer storage systems designed for large-scale, high-technology environments of the modern enterprises.Mass storage Devices have been described as mass storage include tape libraries, RAID systems, hard disk drives, magnetic tape drives, optical disc drives, magneto-optical disc drives, drum memory, floppy disk drives, punched tape and holographic memory.CHAPTER91.Define and discuss connectivity, the wireless revolution, and communications.①Connectivity is a concept related to using computer networks to link peopleand resources.②The single most dramatic change in connectivity and communications in thepast five years has been the widespread use of mobile or wireless telephones.This wireless technology allows individuals to stay connected with one another from almost anywhere at any time, the revolution is just beginning.③Communication systems transmit data from one location to another. Everycommunication system has four basic elements: sending and receiving devices, communication channel, connection devices, and data transmission specifications.2.Identify and describe the various physical and wireless communications.①Physical connections use a solid medium to connect sending and receivingdevices.These connections include telephone lines, coaxial cable, and fiber-optic cables.Telephone lines consist of twisted pair cable, they have been the standard transmission medium for years for both voice and data.Coaxial cable replaces the multiple wires of telephone lines with a single solid-copper core.Fiber-optic cable transmits data as pulses of light through tiny tubes of glass.②Wireless connections use the air to connect sending and receiving devices.Primary technologies used for wireless connections are infrared, broadcast radio, microwave, and satellite.Infrared uses infrared light waves to communicate over short distances.Broadcast radio communication uses special sending and receiving towers called transceivers.Microwave communication uses high-frequency radio waves.Satellite communication uses satellites orbiting about 22000 miles above the earth as microwave relay stations.3.Identify the standard Internet protocol and discuss its essential features.The standard protocol for the Internet is TCP/IP. The essential features of this protocol involve: identifying sending and receiving devices and reformatting information for transmission across the Internet.Identification: Every computer on the Internet has a unique number address called an IP address, the Internet uses IP addresses to deliver and to locate Web sites.Reformatting: Information sent or transmitted across the Internet usually travels through numerous interconnected networks. Before the massage is sent, it is reformatted or broken down into small parts called packets, at the receiving end, the packets are reassembled into the correct order.4.Define and discuss the four principal network topologies.The four principal network topologies are star, bus, ring, and hierarchical.In a star network, a number of small computers or peripheral devices are linked to a central unit, all communications pass through this central unit.In a bus network, each device in the network handles its own communication control.In a ring network, each device is connected to two other devices, forming a ring.The hierarchical network consists of several computers linked to a central host computer, other computers are also hosts to other, smaller computers or to peripheral devices.5.Define and discuss the three most common network strategies.The most common network strategies are terminal, client/server, and peer-to-peer systems.①In a terminal network system, processing power is centralized in one largecomputer. For the end user it is lack of control and flexibility.②Client/server network system use one computer to coordinate and supplyservices to other nodes on the network. One advantage of the client/sever network strategy is the ability to handle very large networks efficiently.Another advantage is the ability of powerful network management software to monitor and control network activities. The major disadvantages are the cost of installation and maintenance.③In a peer-to-peer network system, nodes have equal authority and can actas both clients and servers. The networks are inexpensive and easy to install, and they usually work well for smaller systems with fewer than 10 nodes.CHAPTER101.Discuss the impact of large database , private networks, the Internet, andthe Web on privacy.Large databases raise some serious concerns on privacy: identity theft and mistaken identity.The impact of private networks on privacy has the two parts: The first instance, of firms eavesdropping on employees, has inspired attempts at federal legislation. The second instance, in which online information services screen and reject messages, is a common activity with most commercial services.The internet brings illusion of anonymity, the web creates a history file, your web activity is monitored is by cookies. To respond to these privacy concerns, a code of fair information practice has been established.2.Discuss the carious kinds of computer criminals.Computer criminals are of five types:Employees: The largest category of computer criminals consists of those with the easiest access to computers-namely, employees.Outside users: Some suppliers or clients may have access to a company’s computer system.Hackers and crackers: Hackers are people who gain unauthorized access to a computer system for the fun and challenge of it. Crackers do the same thing but for malicious purposes.Organized crime: Members of organized crime groups have discovered that they can use computers just as people in legitimate businesses do, but for illegal purpose.Terrorists: Knowledgeable terrorist groups and hostile governments could potentially crash satellites and wage economic warfare by disrupting navigation and communication systems.3. What are the principal measures used to protect computer security? What isencryption? How is it used by corporations and individuals?Some of the principal measures to protect computer security are encryption, restricting access, anticipating disasters, and backing up data.Encryption is the conversion of data into a form, called a ciphertext that cannot be easily understood by unauthorized people.Corporations have use it for years that some law enforcement agencies are unable to wiretap messages from suspected criminals. Individuals are alsousing encryption programs to safeguard their private communications.4.What is ergonomics? How does computer use impact mental health? Physicalhealth?Ergonomics is defined as the study of human factors related to things people use.The physical health matters related to computers that have received the most attention recently are the following: eyestrain and headache, back and neck pain, and repetitive strain injury. Computer technology creates some irritants that may be counter productive: noise, and electronic monitoring.5.Describe the basic elements of the Green PC and what you can do to protectthe environment.The basic elements of the Green PC are: System unit, display, and manufacturing.As a computer user, you can do to help protect the environment are the following:conserve, recycle, and educate.。

计算机科学概论--问题与答案

计算机科学概论--问题与答案

e. 31
e. 11011 e. 5
8 e. 101.101
1.6 节
1. a. 3
b. 15
c. -4
d. -6
e. 0
f. -16
2. a. 00000110 b. 11111010
c. 11101111
d. 00001101 e. 11111111
f. 00000000
3. a. 11111111 b. 10101011
1.8 节
1. 行程长度编码、频率相关编码、相对编码和字典编码。 2. 121321112343535 3. 彩色卡通是由边框清晰的单色块构成的而且所包含的颜色数目是有限的。 4. 不是,GIF和JPEG都是有损压缩系统,也就是说,图像中的细节可能会丢失。 5. JPEG基准标准利用了人眼的一个事实:人眼对于颜色变化不如对光线的变化敏感。因此,
原因。
4. 最大的数值是 7 1 ,表示为位模式01111111。关于最小的正值,你们可以认为有2个“正确” 2
答案。首先,如果你坚持文中所描述的编码过程,它要求尾数的最高有效位必须为1(称为
规格化格式),答案则为 1 ,表示为位模式00001000。不过大多数机器并不对接近0的值施 32
加这样的限制,因此这时候的正确答案是 1 ,表示为位模式00000001。 256
2. 要写入的值、要写入的单元的地址以及要写入的命令。 3. 通用寄存器用于存储操作中马上用到的数据,主存储器用于存储不久就要用到的数据,海量
存储器用于存储暂时不会用到的数据。
2.2 节
问题与练习答案 417
1. move这个术语常用来表示从一个位置移到另外一个位置,因此后面留下一个空位。不过, 在一个机器中大多数情况下是不会发生这种移动的。相反,被移动的目标通常是被复制到新 的位置。

计算机导论--常见问题与回答

计算机导论--常见问题与回答

“计算机导论”常见问题与解答说明:在计算机导论的教学中,学生经常会问一些问题,课程组把比较常见的问题总结出来,并进行了简要的出回答,如下。

1、学习“计算机导论”的目的是什么?答:通过学习“计算机导论”课程,可以达到如下目的:了解计算机的发展简史,激发学习兴趣;掌握计算机的基本知识,建立专业知识体系框架;熟练掌握常用的计算机软件的使用,提高操作技能;了解计算机科学技术的最新发展,促进研究性学习;掌握计算机学科的思维方法,培养综合素质与创新能力。

这对于计算机专业学生四年的知识学习、能力提高、素质培养和日后的学术研究、技术开发、经营管理等工作具有十分重要的基础性和引导性作用。

由于“计算机导论”是学生进入大学后的第一门专业课程,该门课程不仅是让学生了解一些计算机专业的基本知识,还要对学生在学习方法、思维方式上进行引导,使学生尽快适应大学的学习方式,培养计算思维。

2、如何能够学好“计算机导论”?答:“计算机导论”课程的特点是:内容多、课时少、理论与实践并重,实际上后续的大多数专业课程也具有类似的特点。

需要学生做到四个认真:认真听讲、认真读书、认真思考、认真实践。

特别要注意认真读书和认真思考,这是大学生课后自主学习的主要方式,也是高中学习阶段比较欠缺的地方。

有些内容光靠听老师课堂上的讲授是不够的,必须要认真读书(甚至要多读几本书)、认真思考,才能真正理解所学内容,也才能真正变成自己的知识。

在高中阶段,所有的学习时间都由学校和老师安排,学生几乎没有自由支配的时间。

进入大学,自由支配的时间多了。

作为大学生,一定要充分利用自由时间,安排好自己的自主学习,要多看书、多思考、多实践。

3、“计算机导论”和后续专业课程有什么关系?答:从学知识角度看,“计算机导论”是后续主要专业课程内容的一个绪论,一个总体的概括性介绍。

其主要作用主要有两个:一是为后续专业课程的学习做一个知识上的铺垫,降低学习专业课程时的难度,使专业课程的学习效果更好。

《计算机科学导论》(第三版-)弗罗赞(翻译)

《计算机科学导论》(第三版-)弗罗赞(翻译)

Chapter 1 练习复习题1. 定义一个基于图灵模型的计算机。

答:Turing proposed that all kinds of computation could be performed by a special kind of a machine. He based the model on the actions that people perform when involved in computation. He abstracted these actions into a model for a computational machine that has really changed the world. 图灵模型假设各种各样的运算都能够通过一种特殊的机器来完成,图灵机的模型是基于各种运算过程的。

图灵模型把运算的过程从计算机器中分离开来,这确实改变了整个世界。

2. 定义一个基于冯•诺伊曼模型的计算机。

答:The von Neumann Model defines the components of a computer, which are memory, the arithmetic logic unit (ALU), the control unit and the input/output subsystems.冯•诺伊曼模型定义了计算机的组成,它包括存储器、算术逻辑单元、控制单元和输入/ 输出系统。

3. 在基于图灵模型的计算机中,程序的作用是什么?答:Based on the Turing model a program is a set of instruction that tells the computer what to do.基于图灵模型的计算机中程序是一系列的指令,这些指令告诉计算机怎样进行运算。

4. 在基于冯•诺伊曼模型的计算机中,程序的作用是什么?答:The von Neumann model states that the program must be stored in the memory. The memory of modern computers hosts both programs and their corresponding data. 冯•诺伊曼模型的计算机中,程序必须被保存在存储器中,存储程序模型的计算机包括了程序以及程序处理的数据。

计算机科学导论课后问答

计算机科学导论课后问答

1.Explain the five parts of an information system .What part do people play inthis system?An information system has five parts: people, procedures, software, hardware and data.People: Are end users who use computer to make themselves more productive.Procedures: Specify rules or guidelines for computer operations.Software: Provides step-by-step instructions for computer hardware.Hardware: Processes the data to create information.Data: Consist of unprocessed facts including text, numbers, image and sounds.People are the most important part of any information system.2.What is system software? What kinds of programs are included in system software?System software helps the computer manage its own internal resources. It includes three kinds of programs: operating systems, utilities and device drivers programs.3.Define and compare basic and specialized application software. Describe somedifferent types of basic application software. Describe some types of specialized applications.Basic applications are the kinds of programs to be considered computer competent.Specialized applications are more narrowly focused on specific disciplines and occupations.Basic applications have some types, such as browser, word processor, spreadsheet ,and so on.Also specialized applications have many types, some of the best known are graphics, audio and video, multimedia, Web authoring ,and artificial intelligence programs.4.Describe the different types of computer. What is the most common type? Whatare the types of microcomputers?There are four types of computers: supercomputers, mainframe computers, minicomputers, and microcomputers.Supercomputers are the most powerful type of computer.Mainframe computers occupy specially wired, air-conditioned rooms, they are capable of great processing speeds and data storage.Minicomputers are refrigerator sized machines.Microcomputers are the least powerful, yet the most widely used and fastest-growing, type of computer.Microcomputers are the most common type of computers.There are four types of microcomputers: Desktop computers, Notebook computers,Handheld computers and PDA.5.What is connectivity? How are the wireless revolution and connectivity related?What is a computer network? What is the Internet? What is the Web?Connectivity is the capability of you microcomputer to share the information with other computers.Wireless revolution dramatically affect connectivity.A computer network is a communications system connecting two or more computers.Internet is the largest network in the world.The Web provides a multimedia interface to the numerous resources available on the Internet.CHAPTER21.Discuss the uses of the Internet. Which activities have you participated in?Which one do you think is the most popular?The most common uses of the Internet are the following: communicating, shopping, searching, entertainment, education, and so on. I have participated in almost all of them. I think communicating is the most popular.2.Explain the differences between the two most common types of providers.The two most common types of providers are National and wireless.National service providers provide access through standard telephone connections. Wireless service providers provide Internet connections for computers with wireless modems and a wide array of wireless devices.3.What are the basic elements of an e-mail message?A typical e-mail message has three basic elements: header, message and signature.4.What is social networking ? Describe the three types if social networking sites.Social networking is the grouping of individuals into specific groups. There are three basic categories of social networking sites: reuniting, friend-of-a-friend and common interestReuniting sites are designed to connect people who have known one another but have lost touch.Friend-of-a-friend sites are designed to bring together two people who do not know one another but share a common friend.Common interest sites bring together individuals that share common interests orhobbies.5.Describe the different types of search engines. Given an example of the typeof search each engine is best for.There are three types of search engines: crawler-based search engines, metasearch engines and specialized search enginesCrawler-based search engines, such as Google, create their listings automatically.Metasearch engines are programs that automatically submit your search request to several engines simultaneously. The metasearch engines receives the results, eliminates duplicates, orders the hits, and then provides the edited list to you .one of the best known is Dogpile.Specialized search engines focus on subject-specific Web sites. such as Environment.CHAPTER31.Explain the difference between general-purpose and special-purposeapplications.General-purpose application are widely used in nearly every discipline and occupation. They include word processors, spreadsheets, database management systems and presentation graphics.Specialized application includes thousands of other programs that are more narrowly focused on specific disciplines and occupations.2.Discuss the common features of most software programs. Describe the newinterface to what-if analysis?Most applications use a GUI, use windows to display information, and have menus to present commands.3.What is the difference between a function and a formula? How is a formula relatedto what-if analysis?A formula is an instruction to calculate or process. Functions are prewrittenformulas. A formula related to what-if analysis is called recalculation.4.What are presentation graphics programs? How are they used?Presentation graphics are programs that combine a variety of visual objects to create attractive, visually interesting presentation. People in a variety of setting and situations use presentation graphics programs to make their presentations more interesting and professional.5.What is the difference between an integrated package and a software suite? Whatare the advantages and disadvantages od each?An integrated package is a single program that provides the functionality ofa word processor, spreadsheet, database manager, and more. The primarydisadvantage of an integrated package is that the capabilities of each function are not as extensive as in the individual programs. The primary advantages are cost and simplicity.A software suite is a collection of separate application programs bundledtogether and sold as a group. It is significantly less expensive to buy a suite of applications than to buy each application separatelyCHAPTER41.Describe graphics , including desktop publishers, image editors, illustrationprograms, image galleries, and graphics suites.Graphics are widely used to analyze data and to create professional-looking presentations; Desktop publishers focus on page design and layout and provide greater flexibility; Image editors are programs for creating and editing bitmap images; Illustration programs are used to create and to edit vector images; Image galleries are libraries of electronic images. These images are used for a wide variety of applications from illustrating textbooks to providing visual interest to presentations;Graphics suites are some companies combining their separate graphics programs in groups.2.Discuss audio and video editing software.Audio editing software allows you to create and edit audio clips, most software allow you to add audio effects to your tracks. Video editing software allows you to reorganize, add effects, and more to your digital video footage.3.What is multimedia? How are multimedia presentations developed?Multimedia is the integration of all sorts of media into one presentation. The creation of interactive multimedia presentations follows several steps: Plan, Design, Create and Support.4.Describe Web authoring , including Web site design and Web authoring programs.Creating a site is called Web authoring. A web site design is an interactive multimedia form of communication, designing a web site begins with determining the site’s overall content, the overall site design is commonly represented in a graphical map. More specialized and powerful programs, called Web authoring programs, are typically used to create sophisticated commercial sites.5.Discuss three areas of artificial intelligence.The three areas of artificial intelligence are virtual reality, knowledge-based systems and robotics. Virtual reality is an artificial, or simulated, reality generated in 3-D by a computer. Knowledge-based systems are a type of artificial intelligence that uses a database to provide assistance to users. Robotics is the field of study concerned with developing and using robots.CHAPTER51.Describe system software. What are the four types of system programs?System software works with end users, application software, and computer hardware to handle the majority of technical details. It consists of four types of programs: operating systems, utilities, device drivers and language translators.2.What are the basic functions of every operating system? What are the three basicoperating system categories?The basic functions of every operating system are : managing computer resources, providing a user interface, and running applications. The three basic operating system categories are: embedded, network and stand-alone.3.Explain the differences and similarities between Windows, Mac OS, and Linux.Windows is by far the most popular microcomputer operating system today. It comes in a variety of different versions and is designed to run with Intel and Intel-compatible microprocessors. Mac OS is not nearly as widely used as the Windows operating system. It is a powerful, easy-to-use operating system that is popular with professional graphic designs, desktop publishers, and many home users. While Windows, the Mac OS are proprietary operating systems, Linux is not. It is open source software free and available from many sources, including the Web.4.Discuss utilities. What are the five most essential utilities? What is autilities suite?Utilities are specialized programs designed to make computing easier. The five most essential utilities are: troubleshooting or diagnostic programs, antivirus programs, uninstall programs, backup programs and file compression programs.Utility suites combine several programs into one package.5.Explain the role of device drivers. Discuss the Add Printer Wizard and WindowsUpdate.A device driver works with the operating system to allow communication betweenthe device and the rest of the computer system. Each time the computer system is started, the operating system loads all of the device drivers into memory.Whenever a new device is added to a computer system, a new device driver must be installed before the device can be used.Add Printer Wizard provides step-by-step guidance to select the appropriate printer driver and to install that driver. Windows uses Windows Update to make reinstalling or updating device drivers easily.CHAPTER61.Describe the four basic types of system units.There are four basic types of system units: Desktop system units, Notebook system units, Tablet PC system units, and Handheld computer system units.Desktop system units typically contain the system’s electronic components and selected secondary storage devices.Notebook system units are portable and much smaller. They contain the electronic components, selected secondary storage devices, and input device.Tablet PC system units are highly portable devices that support the use of a stylus or pen to input commands and data.Handheld computer system units are the smallest and are designed to fit into the palm of one hand.2.Describe the two basic components of the CPU.The two basic components are: the control unit and the arithmetic-logic unit.Control unit tells the rest of the computer system how to carry out a program’s instructions.Arithmetic-logic unit performs two types of operations---arithmetic and logical.3.What are the differences and similarities between the three types of memory?There are three types of memory chips: RAM, ROM, and CMOS.RAM chips hold the program and data that the CPU is presently processing, everything in most types of RAM is lost as soon as the microcomputer is turned off or a power failure.ROM chips have programs built into them at the factory. ROM chips are not volatile and cannot be changed by the user.CMOS chip provides flexibility and expandability for a computer system. It contains essential information that is required every time the computer system is turned on. It is powered by a battery and does not lose its contents when the power is turned. Its contents can be changed to reflect changes in the computer system.4.Identify five expansion cards and describe the function of each.Five expansion cards are: graphics cards, sound cards, modem cards, NIC and TV tuner cards.Graphics cards connect the system board to the computer’s monitor, they convert the internal electronic signals to video signals so they can be displayed on the monitor.Sound cards accept audio input from a microphone and convert it into a form that can be processed by the computer. They also convert internal electronic signals to audio signals.Modem cards allow distant computers to communicate with one another by converting electronic signals from within the system unit into electronic signals that can travel over telephone lines and other types of connections.NIC are used to connect a computer to one or more other computers.TV tuner cards can changes the TV signal into one that can be displayed on you monitor.5.Identify and describe four standard ports and two specialized ports.Four standard ports are: serial ports, parallel ports, universal serial bus ports and FireWire ports.Serial ports are often used to connect a mouse, keyboard, modem, and many other devices to the system unit.Parallel ports are used to connect external devices that need to send or receivea lot of data over a short distance.USB ports are gradually replacing serial and parallel ports.FireWire ports provide connections to specialized FireWire devices.CHAPTER71.Define input and output devices.Input is any data or instructions that are used by a computer. Input devices are hardware used to translate what people understand into a form that computers can process.2.Describe the three categories of output devices.①There are a widely of different pointing devices including the mouse, joystick,touch screen, light pen, and stylus.A mouse controls a pointer that is displayed on the monitor.A joystick is the most popular input device for computer games. You control gameactions by varying the pressure, speed, and direction of the joystick.A touch screen is a particular kind of monitor with a clear plastic outer layer.A light pen is a light-sensitive pen-like device.A stylus acts with the computer through handwriting recognition software.②There are three types of scanning devices: optical scanners, card readers, barcode readers, and character and mark recognition devices.An optical scanner accepts documents consisting of text and/or images and converts them to machine readable form.Card readers interpret encoded information.Bar code readers are either handheld wand readers or platform scanners.Character and mark recognition devices are scanners that are able to recognize special characters and marks.③Image capturing devices include digital cameras and digital video cameras.Digital cameras capture still images. Digital video cameras capture motion.④Audio input can take many forms including the human voice and music.Voice recognition systems accept voice commands to control computer operations and to create document.MIDI is a standard for connecting musical instruments to the system unit.3.Describe the three categories if output devices.The most widely used output devices are monitors, printers and audio output.Monitors present visual images of text and graphics.Printers translate information that has been processed by the system unit and present the information on paper.Audio output devices translate audio information from the computer into sounds that people can understand.4. Define output an output devices.Output is processed data or information. Output devices are hardware used to translate information that has been processed by the system unit into a form that humans can understands.5. What are combination input and output devices? Describe four such devices.Devices combine features of input devices such as scanners with features of output devices like printers are called combination input and output devices.Combination devices include fax machines, multifunction devices, Internet telephones, and terminals.A fax machine is a standard tool in nearly every office.Multifunction devices combine the capabilities of a scanner, printer, fax, and copying machine.Internet telephones are specialized input and output devices for receiving and sending voice communication.Terminals are input and output device that connect you to a mainframe or other type of computer.CHAPTER81.Discuss the traditional and high-capacity floppy disksThe traditional floppy disk is the 3-inch disk. They have a thin exterior jacket made of hard plastic to protect the flexible disk inside.The high capacity floppy disks are 3 inches in diameter. They are able to store more information, are thicker, and require special disk drives.2.What are the three types of hard disks? Describe three ways to improve hard diskperformance.There are three types of hard disks: Internal hard disk, hard-disk cartridge, and hard-disk pack.Three ways to improve the performance of hard disks are disk caching, redundant arrays of inexpensive disks, and file compression/decompression.Disk caching improves hard-disk performance by anticipating data needs.Redundant arrays of inexpensive disks improve performance by expending external storage, improving access speed, and providing reliable storage.File compression and file decompression increase storage capacity by reducing the amount of space required to store data and programs.3.What are the two most common optical disc formats? What is hi def ? Describethe basic types for each format.The two most common optical disc formats are CD and DVD. Hi def is the nextgeneration of optical discs.①There are four basic types of CDs: read only, write once, rewritable, andPicture and Photo CDs.Read only CDs cannot be written on or erased by the users, they are used to distribute large databases, references, and large software application packages.Write once CDs can be written to once, they are used to archive data and to record music download from the Internet.Rewritable CDs are similar to write once CDs except that the disks surface is not permanently altered when data is recorded.Picture and Photo CDs use a special format developed by Eastman Kodak to store digital images.②There are three types of DVDs: read only, write once, and rewriteable.Read only DVDs can provide over two hours of very high-quality video and sound comparable to that found in motion picture theatres.Write once DVDs are typically used to create permanent archives for large amounts of data and to record videos.Rewriteable DVDs are competing rewriteable formats.4.Discuss solid-state storage, Internet hard drives, and magnetic tape. What arethe advantages and disadvantages of each?Solid-state storage does not have moving parts. Internet drives use the Internet to store data and information. Magnetic tape provides sequential access for backup.Solid-state storage is more expensive than the others, it is more reliable and requires less power.Internet drives are low cost and the flexibility to access information from any location using the Internet. Access speed is slower.Magnetic tapes provide slower sequential access. It is an effective and commonly used tool for backing up data.5. Discuss mass storage, enterprise storage system, and mass storage devices.Mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. Enterprise storage systems are the computer storage systems designed for large-scale, high-technology environments of the modern storage Devices have been described as mass storage include tape libraries, RAID systems, hard disk drives, magnetic tape drives, optical disc drives, magneto-optical disc drives, drum memory, floppy disk drives, punched tape and holographic memory.CHAPTER91.Define and discuss connectivity, the wireless revolution, and communications.①Connectivity is a concept related to using computer networks to link peopleand resources.②The single most dramatic change in connectivity and communications in the pastfive years has been the widespread use of mobile or wireless telephones. This wireless technology allows individuals to stay connected with one another from almost anywhere at any time, the revolution is just beginning.③Communication systems transmit data from one location to another. Everycommunication system has four basic elements: sending and receiving devices, communication channel, connection devices, and data transmission specifications.2.Identify and describe the various physical and wireless communications.①Physical connections use a solid medium to connect sending and receivingdevices.These connections include telephone lines, coaxial cable, and fiber-optic cables.Telephone lines consist of twisted pair cable, they have been the standard transmission medium for years for both voice and data.Coaxial cable replaces the multiple wires of telephone lines with a single solid-copper core.Fiber-optic cable transmits data as pulses of light through tiny tubes of glass.②Wireless connections use the air to connect sending and receiving devices.Primary technologies used for wireless connections are infrared, broadcast radio, microwave, and satellite.Infrared uses infrared light waves to communicate over short distances.Broadcast radio communication uses special sending and receiving towers called transceivers.Microwave communication uses high-frequency radio waves.Satellite communication uses satellites orbiting about 22000 miles above the earth as microwave relay stations.3.Identify the standard Internet protocol and discuss its essential features.The standard protocol for the Internet is TCP/IP. The essential features of this protocol involve: identifying sending and receiving devices and reformatting information for transmission across the Internet.Identification: Every computer on the Internet has a unique number address called an IP address, the Internet uses IP addresses to deliver e-mail and to locateWeb sites.Reformatting: Information sent or transmitted across the Internet usually travels through numerous interconnected networks. Before the massage is sent, it is reformatted or broken down into small parts called packets, at the receiving end, the packets are reassembled into the correct order.4.Define and discuss the four principal network topologies.The four principal network topologies are star, bus, ring, and hierarchical.In a star network, a number of small computers or peripheral devices are linked to a central unit, all communications pass through this central unit.In a bus network, each device in the network handles its own communication control.In a ring network, each device is connected to two other devices, forming a ring.The hierarchical network consists of several computers linked to a central host computer, other computers are also hosts to other, smaller computers or to peripheral devices.5.Define and discuss the three most common network strategies.The most common network strategies are terminal, client/server, and peer-to-peer systems.①In a terminal network system, processing power is centralized in one largecomputer. For the end user it is lack of control and flexibility.②Client/server network system use one computer to coordinate and supplyservices to other nodes on the network. One advantage of the client/sever network strategy is the ability to handle very large networks efficiently. Another advantage is the ability of powerful network management software to monitor and control network activities. The major disadvantages are the cost of installation and maintenance.③In a peer-to-peer network system, nodes have equal authority and can act asboth clients and servers. The networks are inexpensive and easy to install, and they usually work well for smaller systems with fewer than 10 nodes.CHAPTER101.Discuss the impact of large database , private networks, the Internet, and theWeb on privacy.Large databases raise some serious concerns on privacy: identity theft and mistaken identity.The impact of private networks on privacy has the two parts: The first instance, of firms eavesdropping on employees, has inspired attempts at federallegislation. The second instance, in which online information services screen and reject messages, is a common activity with most commercial services.The internet brings illusion of anonymity, the web creates a history file, your web activity is monitored is by cookies. To respond to these privacy concerns,a code of fair information practice has been established.2.Discuss the carious kinds of computer criminals.Computer criminals are of five types:Employees: The largest category of computer criminals consists of those with the easiest access to computers-namely, employees.Outside users: Some suppliers or clients may have access to a company’s computer system.Hackers and crackers: Hackers are people who gain unauthorized access to a computer system for the fun and challenge of it. Crackers do the same thing but for malicious purposes.Organized crime: Members of organized crime groups have discovered that they can use computers just as people in legitimate businesses do, but for illegal purpose.Terrorists: Knowledgeable terrorist groups and hostile governments could potentially crash satellites and wage economic warfare by disrupting navigation and communication systems.3. What are the principal measures used to protect computer security? What isencryption? How is it used by corporations and individuals?Some of the principal measures to protect computer security are encryption, restricting access, anticipating disasters, and backing up data.Encryption is the conversion of data into a form, called a ciphertext that cannot be easily understood by unauthorized people.Corporations have use it for years that some law enforcement agencies are unable to wiretap messages from suspected criminals. Individuals are also using encryption programs to safeguard their private communications.4.What is ergonomics? How does computer use impact mental health? Physical health?Ergonomics is defined as the study of human factors related to things people use.The physical health matters related to computers that have received the most attention recently are the following: eyestrain and headache, back and neck pain, and repetitive strain injury. Computer technology creates some irritants that may be counter productive: noise, and electronic monitoring.5.Describe the basic elements of the Green PC and what you can do to protect the。

计算机科学与导论课后习题答案 第6章 程序设计与算法分析

计算机科学与导论课后习题答案  第6章  程序设计与算法分析
(3) 问题的边界应该清晰明确。只有这样才能精确地解决这些子问题,否则就会模棱两可,无从下手。
5.简述面向对象和结构化程序设计的区别。
答:面向对象是从本质上区别于传统的结构化方法的一种新方法、新思路。它吸收了结构化程序设计的全部优点,同时又考虑到现实世界与计算机之间的关系,认为现实世界是由一系列彼此相关并且能够相互通信的实体组成,这些实体就是面向对象方法中的对象,每个对象都有自己的自然属性和行为特征,而一类相似对象的共性的抽象描述,就是面向对象方法中的核心——类。
9.用图示法表示语言处理的过程。
答:语言处理的过程如图所示:
10.简述编译程序的概念。
编译程序是把高级语言程序(源程序)作为一个整体来处理,在应用源程序执行之前,就将程序源代码“翻译”成目标代码(机器语言),编译后与系统提供的代码库链接,形成—个完整的可执行的机器语言程序(目标程序代码)。
第6章 程序设计与算法分析
习题(答案)
一、选择题
1. A 2. D 3. A 4. C 5. D
6. B 7. B 8. D 9. ABCD 10. D
11. C 12. A 13. B 14. D 15. A
二、简答题
1.简述程序的概念。
答:一个程序就是能够实现特定功能的一组指令序列的集合。或者表示为:程序=算法+数据结构。
答:语法分析是编译过程的第二个阶段,任务是在词法分析的基础上将单词序列分解成各类语法短语,如“程序”、“语句”、“表达式”等等。
14.简述语义处理的功能。
答:编译过程中的语义处理实现两个功能:
(1) 审查每个语法结构的静态语义,即验证语法结构合法的程序是否真正有意义,有时把这个工作称为静态语义分析或静态审查。

计算机科学导论 (全英版)课后问答

计算机科学导论 (全英版)课后问答

CHAPTER11.Explain the five parts of an information system 。

What part do people play in thissystem?An information system has five parts: people,procedures, software,hardware and data.People:Are end users who use computer to make themselves more productive.Procedures:Specify rules or guidelines for computer operations.Software:Provides step-by—step instructions for computer hardware.Hardware: Processes the data to create information.Data: Consist of unprocessed facts including text, numbers, image and sounds。

People are the most important part of any information system.2.What is system software? What kinds of programs are included in system software?System software helps the computer manage its own internal resources. It includes three kinds of programs: operating systems,utilities and device drivers programs。

计算机科学导论(本)第一章习题答案

计算机科学导论(本)第一章习题答案

计算机科学导论(本)第一章习题答案1. 什么是计算机科学?计算机科学是研究计算机原理、功能、性能和实现,并解决与计算机相关的问题的学科。

2. 计算机科学的发展历史有哪些重要阶段?计算机科学的发展历史可以分为以下几个重要阶段:- 1940年代至1950年代:电子管计算机时代。

研制了世界上第一台通用电子计算机ENIAC。

- 1950年代至1960年代:晶体管计算机时代。

发明了晶体管,使得计算机更加小型化和可靠。

- 1960年代至1970年代:集成电路计算机时代。

发明了集成电路,提高了计算机的性能和可靠性。

- 1970年代至1980年代:微处理器计算机时代。

发明了微处理器,使得个人计算机普及起来。

- 1990年代至今:互联网和移动计算时代。

互联网的兴起和移动计算设备的发展改变了人们的生活方式。

3. 计算机科学包括哪些主要研究领域?计算机科学包括以下主要研究领域:- 算法与数据结构:研究解决问题的方法和数据的组织方式。

- 编程语言与编译技术:研究编程语言的设计和实现方法。

- 操作系统:研究管理计算机硬件和软件资源的系统。

- 数据库与信息管理:研究数据的存储、检索和管理方法。

- 人工智能与机器研究:研究使计算机具备智能的方法和算法。

- 计算机网络与通信:研究计算机之间的通信和网络技术。

- 图形与图像处理:研究图形和图像的生成、处理和分析方法。

4. 什么是编程语言?编程语言是一种用于编写计算机程序的形式语言。

它定义了程序的结构、语法和语义,用于指导计算机执行特定的操作。

5. 编程语言的分类有哪些?编程语言可以根据不同的特性进行分类,主要有以下几种分类方法:- 低级语言和高级语言:低级语言直接操作计算机硬件,高级语言更加抽象。

- 编译型语言和解释型语言:编译型语言在程序执行之前将代码转换为机器语言,解释型语言逐行解释执行。

- 过程式语言和面向对象语言:过程式语言以过程为基本单位,面向对象语言以对象为基本单位。

计算机科学导论课本答案(完整版)

计算机科学导论课本答案(完整版)

第1章概述习题(答案)一.选择题1. D2. B3. CD4. C5. ABC6. A7. B8. B9. ABCD 10. ABCDE二.简答题1.什么是计算机系统?计算机系统是一种能够按照事先存储的程序,自动、高速地对数据进行输入、处理、输出和存储的系统,由计算机硬件系统和计算机软件系统两大部分组成。

2.请解释冯•诺依曼所提出的“存储程序”概念。

把程序和数据都以二进制的形式统一存放在存储器中,由机器自动执行。

不同的程序解决不同的问题,实现了计算机通用计算的功能。

3.控制器的主要功能是什么?控制器基本功能就是从内存中取出指令和执行指令,即控制器按程序计数器指出的指令地址从内存中取出该指令进行译码,然后根据该指令功能向有关部件发出控制命令,执行该指令。

另外,控制器在工作过程中,还要接受各部件反馈回来的信息。

4.简述CPU和主机的概念。

通常把运算器、控制器做在一个大规模集成电路块上称为中央处理器,又称CPU(Central Processing Unit)。

通常把内存储器、运算器和控制器合称为计算机主机,也可以说主机是由CPU与内存储器组成的,而主机以外的装置称为外部设备,外部设备包括输入/输出设备,外存储器等。

5.什么是计算机软件?计算机软件的分类有哪些?软件是指用来指挥计算机运行的各种程序的总和以及开发、使用和维护这些程序所需的技术文档。

计算机软件系统分为系统软件和应用软件。

计算机系统软件由操作系统、语言处理系统、以及各种软件工具等组成,指挥、控制计算机硬件系统按照预定的程序运行、工作,从而达到预定的目标。

应用软件是用户利用计算机软、硬件资源为解决各类应用问题而编写的软件,包括用户程序及其说明性文件资料。

6.计算机有哪些主要的特点?(1)运算速度快、精度高计算机的字长越长,其精度越高,现在世界上最快的计算机每秒可以运算几十万亿次以上。

一般计算机可以有十几位甚至几十位(二进制)有效数字,计算精度可由千分之几到百万分之几,是任何计算工具所望尘莫及的。

计算机科学导论课后习题答案-第三章

计算机科学导论课后习题答案-第三章

数据存储After reading this chapter, the reader should be able to :了解计算机内部不同类型数据的不同表示方法理解整数的不同编码表示形式理解浮点数3.2存储数字3.2.1INTEGERREPRESENTATION INTEGER:整数无符号整数格式---没有符号的整数,它的范围介于0到正无穷之间。

范围:0~(2N-1)无符号整数的表示范围# of Bits ---------816Range-------------------------------------0 ~ 255 0 ~ 65,535表示法:(1)首先将整数变成二进制数;(2)如果二进制位数不足N位,则在二进制数的左边补0,使它的总位数为N位。

Example 3.1将7存储在8位存储单元中。

Solution首先将数据转换为二进制---111。

在高位加5个0让数据变成8位---00000111。

最后将数据存入存储单元。

Example 3.2将285存储在16位存储单元中。

00000001 00011110无符号整数的存储示例:在8位机和16位机中Decimal ------------7234258 24,760 1,245,6788-bit allocation------------0000011111101010overflowoverflowoverflow16-bit allocation------------------------------0000000000000111000000001110101000000001000000100110000010111000overflow译解(计算机如何读取并输出无符号整数):将N位二进制数从二制数系统转换到十进制系统。

Example内存中的无符号整数位串00101011 在输出设备上将显示为什么?43应用:(1)计数;(2)寻址。

计算机科学导论课后习题答案-第二章

计算机科学导论课后习题答案-第二章

数字系统2.1DATA TYPES不同类型的数据数据在计算机中,数据是使用二进制系统来表示的。

在这种系统中,位模式(一系列的0和1)被用来表示数。

代码不同的位模式集合被设计用于表示文本符号,每一个集合被称为代码。

表示符号的过程----编码。

编码与解码的例子2.2DATA INSIDETHE COMPUTER位(bit)----是存储在计算机中的最小数据单位;它是0或1。

字节Byte----通常长度为8的位模式被称为一个字节。

预备知识22=4 24=16 28=256 210=10241K= 210=1024 (Kilo)1M=1024K= 220(Mega)1G=1024M= 230 (Giga)1个二进制位:bit(比特)8个二进制位:Byte(字节)1Byte=8bit2个字节:Word(字)1Word=2Byte=16bit数制▪十进制:基数为10,逢十进一12.34 = 1×101 + 2 ×100 + 3 ×10-1 + 4 ×10-2▪二进制:基数为2,逢二进一11012 = 1 ×23 + 1 ×22 + 1 ×20 = 1310▪十六进制:基数为16,逢十六进一1001, 0001, 1000, 01115 1 8 7= 5 ×163+ 1 ×162+ 8 ×161+ 7 ×160▪八进制:基数为8,逢八进一数制之间的转换▪二进制↔十进制→1011B=11D←降幂法除法例:27D= ? B27 11 3 3 1-↓-↓-↓-↓-↓16 8 4 2 11 1 0 1 1∴27D=11011B▪二进制↔十六进制→0011 0101 1011 1111↓↓↓↓3 5 B F∴0011010110111111B=35BFH← A 1 9 C↓↓↓↓1010 0001 1001 1100∴A19CH=1010000110011100B▪十六进制↔十进制→BF3CH=11⨯163 + 15⨯162 + 3⨯161 + 12⨯160←降幂法除法例:399D= ? H399 143 15-↓-↓-↓256 16 1⨯⨯⨯1 8 F∴399D=18FH2.3REPRESENTINGDATA黑-白图像的位图图形表示方法彩色像素的表示方法矢量图—将图像分解成曲线和直线的组合,其中每一曲线或直线同数学公式表示。

计算机导论双语试题及答案

计算机导论双语试题及答案

计算机导论双语试题及答案(题目)(正文)Part I(选择题)请在每道题后方括号内写出你认为正确的选项。

1. 计算机科学的定义是什么?A. 研究计算机硬件的科学。

B. 研究计算机软件的科学。

C. 研究计算机及其应用的科学。

[C]2. 计算机硬件主要包括以下哪些组成部分?A. CPU和内存。

B. 操作系统和应用软件。

C. 输入设备和输出设备。

[C]3. 下列哪个是计算机二进制系统中使用的数字?A. 十进制。

B. 二进制。

[B]C. 八进制。

4. 哪种编程语言是计算机与人类交互的桥梁?A. 机器语言。

B. 汇编语言。

C. 高级语言。

[C]5. 下列哪种计算机网络覆盖范围最广?A. 局域网。

B. 城域网。

C. 互联网。

[C]Part II(问答题)请用英文回答以下问题。

1. What is the difference between hardware and software?Hardware refers to the physical components of a computer system, such as the CPU and memory, while software refers to the programs and data used by the computer.2. What is the binary system in computing?The binary system is a number system that uses only two digits, 0 and 1, to represent all numeric values and data in a computer.3. What is the role of an operating system in a computer?The operating system acts as an intermediary between the user and the computer hardware, managing the resources and providing a user-friendly interface for interacting with the computer.4. What is the significance of computer networks?Computer networks allow computers to communicate and share resources, enabling the exchange of information and facilitating collaboration on a global scale.5. What is programming language?A programming language is a set of instructions and rules used to write computer programs, allowing humans to communicate their instructions to the computer.Part III(编程题)请用您熟悉的编程语言完成以下任务。

计算机科学导论 (全英版)课后问答-推荐下载

计算机科学导论 (全英版)课后问答-推荐下载

CHAPTER11.Explain the five parts of an information system .What part do people play in this system?An information system has five parts: people, procedures, software, hardware and data.People: Are end users who use computer to make themselves more productive.Procedures: Specify rules or guidelines for computer operations.Software: Provides step-by-step instructions for computer hardware.Hardware: Processes the data to create information.Data: Consist of unprocessed facts including text, numbers, image and sounds.People are the most important part of any information system.2.What is system software? What kinds of programs are included in system software?System software helps the computer manage its own internal resources. It includes three kinds of programs: operating systems, utilities and device drivers programs.3.Define and compare basic and specialized application software. Describe some differenttypes of basic application software. Describe some types of specialized applications.Basic applications are the kinds of programs to be considered computer competent.Specialized applications are more narrowly focused on specific disciplines and occupations.Basic applications have some types, such as browser, word processor, spreadsheet ,and so on.Also specialized applications have many types, some of the best known are graphics, audio and video, multimedia, Web authoring ,and artificial intelligence programs.4.Describe the different types of computer. What is the most common type? What are thetypes of microcomputers?There are four types of computers: supercomputers, mainframe computers, minicomputers, and microcomputers.Supercomputers are the most powerful type of computer.Mainframe computers occupy specially wired, air-conditioned rooms, they are capable of great processing speeds and data storage.Minicomputers are refrigerator sized machines.Microcomputers are the least powerful, yet the most widely used and fastest-growing, type of computer.Microcomputers are the most common type of computers.There are four types of microcomputers: Desktop computers, Notebook computers, Handheld computers and PDA.5.What is connectivity? How are the wireless revolution and connectivity related? What isa computer network? What is the Internet? What is the Web?Connectivity is the capability of you microcomputer to share the information with other computers.Wireless revolution dramatically affect connectivity.A computer network is a communications system connecting two or more computers.Internet is the largest network in the world.The Web provides a multimedia interface to the numerous resources available on the Internet.CHAPTER21.Discuss the uses of the Internet. Which activities have you participated in? Which one doyou think is the most popular?The most common uses of the Internet are the following: communicating, shopping, searching, entertainment, education, and so on. I have participated in almost all of them. I think communicating is the most popular.2.Explain the differences between the two most common types of providers.The two most common types of providers are National and wireless.National service providers provide access through standard telephone connections.Wireless service providers provide Internet connections for computers with wireless modems and a wide array of wireless devices.3.What are the basic elements of an e-mail message?A typical e-mail message has three basic elements: header, message and signature.4.What is social networking ? Describe the three types if social networking sites.Social networking is the grouping of individuals into specific groups. There are three basic categories of social networking sites: reuniting, friend-of-a-friend and common interest Reuniting sites are designed to connect people who have known one another but have lost touch. Friend-of-a-friend sites are designed to bring together two people who do not know one another but share a common friend.Common interest sites bring together individuals that share common interests or hobbies.5.Describe the different types of search engines. Given an example of the type of search eachengine is best for.There are three types of search engines: crawler-based search engines, metasearch engines and specialized search enginesCrawler-based search engines, such as Google, create their listings automatically.Metasearch engines are programs that automatically submit your search request to several engines simultaneously. The metasearch engines receives the results, eliminates duplicates, orders the hits, and then provides the edited list to you .one of the best known is Dogpile.Specialized search engines focus on subject-specific Web sites. such as Environment.CHAPTER31.Explain the difference between general-purpose and special-purpose applications.General-purpose application are widely used in nearly every discipline and occupation. They include word processors, spreadsheets, database management systems and presentation graphics.Specialized application includes thousands of other programs that are more narrowly focused on specific disciplines and occupations.2.Discuss the common features of most software programs. Describe the new interface towhat-if analysis?Most applications use a GUI, use windows to display information, and have menus to present commands.3.What is the difference between a function and a formula? How is a formula related towhat-if analysis?A formula is an instruction to calculate or process. Functions are prewritten formulas. A formularelated to what-if analysis is called recalculation.4.What are presentation graphics programs? How are they used?Presentation graphics are programs that combine a variety of visual objects to create attractive, visually interesting presentation. People in a variety of setting and situations use presentation graphics programs to make their presentations more interesting and professional.5.What is the difference between an integrated package and a software suite? What are theadvantages and disadvantages od each?An integrated package is a single program that provides the functionality of a word processor, spreadsheet, database manager, and more. The primary disadvantage of an integrated package is that the capabilities of each function are not as extensive as in the individual programs. The primary advantages are cost and simplicity.A software suite is a collection of separate application programs bundled together and sold as agroup. It is significantly less expensive to buy a suite of applications than to buy eachapplication separatelyCHAPTER41.Describe graphics , including desktop publishers, image editors, illustration programs,image galleries, and graphics suites.Graphics are widely used to analyze data and to create professional-looking presentations;Desktop publishers focus on page design and layout and provide greater flexibility;Image editors are programs for creating and editing bitmap images; Illustration programs are used to create and to edit vector images; Image galleries are libraries of electronic images. These images are used for a wide variety of applications from illustrating textbooks to providing visual interest to presentations;Graphics suites are some companies combining their separate graphics programs in groups.2.Discuss audio and video editing software.Audio editing software allows you to create and edit audio clips, most software allow you to add audio effects to your tracks. Video editing software allows you to reorganize, add effects, and more to your digital video footage.3.What is multimedia? How are multimedia presentations developed?Multimedia is the integration of all sorts of media into one presentation. The creation of interactive multimedia presentations follows several steps: Plan, Design, Create and Support.4.Describe Web authoring , including Web site design and Web authoring programs.Creating a site is called Web authoring. A web site design is an interactive multimedia form of communication, designing a web site begins with determining the site’s overall content, the overall site design is commonly represented in a graphical map. More specialized and powerful programs, called Web authoring programs, are typically used to create sophisticated commercial sites.5.Discuss three areas of artificial intelligence.The three areas of artificial intelligence are virtual reality, knowledge-based systems and robotics. Virtual reality is an artificial, or simulated, reality generated in 3-D by a computer.Knowledge-based systems are a type of artificial intelligence that uses a database to provide assistance to users. Robotics is the field of study concerned with developing and using robots.1.Describe system software. What are the four types of system programs?System software works with end users, application software, and computer hardware to handle the majority of technical details. It consists of four types of programs: operating systems, utilities, device drivers and language translators.2.What are the basic functions of every operating system? What are the three basicoperating system categories?The basic functions of every operating system are : managing computer resources, providing a user interface, and running applications. The three basic operating system categories are: embedded, network and stand-alone.3.Explain the differences and similarities between Windows, Mac OS, and Linux.Windows is by far the most popular microcomputer operating system today. It comes in a variety of different versions and is designed to run with Intel and Intel-compatible microprocessors. Mac OS is not nearly as widely used as the Windows operating system. It isa powerful, easy-to-use operating system that is popular with professional graphic designs,desktop publishers, and many home users. While Windows, the Mac OS are proprietary operating systems, Linux is not. It is open source software free and available from many sources, including the Web.4.Discuss utilities. What are the five most essential utilities? What is a utilities suite?Utilities are specialized programs designed to make computing easier. The five most essential utilities are: troubleshooting or diagnostic programs, antivirus programs, uninstall programs, backup programs and file compression programs. Utility suites combine several programs into one package.5.Explain the role of device drivers. Discuss the Add Printer Wizard and Windows Update.A device driver works with the operating system to allow communication between the deviceand the rest of the computer system. Each time the computer system is started, the operating system loads all of the device drivers into memory. Whenever a new device is added to a computer system, a new device driver must be installed before the device can be used.Add Printer Wizard provides step-by-step guidance to select the appropriate printer driver and to install that driver. Windows uses Windows Update to make reinstalling or updating device drivers easily.1.Describe the four basic types of system units.There are four basic types of system units: Desktop system units, Notebook system units, Tablet PC system units, and Handheld computer system units.Desktop system units typically contain the system’s electronic components and selected secondary storage devices.Notebook system units are portable and much smaller. They contain the electronic components, selected secondary storage devices, and input device.Tablet PC system units are highly portable devices that support the use of a stylus or pen to input commands and data.Handheld computer system units are the smallest and are designed to fit into the palm of one hand.2.Describe the two basic components of the CPU.The two basic components are: the control unit and the arithmetic-logic unit.Control unit tells the rest of the computer system how to carry out a program’s instructions.Arithmetic-logic unit performs two types of operations---arithmetic and logical.3.What are the differences and similarities between the three types of memory?There are three types of memory chips: RAM, ROM, and CMOS.RAM chips hold the program and data that the CPU is presently processing, everything in most types of RAM is lost as soon as the microcomputer is turned off or a power failure.ROM chips have programs built into them at the factory. ROM chips are not volatile and cannot be changed by the user.CMOS chip provides flexibility and expandability for a computer system. It contains essential information that is required every time the computer system is turned on. It is powered by a battery and does not lose its contents when the power is turned. Its contents can be changed to reflect changes in the computer system.4.Identify five expansion cards and describe the function of each.Five expansion cards are: graphics cards, sound cards, modem cards, NIC and TV tuner cards.Graphics cards connect the system board to the computer’s monitor, they convert the internal electronic signals to video signals so they can be displayed on the monitor.Sound cards accept audio input from a microphone and convert it into a form that can be processed by the computer. They also convert internal electronic signals to audio signals.Modem cards allow distant computers to communicate with one another by converting electronic signals from within the system unit into electronic signals that can travel over telephone lines and other types of connections.NIC are used to connect a computer to one or more other computers.TV tuner cards can changes the TV signal into one that can be displayed on you monitor.5.Identify and describe four standard ports and two specialized ports.Four standard ports are: serial ports, parallel ports, universal serial bus ports and FireWire ports.Serial ports are often used to connect a mouse, keyboard, modem, and many other devices to the system unit.Parallel ports are used to connect external devices that need to send or receive a lot of data overa short distance.USB ports are gradually replacing serial and parallel ports.FireWire ports provide connections to specialized FireWire devices.CHAPTER71.Define input and output devices.Input is any data or instructions that are used by a computer. Input devices are hardware used to translate what people understand into a form that computers can process.2.Describe the three categories of output devices.①There are a widely of different pointing devices including the mouse, joystick, touch screen,light pen, and stylus.A mouse controls a pointer that is displayed on the monitor.A joystick is the most popular input device for computer games. You control game actions byvarying the pressure, speed, and direction of the joystick.A touch screen is a particular kind of monitor with a clear plastic outer layer.A light pen is a light-sensitive pen-like device.A stylus acts with the computer through handwriting recognition software.②There are three types of scanning devices: optical scanners, card readers, bar code readers,and character and mark recognition devices.An optical scanner accepts documents consisting of text and/or images and converts them to machine readable form.Card readers interpret encoded information.Bar code readers are either handheld wand readers or platform scanners.Character and mark recognition devices are scanners that are able to recognize special characters and marks.③Image capturing devices include digital cameras and digital video cameras.Digital cameras capture still images. Digital video cameras capture motion.④Audio input can take many forms including the human voice and music.Voice recognition systems accept voice commands to control computer operations and to create document.MIDI is a standard for connecting musical instruments to the system unit.3.Describe the three categories if output devices.The most widely used output devices are monitors, printers and audio output.Monitors present visual images of text and graphics.Printers translate information that has been processed by the system unit and present the information on paper.Audio output devices translate audio information from the computer into sounds that people can understand.4. Define output an output devices.Output is processed data or information. Output devices are hardware used to translate information that has been processed by the system unit into a form that humans can understands.5. What are combination input and output devices? Describe four such devices.Devices combine features of input devices such as scanners with features of output devices like printers are called combination input and output devices.Combination devices include fax machines, multifunction devices, Internet telephones, and terminals.A fax machine is a standard tool in nearly every office.Multifunction devices combine the capabilities of a scanner, printer, fax, and copying machine.Internet telephones are specialized input and output devices for receiving and sending voice communication.Terminals are input and output device that connect you to a mainframe or other type of computer.CHAPTER81.Discuss the traditional and high-capacity floppy disksThe traditional floppy disk is the 1.44MB 3-inch disk. They have a thin exterior jacket made of hard plastic to protect the flexible disk inside.The high capacity floppy disks are 3 inches in diameter. They are able to store more information, are thicker, and require special disk drives.2.What are the three types of hard disks? Describe three ways to improve hard diskperformance.There are three types of hard disks: Internal hard disk, hard-disk cartridge, and hard-disk pack.Three ways to improve the performance of hard disks are disk caching, redundant arrays ofinexpensive disks, and file compression/decompression.Disk caching improves hard-disk performance by anticipating data needs.Redundant arrays of inexpensive disks improve performance by expending external storage, improving access speed, and providing reliable storage.File compression and file decompression increase storage capacity by reducing the amount of space required to store data and programs.3.What are the two most common optical disc formats? What is hi def ? Describe the basictypes for each format.The two most common optical disc formats are CD and DVD. Hi def is the next generation of optical discs.①There are four basic types of CDs: read only, write once, rewritable, and Picture and PhotoCDs.Read only CDs cannot be written on or erased by the users, they are used to distribute large databases, references, and large software application packages.Write once CDs can be written to once, they are used to archive data and to record music download from the Internet.Rewritable CDs are similar to write once CDs except that the disks surface is not permanently altered when data is recorded.Picture and Photo CDs use a special format developed by Eastman Kodak to store digital images.②There are three types of DVDs: read only, write once, and rewriteable.Read only DVDs can provide over two hours of very high-quality video and sound comparable to that found in motion picture theatres.Write once DVDs are typically used to create permanent archives for large amounts of data and to record videos.Rewriteable DVDs are competing rewriteable formats.4.Discuss solid-state storage, Internet hard drives, and magnetic tape. What are theadvantages and disadvantages of each?Solid-state storage does not have moving parts. Internet drives use the Internet to store data and information. Magnetic tape provides sequential access for backup.Solid-state storage is more expensive than the others, it is more reliable and requires less power.Internet drives are low cost and the flexibility to access information from any location using the Internet. Access speed is slower.Magnetic tapes provide slower sequential access. It is an effective and commonly used tool for backing up data.5. Discuss mass storage, enterprise storage system, and mass storage devices.Mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. Enterprise storage systems are the computer storage systems designed for large-scale, high-technology environments of the modern enterprises.Mass storage Devices have been described as mass storage include tape libraries, RAID systems, hard disk drives, magnetic tapedrives, optical disc drives, magneto-optical disc drives, drum memory, floppy disk drives, punched tape and holographic memory.CHAPTER91.Define and discuss connectivity, the wireless revolution, and communications.①Connectivity is a concept related to using computer networks to link people and resources.②The single most dramatic change in connectivity and communications in the past five yearshas been the widespread use of mobile or wireless telephones. This wireless technology allows individuals to stay connected with one another from almost anywhere at any time, the revolution is just beginning.③Communication systems transmit data from one location to another. Every communicationsystem has four basic elements: sending and receiving devices, communication channel, connection devices, and data transmission specifications.2.Identify and describe the various physical and wireless communications.①Physical connections use a solid medium to connect sending and receiving devices.These connections include telephone lines, coaxial cable, and fiber-optic cables.Telephone lines consist of twisted pair cable, they have been the standard transmission medium for years for both voice and data.Coaxial cable replaces the multiple wires of telephone lines with a single solid-copper core.Fiber-optic cable transmits data as pulses of light through tiny tubes of glass.②Wireless connections use the air to connect sending and receiving devices.Primary technologies used for wireless connections are infrared, broadcast radio, microwave, and satellite.Infrared uses infrared light waves to communicate over short distances.Broadcast radio communication uses special sending and receiving towers called transceivers.Microwave communication uses high-frequency radio waves.Satellite communication uses satellites orbiting about 22000 miles above the earth as microwave relay stations.3.Identify the standard Internet protocol and discuss its essential features.The standard protocol for the Internet is TCP/IP. The essential features of this protocol involve: identifying sending and receiving devices and reformatting information for transmission across the Internet.Identification: Every computer on the Internet has a unique number address called an IP address, the Internet uses IP addresses to deliver e-mail and to locate Web sites.Reformatting: Information sent or transmitted across the Internet usually travels through numerous interconnected networks. Before the massage is sent, it is reformatted or broken downinto small parts called packets, at the receiving end, the packets are reassembled into the correct order.4.Define and discuss the four principal network topologies.The four principal network topologies are star, bus, ring, and hierarchical.In a star network, a number of small computers or peripheral devices are linked to a central unit, all communications pass through this central unit.In a bus network, each device in the network handles its own communication control.In a ring network, each device is connected to two other devices, forming a ring.The hierarchical network consists of several computers linked to a central host computer, other computers are also hosts to other, smaller computers or to peripheral devices.5.Define and discuss the three most common network strategies.The most common network strategies are terminal, client/server, and peer-to-peer systems.①In a terminal network system, processing power is centralized in one large computer. For theend user it is lack of control and flexibility.②Client/server network system use one computer to coordinate and supply services to othernodes on the network. One advantage of the client/sever network strategy is the ability to handle very large networks efficiently. Another advantage is the ability of powerful network management software to monitor and control network activities. The major disadvantages are the cost of installation and maintenance.③In a peer-to-peer network system, nodes have equal authority and can act as both clients andservers. The networks are inexpensive and easy to install, and they usually work well for smaller systems with fewer than 10 nodes.CHAPTER101.Discuss the impact of large database , private networks, the Internet, and the Web onprivacy.Large databases raise some serious concerns on privacy: identity theft and mistaken identity.The impact of private networks on privacy has the two parts: The first instance, of firms eavesdropping on employees, has inspired attempts at federal legislation. The second instance, in which online information services screen and reject messages, is a common activity with most commercial services.The internet brings illusion of anonymity, the web creates a history file, your web activity is monitored is by cookies. To respond to these privacy concerns, a code of fair information practice has been established.2.Discuss the carious kinds of computer criminals.Computer criminals are of five types:Employees: The largest category of computer criminals consists of those with the easiest access to computers-namely, employees.Outside users: Some suppliers or clients may have access to a company’s computer system.Hackers and crackers: Hackers are people who gain unauthorized access to a computer system for the fun and challenge of it. Crackers do the same thing but for malicious purposes.Organized crime: Members of organized crime groups have discovered that they can use computers just as people in legitimate businesses do, but for illegal purpose.Terrorists: Knowledgeable terrorist groups and hostile governments could potentially crash satellites and wage economic warfare by disrupting navigation and communication systems.3. What are the principal measures used to protect computer security? What is encryption?How is it used by corporations and individuals?Some of the principal measures to protect computer security are encryption, restricting access, anticipating disasters, and backing up data.Encryption is the conversion of data into a form, called a ciphertext that cannot be easily understood by unauthorized people.Corporations have use it for years that some law enforcement agencies are unable to wiretap messages from suspected criminals. Individuals are also using encryption programs to safeguard their private communications.4.What is ergonomics? How does computer use impact mental health? Physical health?Ergonomics is defined as the study of human factors related to things people use.The physical health matters related to computers that have received the most attention recently are the following: eyestrain and headache, back and neck pain, and repetitive strain injury.Computer technology creates some irritants that may be counter productive: noise, and electronic monitoring.5.Describe the basic elements of the Green PC and what you can do to protect theenvironment.The basic elements of the Green PC are: System unit, display, and manufacturing.As a computer user, you can do to help protect the environment are the following:conserve, recycle, and educate.。

计算机科学导论课后练习

计算机科学导论课后练习

《计算机科学导论》课后练习(翻译)(总32页)--本页仅作为文档封面,使用时请直接删除即可----内页可以根据需求调整合适字体及大小--Chapter 1 练习复习题1.定义一个基于图灵模型的计算机。

答:Turing proposed that all kinds of computation could be performed by a special kind of a machine. He based the model on the actions that people perform when involved in computation. He abstracted these actions into a model for a computational machine that has really changed the world.图灵模型假设各种各样的运算都能够通过一种特殊的机器来完成,图灵机的模型是基于各种运算过程的。

图灵模型把运算的过程从计算机器中分离开来,这确实改变了整个世界。

2.定义一个基于冯·诺伊曼模型的计算机。

答:The von Neumann Model defines the components of a computer, which are memory, the arithmetic logic unit (ALU), the control unit and the input/output subsystems.冯·诺伊曼模型定义了计算机的组成,它包括存储器、算术逻辑单元、控制单元和输入/输出系统。

3.在基于图灵模型的计算机中,程序的作用是什么答:Based on the Turing model a program is a set of instruction that tells the computer what to do.基于图灵模型的计算机中程序是一系列的指令,这些指令告诉计算机怎样进行运算。

《计算机导论》课后习题答案

《计算机导论》课后习题答案

第一章1、什么是计算机?答:计算机是一种能够按照事先存储的程序,自动、高速地对数据进行输入、处理、输出和存储的系统。

2、解释冯·诺依曼所提出的“储存程序”的概念。

答:由于计算机可以储存程序,从而使得计算机可以在程序的控制下自动地完成各种操作,而无需人工干涉。

3、计算机有那些特点?答:运算速度快、运算精度高、具有记忆能力、具有逻辑判断能力和存储程序。

4、计算机发展过程中各阶段的主要特点是什么?答:电子计算机发展的四个阶段是:第一代( 1946 ~ 1957 ),以电子管为逻辑部件,以阴极射线管、磁芯和磁鼓等为存储手段。

软件上采用机器语言,后期采用汇编语言。

第二代( 1958 ~ 1965 ),以晶体管为逻辑部件,内存用磁芯,外存用磁盘。

软件上广泛采用高级语言,并出现了早期的操作系统。

第三代( 1966 ~ 1971 ),以中小规模集成电路为主要部件,内存用磁芯、半导体,外存用磁盘。

软件上广泛使用操作系统,产生了分时、实时等操作系统和计算机网络。

第四代( 1971 至今),以大规模、超大规模集成电路为主要部件,以半导体存储器和磁盘为内、外存储器。

在软件方法上产生了结构化程序设计和面向对象程序设计的思想。

另外,网络操作系统、数据库管理系统得到广泛应用。

微处理器和微型计算机也在这一阶段诞生并获得飞速发展。

5、信息化社会对计算机人才的素质和知识结构有哪些要求?答:a)掌握计算机科学与技术的理论和本学科的主要知识体系。

b)在确定的环境中能够理解并且能够应用基本的概念、原理、准则,具备对工具及技巧进行选择与应用的能力。

c)完成一个项目的设计与实现,该项目应该涉及到问题的标识、描述与定义、分析、设计和开发等,为完成的项目撰写适当的文档。

该项目的工作应该能够表明自己具备一定的解决问题和评价问题的能力,并能表现出对质量问题的适当的理解和认识。

d)具备在适当的指导下进行单独工作的能力,以及作为团队成员和其他成员进行合作的能力。

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CHAPTER11.Explain the five parts of an information system .What part do people playin this system?An information system has five parts: people, procedures, software, hardware and data.People: Are end users who use computer to make themselves more productive.Procedures: Specify rules or guidelines for computer operations.Software: Provides step-by-step instructions for computer hardware.Hardware: Processes the data to create information.Data: Consist of unprocessed facts including text, numbers, image and sounds.People are the most important part of any information system.2.What is system software? What kinds of programs are included in systemsoftware?System software helps the computer manage its own internal resources. It includes three kinds of programs: operating systems, utilities and device drivers programs.3.Define and compare basic and specialized application software. Describesome different types of basic application software. Describe some types of specialized applications.Basic applications are the kinds of programs to be considered computer competent.Specialized applications are more narrowly focused on specific disciplines and occupations.Basic applications have some types, such as browser, word processor, spreadsheet ,and so on.Also specialized applications have many types, some of the best known are graphics, audio and video, multimedia, Web authoring ,and artificial intelligence programs.4.Describe the different types of computer. What is the most common type?What are the types of microcomputers?There are four types of computers: supercomputers, mainframe computers, minicomputers, and microcomputers.Supercomputers are the most powerful type of computer.Mainframe computers occupy specially wired, air-conditioned rooms, they are capable of great processing speeds and data storage.Minicomputers are refrigerator sized machines.Microcomputers are the least powerful, yet the most widely used and fastest-growing, type of computer.Microcomputers are the most common type of computers.There are four types of microcomputers: Desktop computers, Notebook computers, Handheld computers and PDA.5.What is connectivity? How are the wireless revolution and connectivityrelated? What is a computer network? What is the Internet? What is the Web?Connectivity is the capability of you microcomputer to share the information with other computers.Wireless revolution dramatically affect connectivity.A computer network is a communications system connecting two or morecomputers.Internet is the largest network in the world.The Web provides a multimedia interface to the numerous resources available on the Internet.CHAPTER21.Discuss the uses of the Internet. Which activities have you participated in?Which one do you think is the most popular?The most common uses of the Internet are the following: communicating, shopping, searching, entertainment, education, and so on. I have participated in almost all of them. I think communicating is the most popular.2.Explain the differences between the two most common types of providers.The two most common types of providers are National and wireless.National service providers provide access through standard telephone connections.Wireless service providers provide Internet connections for computers with wireless modems and a wide array of wireless devices.3.What are the basic elements of an e-mail message?A typical e-mail message has three basic elements: header, message and signature.4.What is social networking ? Describe the three types if social networkingsites.Social networking is the grouping of individuals into specific groups. There are three basic categories of social networking sites: reuniting, friend-of-a-friend andcommon interestReuniting sites are designed to connect people who have known one another but have lost touch.Friend-of-a-friend sites are designed to bring together two people who do not know one another but share a common friend.Common interest sites bring together individuals that share common interests or hobbies.5.Describe the different types of search engines. Given an example of the typeof search each engine is best for.There are three types of search engines: crawler-based search engines, metasearch engines and specialized search enginesCrawler-based search engines, such as Google, create their listings automatically. Metasearch engines are programs that automatically submit your search request to several engines simultaneously. The metasearch engines receives the results, eliminates duplicates, orders the hits, and then provides the edited list to you .one of the best known is Dogpile.Specialized search engines focus on subject-specific Web sites. such as Environment.CHAPTER31.Explain the difference between general-purpose and special-purposeapplications.General-purpose application are widely used in nearly every discipline and occupation. They include word processors, spreadsheets, database management systems and presentation graphics.Specialized application includes thousands of other programs that are more narrowly focused on specific disciplines and occupations.2.Discuss the common features of most software programs. Describe the newinterface to what-if analysis?Most applications use a GUI, use windows to display information, and have menus to present commands.3.What is the difference between a function and a formula? How is a formularelated to what-if analysis?A formula is an instruction to calculate or process. Functions are prewrittenformulas. A formula related to what-if analysis is called recalculation.4.What are presentation graphics programs? How are they used?Presentation graphics are programs that combine a variety of visual objects to create attractive, visually interesting presentation. People in a variety of setting and situations use presentation graphics programs to make their presentations more interesting and professional.5.What is the difference between an integrated package and a software suite?What are the advantages and disadvantages od each?An integrated package is a single program that provides the functionality of a word processor, spreadsheet, database manager, and more. The primary disadvantage of an integrated package is that the capabilities of each function are not as extensive as in the individual programs. The primary advantages are cost and simplicity.A software suite is a collection of separate application programs bundledtogether and sold as a group. It is significantly less expensive to buy a suite of applications than to buy each application separatelyCHAPTER41.Describe graphics , including desktop publishers, image editors, illustrationprograms, image galleries, and graphics suites.Graphics are widely used to analyze data and to create professional-looking presentations; Desktop publishers focus on page design and layout and provide greater flexibility; Image editors are programs for creating and editing bitmap images; Illustration programs are used to create and to edit vector images; Image galleries are libraries of electronic images. These images are used for a wide variety of applications from illustrating textbooks to providing visual interest to presentations;Graphics suites are some companies combining their separate graphics programs in groups.2.Discuss audio and video editing software.Audio editing software allows you to create and edit audio clips, most software allow you to add audio effects to your tracks. Video editing software allows you to reorganize, add effects, and more to your digital video footage.3.What is multimedia? How are multimedia presentations developed?Multimedia is the integration of all sorts of media into one presentation. The creation of interactive multimedia presentations follows several steps: Plan, Design, Create and Support.4.Describe Web authoring , including Web site design and Web authoringprograms.Creating a site is called Web authoring. A web site design is an interactive multimedia form of communication, designing a web site begins with determining the site’s overall content, the overall site design is commonly represented in a graphical map. More specialized and powerful programs, called Web authoring programs, are typically used to create sophisticated commercial sites.5.Discuss three areas of artificial intelligence.The three areas of artificial intelligence are virtual reality, knowledge-based systems and robotics. Virtual reality is an artificial, or simulated, reality generated in 3-D by a computer. Knowledge-based systems are a type of artificial intelligence that uses a database to provide assistance to users.Robotics is the field of study concerned with developing and using robots.CHAPTER51.Describe system software. What are the four types of system programs?System software works with end users, application software, and computer hardware to handle the majority of technical details. It consists of four types of programs: operating systems, utilities, device drivers and language translators.2.What are the basic functions of every operating system? What are the threebasic operating system categories?The basic functions of every operating system are : managing computer resources, providing a user interface, and running applications. The three basic operating system categories are: embedded, network and stand-alone.3.Explain the differences and similarities between Windows, Mac OS, andLinux.Windows is by far the most popular microcomputer operating system today. It comes in a variety of different versions and is designed to run with Intel and Intel-compatible microprocessors. Mac OS is not nearly as widely used as the Windows operating system. It is a powerful, easy-to-use operating system that is popular with professional graphic designs, desktop publishers, and manyhome users. While Windows, the Mac OS are proprietary operating systems, Linux is not. It is open source software free and available from many sources, including the Web.4.Discuss utilities. What are the five most essential utilities? What is a utilitiessuite?Utilities are specialized programs designed to make computing easier. The five most essential utilities are: troubleshooting or diagnostic programs, antivirus programs, uninstall programs, backup programs and file compression programs.Utility suites combine several programs into one package.5.Explain the role of device drivers. Discuss the Add Printer Wizard andWindows Update.A device driver works with the operating system to allow communicationbetween the device and the rest of the computer system. Each time the computer system is started, the operating system loads all of the device drivers into memory. Whenever a new device is added to a computer system, a new device driver must be installed before the device can be used.Add Printer Wizard provides step-by-step guidance to select the appropriate printer driver and to install that driver. Windows uses Windows Update to makereinstalling or updating device drivers easily.CHAPTER61.Describe the four basic types of system units.There are four basic types of system units: Desktop system units, Notebook system units, T ablet PC system units, and Handheld computer system units.Desktop system units typically contain the system’s electronic components and selected secondary storage devices.Notebook system units are portable and much smaller. They contain the electronic components, selected secondary storage devices, and input device.Tablet PC system units are highly portable devices that support the use of a stylus or pen to input commands and data.Handheld computer system units are the smallest and are designed to fit into the palm of one hand.2.Describe the two basic components of the CPU.The two basic components are: the control unit and the arithmetic-logic unit.Control unit tells the rest of the computer system how to carry out a program’s instructions.Arithmetic-logic unit performs two types of operations---arithmetic and logical.3.What are the differences and similarities between the three types ofmemory?There are three types of memory chips: RAM, ROM, and CMOS.RAM chips hold the program and data that the CPU is presently processing, everything in most types of RAM is lost as soon as the microcomputer is turned off or a power failure.ROM chips have programs built into them at the factory. ROM chips are not volatile and cannot be changed by the user.CMOS chip provides flexibility and expandability for a computer system. It contains essential information that is required every time the computer system is turned on. It is powered by a battery and does not lose its contents when the power is turned. Its contents can be changed to reflect changes in the computer system.4.Identify five expansion cards and describe the function of each.Five expansion cards are: graphics cards, sound cards, modem cards, NIC and TV tuner cards.Graphics cards connect the system board to the computer’s monitor, theyconvert the internal electronic signals to video signals so they can be displayed on the monitor.Sound cards accept audio input from a microphone and convert it into a form that can be processed by the computer. They also convert internal electronic signals to audio signals.Modem cards allow distant computers to communicate with one another by converting electronic signals from within the system unit into electronic signals that can travel over telephone lines and other types of connections.NIC are used to connect a computer to one or more other computers.TV tuner cards can changes the TV signal into one that can be displayed on you monitor.5.Identify and describe four standard ports and two specialized ports.Four standard ports are: serial ports, parallel ports, universal serial bus ports and FireWire ports.Serial ports are often used to connect a mouse, keyboard, modem, and many other devices to the system unit.Parallel ports are used to connect external devices that need to send or receivea lot of data over a short distance.USB ports are gradually replacing serial and parallel ports.FireWire ports provide connections to specialized FireWire devices.CHAPTER71.Define input and output devices.Input is any data or instructions that are used by a computer. Input devices are hardware used to translate what people understand into a form that computers can process.2.Describe the three categories of output devices.①There are a widely of different pointing devices including the mouse, joystick,touch screen, light pen, and stylus.A mouse controls a pointer that is displayed on the monitor.A joystick is the most popular input device for computer games. You controlgame actions by varying the pressure, speed, and direction of the joystick.A touch screen is a particular kind of monitor with a clear plastic outer layer.A light pen is a light-sensitive pen-like device.A stylus acts with the computer through handwriting recognition software.②There are three types of scanning devices: optical scanners, card readers, barcode readers, and character and mark recognition devices.An optical scanner accepts documents consisting of text and/or images and converts them to machine readable form.Card readers interpret encoded information.Bar code readers are either handheld wand readers or platform scanners.Character and mark recognition devices are scanners that are able to recognize special characters and marks.③Image capturing devices include digital cameras and digital video cameras.Digital cameras capture still images. Digital video cameras capture motion.④Audio input can take many forms including the human voice and music.Voice recognition systems accept voice commands to control computer operations and to create document.MIDI is a standard for connecting musical instruments to the system unit.3.Describe the three categories if output devices.The most widely used output devices are monitors, printers and audio output.Monitors present visual images of text and graphics.Printers translate information that has been processed by the system unit and present the information on paper.Audio output devices translate audio information from the computer into sounds that people can understand.4. Define output an output devices.Output is processed data or information. Output devices are hardware used to translate information that has been processed by the system unit into a form that humans can understands.5. What are combination input and output devices? Describe four such devices.Devices combine features of input devices such as scanners with features of output devices like printers are called combination input and output devices.Combination devices include fax machines, multifunction devices, Internet telephones, and terminals.A fax machine is a standard tool in nearly every office.Multifunction devices combine the capabilities of a scanner, printer, fax, and copying machine.Internet telephones are specialized input and output devices for receiving and sending voice communication.Terminals are input and output device that connect you to a mainframe or other type of computer.CHAPTER81.Discuss the traditional and high-capacity floppy disksThe traditional floppy disk is the 1.44MB 3-inch disk. They have a thin exterior jacket made of hard plastic to protect the flexible disk inside.The high capacity floppy disks are 3 inches in diameter. They are able to store more information, are thicker, and require special disk drives.2.What are the three types of hard disks? Describe three ways to improve harddisk performance.There are three types of hard disks: Internal hard disk, hard-disk cartridge, and hard-disk pack.Three ways to improve the performance of hard disks are disk caching, redundant arrays of inexpensive disks, and file compression/decompression.Disk caching improves hard-disk performance by anticipating data needs.Redundant arrays of inexpensive disks improve performance by expending external storage, improving access speed, and providing reliable storage.File compression and file decompression increase storage capacity by reducing the amount of space required to store data and programs.3.What are the two most common optical disc formats? What is hi def ?Describe the basic types for each format.The two most common optical disc formats are CD and DVD. Hi def is the nextgeneration of optical discs.①There are four basic types of CDs: read only, write once, rewritable, and Pictureand Photo CDs.Read only CDs cannot be written on or erased by the users, they are used to distribute large databases, references, and large software application packages.Write once CDs can be written to once, they are used to archive data and to record music download from the Internet.Rewritable CDs are similar to write once CDs except that the disks surface is not permanently altered when data is recorded.Picture and Photo CDs use a special format developed by Eastman Kodak to store digital images.②There are three types of DVDs: read only, write once, and rewriteable.Read only DVDs can provide over two hours of very high-quality video and sound comparable to that found in motion picture theatres.Write once DVDs are typically used to create permanent archives for large amounts of data and to record videos.Rewriteable DVDs are competing rewriteable formats.4.Discuss solid-state storage, Internet hard drives, and magnetic tape. Whatare the advantages and disadvantages of each?Solid-state storage does not have moving parts. Internet drives use the Internetto store data and information. Magnetic tape provides sequential access for backup.Solid-state storage is more expensive than the others, it is more reliable and requires less power.Internet drives are low cost and the flexibility to access information from any location using the Internet. Access speed is slower.Magnetic tapes provide slower sequential access. It is an effective and commonly used tool for backing up data.5. Discuss mass storage, enterprise storage system, and mass storage devices.Mass storage refers to the storage of large amounts of data in a persisting and machine-readable fashion. Enterprise storage systems are the computer storage systems designed for large-scale, high-technology environments of the modern enterprises.Mass storage Devices have been described as mass storage include tape libraries, RAID systems, hard disk drives, magnetic tape drives, optical disc drives, magneto-optical disc drives, drum memory, floppy disk drives, punched tape and holographic memory.CHAPTER91.Define and discuss connectivity, the wireless revolution, andcommunications.①Connectivity is a concept related to using computer networks to link peopleand resources.②The single most dramatic change in connectivity and communications in thepast five years has been the widespread use of mobile or wireless telephones.This wireless technology allows individuals to stay connected with one another from almost anywhere at any time, the revolution is just beginning.③Communication systems transmit data from one location to another. Everycommunication system has four basic elements: sending and receiving devices, communication channel, connection devices, and data transmission specifications.2.Identify and describe the various physical and wireless communications.①Physical connections use a solid medium to connect sending and receivingdevices.These connections include telephone lines, coaxial cable, and fiber-optic cables.Telephone lines consist of twisted pair cable, they have been the standard transmission medium for years for both voice and data.Coaxial cable replaces the multiple wires of telephone lines with a single solid-copper core.Fiber-optic cable transmits data as pulses of light through tiny tubes of glass.②Wireless connections use the air to connect sending and receiving devices.Primary technologies used for wireless connections are infrared, broadcast radio, microwave, and satellite.Infrared uses infrared light waves to communicate over short distances.Broadcast radio communication uses special sending and receiving towers called transceivers.Microwave communication uses high-frequency radio waves.Satellite communication uses satellites orbiting about 22000 miles above the earth as microwave relay stations.3.Identify the standard Internet protocol and discuss its essential features.The standard protocol for the Internet is TCP/IP. The essential features of this protocol involve: identifying sending and receiving devices and reformatting information for transmission across the Internet.Identification: Every computer on the Internet has a unique number address called an IP address, the Internet uses IP addresses to deliver e-mail and to locate Web sites.Reformatting: Information sent or transmitted across the Internet usually travels through numerous interconnected networks. Before the massage is sent, it is reformatted or broken down into small parts called packets, at the receiving end,the packets are reassembled into the correct order.4.Define and discuss the four principal network topologies.The four principal network topologies are star, bus, ring, and hierarchical.In a star network, a number of small computers or peripheral devices are linked to a central unit, all communications pass through this central unit.In a bus network, each device in the network handles its own communication control.In a ring network, each device is connected to two other devices, forming a ring.The hierarchical network consists of several computers linked to a central host computer, other computers are also hosts to other, smaller computers or to peripheral devices.5.Define and discuss the three most common network strategies.The most common network strategies are terminal, client/server, and peer-to-peer systems.①In a terminal network system, processing power is centralized in one largecomputer. For the end user it is lack of control and flexibility.②Client/server network system use one computer to coordinate and supplyservices to other nodes on the network. One advantage of the client/severnetwork strategy is the ability to handle very large networks efficiently. Another advantage is the ability of powerful network management software to monitor and control network activities. The major disadvantages are the cost of installation and maintenance.③In a peer-to-peer network system, nodes have equal authority and can act asboth clients and servers. The networks are inexpensive and easy to install, and they usually work well for smaller systems with fewer than 10 nodes.CHAPTER101.Discuss the impact of large database , private networks, the Internet, andthe Web on privacy.Large databases raise some serious concerns on privacy: identity theft and mistaken identity.The impact of private networks on privacy has the two parts: The first instance, of firms eavesdropping on employees, has inspired attempts at federal legislation. The second instance, in which online information services screen and reject messages, is a common activity with most commercial services.The internet brings illusion of anonymity, the web creates a history file, your web activity is monitored is by cookies. To respond to these privacy concerns, a code of fair information practice has been established.2.Discuss the carious kinds of computer criminals.Computer criminals are of five types:Employees: The largest category of computer criminals consists of those with the easiest access to computers-namely, employees.Outside users: Some suppliers or clients may have access to a company’s computer system.Hackers and crackers: Hackers are people who gain unauthorized access to a computer system for the fun and challenge of it. Crackers do the same thing but for malicious purposes.Organized crime: Members of organized crime groups have discovered that they can use computers just as people in legitimate businesses do, but for illegal purpose.Terrorists: Knowledgeable terrorist groups and hostile governments could potentially crash satellites and wage economic warfare by disrupting navigation and communication systems.3. What are the principal measures used to protect computer security? Whatis encryption? How is it used by corporations and individuals?Some of the principal measures to protect computer security are encryption,restricting access, anticipating disasters, and backing up data.Encryption is the conversion of data into a form, called a ciphertext that cannot be easily understood by unauthorized people.Corporations have use it for years that some law enforcement agencies are unable to wiretap messages from suspected criminals. Individuals are also using encryption programs to safeguard their private communications.4.What is ergonomics? How does computer use impact mental health?Physical health?Ergonomics is defined as the study of human factors related to things people use.The physical health matters related to computers that have received the most attention recently are the following: eyestrain and headache, back and neck pain, and repetitive strain injury. Computer technology creates some irritants that may be counter productive: noise, and electronic monitoring.5.Describe the basic elements of the Green PC and what you can do to protectthe environment.The basic elements of the Green PC are: System unit, display, and manufacturing.As a computer user, you can do to help protect the environment are the。

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