计算机专业英语 Computer English. 高等学校精品规划教材 主编：支丽平 出版社：中国水利水电出版社. 任课教师：张 弛. 湖南城市学院计算机科学系. 教学目标 教学内容. Unit 4 Network Technique. 了解计算机网络的发展史 理解网络安全的相关理论 了解虚拟化技术 掌握电子商务的相关技术 了解目前已经广泛使用的局域网技术. 教学目标. Text 1 Evolution of computer networks Text 2 Network Security
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Unit 4 Network Technique
Earlier networks provided the necessary information exchange services but were limited to basically just this service. The information availability stimulated more imaginative uses of this information. As this occurred and the technology of networks improved, new applications arose. These new applications not only used information exchange but also remote job execution. It began simply as sending a batch job down the link to a less busy host, having the job completed there, and then shipping the results back to the originator.Text 1 Evolution of computer networks
track [træk] n. 【计算机】数据磁道
cable ['keibl] n.电缆
coaxial ['kəu'æksəl] adj. 同轴传输线的
transportation [trænspɔ:'teiʃən] n. 运输，运输系统，运输工具
fiber ['faibə] n. 光纤
configuration [kənfigju'reiʃən] n. 【计算机】 配置
terminology [tə:mi'nɔlədʒi] n. 用辞，术语
microwave ['maikrəuweiv] n. 微波
dedicated ['dedikeitid] adj. 【计算机】(装置、程序、系统等)专用的
coalition [kəuə'liʃən] n. 结合，合并，联合
distributed [dis'tribju:tid] vt. 分布的，分布式的
loose [lu:s] adj. 宽松的，不牢固的，不精确的Words and Expressions
investigate [in'vestigeit] v. 【计算机】 研究
long-haul ['lɔŋ'hɔ:l; 'lɔ:ŋ-] adj.长远距的
metropolitan [metrə'pɔlit(ə)n] n. 大都市的居民，大主教，母国的居民adj. 大都市的
vehicle ['vi:ikl] n. 传播媒介，工具，手段，交通工具，车辆
congestion [kən'dʒestʃən] n. 【计算机】 拥挤
routing ['ru:tiŋ; 'rau-] n路由选择，路径选择
invocation [invəu'keiʃən] 【计算机】调用
availability [əveilə'biliti] n. 有效，有用，有益.Words and Expressions
emphasi ['emfəsis] n. 强调，重点
stimulate ['stimjuleit] vt. 刺激，激励，鼓舞
batch [bætʃ] n.批， 成批， 分批
originator [ə'ridʒəneitə(r)] n. 创始人，发起人
sufficed [sə'fais] v. 足够，使...满足，合格
synchronization [siŋkrənai'zeiʃən] 同步化
shortfall ['ʃɔ:tfɔ:l] n. 不足之量，差额
throughput ['θru:put] n.【计算机】(计算机输入输出信息的)吞吐量，通过量，总处理能力
turnaround [‘tɜ:nəraʊnd] n.转变，突然好转Words and Expressions
LANs abbr.局域网 (local area networks)
spectrum ['spektrəm] n. 光谱，（比喻）范围， 系列
fiber ['faibə] n. 纤维
memoranda [memə'rændə] n. 备忘录(便条)21世纪大英汉词典》concurrently [kən'kʌrəntli] adv. 同时(兼)
plethora ['pleθərə] n. 过量，过剩
vendor ['vendɔ:] n. 厂商
Aloha [ɑ:'ləuhɑ:] int. 哈罗，欢迎，再见21世纪大英汉词典》WAN [wɔn] (wide area network)广域网Words and Expressions
（ ）1. The term network can mean a same thing.
（ ）2. Users found that the network could offer information sharing only.
（ ）3. The earliest concept of a network was of a loose binding together of devices or resources for sharing.
（ ）4. An early computer network that exhibited these traits was the Internet.
（ ）5. Because of the wide distances， delays of minutes were commonplace and caused added overhead in performing otherwise simple tasks.
（ ）6. Local area networks began showing up on the networking landscape in the early to mid 1960s as mostly research activities in universities and government laboratories.
（ ）7. We find wide area networks in our homes through cable modems and phone modems， automobiles via wireless technologies， banking (e.g.， ATMs)， schools via Internet connections， businesses， government， and industry.
（ ）8. There are too many aspects of information exchange and data processing in which a LAN cannot be found.
（ ） 9. LANs are used to connect all personal computers in offices， classrooms， factory floors， retail establishments， and now even many homes.
（ ）10. Large banks， such as the World Bank， have adopted LANs as the means to interconnect their various local sites into smaller networks linked together by wide area networks.Exercises
1. __________was first brought on-line in 1969 as a research tool to investigate long-haul network issues and to provide a tool for research and development solutions.
2. __________ has evolved into the Internet， connecting millions of computers over local area networks， metropolitan area networks， and other wide area networks.
3. __________are finding their way into all aspects of modern society.
4. Large banks， such as the World Bank， have adopted __________ as the means to interconnect their various local sites into smaller networks linked together by wide area networks.Exercises
In the transport layer, entire connections can be encrypted, end to end, that is, process to process. For maximum security, end-to-end security is required.
Finally, issues such as user authentication and nonrepudiation can only be handled in the application layer.
Since security does not fit neatly into any layer, it does not fit into any chapter of this book. For this reason, it rates its own chapter.Text 2 Network Security
loom [lu:m] n. 织布机v. 朦胧地出现，隐约可见
horizon [hə'raizn] n. 地平线；视野；眼界.
pitfall ['pitfɔ:l] n. 陷阱，诱惑，阴谋
algorithm ['ælgəriðəm] 算法
sin [sin] n. 罪，罪孽v. 犯罪
nosy ['nəuzi] adj. 鼻子大的，好管闲事的，爱追问的
recipient [ri'sipiənt] n. 接受者
authorized ['ɔ:θəraizd] adj. 经认可的，审定的，经授权的21世纪大英汉词典》purportedly [pə:'pɔ:tidli，'pə:p-，'pə:pət-] ad. 据称
IRS abbr. Internal Revenue Service 美国国税局
Mafia ['mɑ:fiə] n. 黑手党，秘密政党
legitimate [l i'dʒitimit] a. 合法的，正当的v. 使合法
malicious [mə‘liʃəs] a. 怀恶意的，恶毒的Words and Expressions
outsmart [aut'smɑ:t] v. 比...更聪明，打败
adversary ['ædvəsəri] n. 敌手，对手
thwart [θwɔ:t] a. 横坐板v. 反对，阻碍ad. 横过
perpetrate ['pə:pitreit] v. 做，犯
tapping ['tæpiŋ] n. 开孔(导出液体，放液，流出口，浇铸，抽头)
insider [in'saidə(r)] n. 内部的人，会员，知道内情的人
grudge [grʌdʒ] n. 怨恨，恶意v. 怀恨，嫉妒，吝惜
intertwined [intə:'waind] a. 互相缠结的，缠绕在一起的
secrecy ['si:krisi] n. 秘密(保密，隐蔽)
authentication[ɔ:，θenti'keiʃən] n. 证明，鉴定.
confidentiality [‘kɔnfi，denʃi’æləti] n. 秘而不宣，保密Words and Expressions
doohickey ['du:，hiki] n. 小玩意，装置，窍门
malicious [mə'liʃəs] a. 怀恶意的，恶毒的
adversary ['ædvəsəri] n. 敌手，对手
transit ['trænsit] n. 经过，运输v. 横越
concoct [kən'kɔkt] vt.调制，配制
photocopy ['fəutəu，kɔpi] n. 影印v. 影印
tampering ['tæmpəriŋ] a. 干预的，干涉的
sealed [si:ld] a. 封口的，密封的
wiretapping ['waiə，tæpiŋ] vt.wiretap的变形n.搭线窃听adj.搭线窃听的
tube [‘tju:b] n. 地铁，电子管，显像管，管，软管Words and Expressions
encrypt [in'kript] vt. 把…编码
decrypt [di:'kript] v. 译，解释
oblivious [ə'bliviəs] a. 没注意到，或不知道
vulnerable ['vʌlnərəb(ə)l] a. 易受伤害的，有弱点的
lax [læks] a. 松的，松懈的，不严的
slip [slip] n. 滑，错误，下跌v. 滑倒，犯错，减退
cryptography [krip'tɔgrəfi] 密码术，密码系统
sloppy ['slɔpi] a. 被泼水弄湿的，泥泞的，多阴雨的
inattention [inə'tenʃən] n. 不注意，粗心，疏忽
debug [di:'bʌɡ] vt. 【计算机】调试；排除(程序)中的错误，排除故障
loophole ['lu:phəʊl] n. 枪眼，小窗，换气孔Words and Expressions
（ ）1. Network security problems can be divided roughly into three closely intertwined areas: secrecy, authentication, and integrity control.
（ ）2. All these issues (secrecy, authentication, nonrepudiation, and integrity control) do not occur in traditional systems.
（ ）3. Integrity and secrecy are achieved by using registered mail and locking documents up.
（ ）4. With electronic checks, the original and the copy are distinguishable.
（ ）5. Tampering can usually be detected by handwriting, ink, and paper experts. None of these options are available electronically.
（ ）6.In the transport layer, firewalls can be installed to keep good packets and bad packets out.
（ ）7.Issues such as user authentication and nonrepudiation can not be handled in the application layer.Exercises
1. For the first few decades of their existence, __________ were primarily used by university researchers for sending e-mail and by corporate employees for sharing printers.
2. __________, also called confidentiality, has to do with keeping information out of the hands of unauthorized users.
3. __________ deals with determining whom you are talking to before revealing sensitive information or entering into a business deal.
4. In the __________ layer, entire connections can be encrypted, end to end, that is, process to process.Exercises
Since 2005, virtualization software was adopted faster than anyone imagined, including the experts. There are three areas of IT where virtualization is making headroads, network virtualization, storage virtualization and server virtualization.Virtualization
Virtualization can be viewed as part of an overall trend in enterprise IT that includes autonomic computing, a scenario in which the IT environment will be able to manage itself based on perceived activity, and utility computing, in which computer processing power is seen as a utility that clients can pay for only as needed. The usual goal of virtualization is to centralize administrative tasks while improving scalability and work loads.Storage virtualization
layout ['lei,aut] n. 布局,安排,设计
breakthrough ['breikθru:] n. 突破
responsiveness [ri'spɔnsivnis] n. 响应性(反应性)
agility [ə'dʒiliti] n. 敏捷,灵活,轻快
complicate['kɔmplikeit] v. 弄复杂,使错综,使起纠纷
masking ['mɑ:skiŋ] n. 遮蔽
spare [spєə] n. 剩余,备用零件,备用轮胎a. 多余的,备用的,简陋的
utilization [ju:tilai'zeiʃən] n. 利用
multiple ['mʌltipl] a. 多样的,多重的n. 倍数
VMware虚拟机 虚拟电脑, 虚拟主机Words and Expressions
legacy ['legəsi] n. 祖先传下来之物,遗赠物
simulate ['simjuleit] vt. 模拟；装作
distribute [dis'tribju:tid] vt. 分布的,分布式的
consolidation [kən,sɔli'deiʃən] n. 巩固,团结,合并
splitting up n. 分裂
bandwidth ['bændwidθ] n. 频带宽度(通带宽度)subscriber[sʌbs'kraibə] n. 签署者,捐献者,订户
tedious ['ti:diəs] adj. 沉闷的, 单调乏味的
satisfaction [,sætis'fækʃən] n. 满意
optimize ['ɔptimaiz] v. 使...完美,乐观,使...完善v.优化
scalability [,skeilə‘biliti] n. 可扩充性 延展性Words and Expressions
surge [sə:dʒ] n. 巨涌,汹涌,澎湃v. 汹涌,澎湃
complexity [kəm'pleksiti] n. 复杂(性),复杂的事物
administrator [əd'ministreitə] n. 管理人,行政官
administrative [əd'ministrətiv] a. 行政的,管理的
automatically [ɔ:tə'mætikli] a. 不经思索的ad. 自动地
storage area network (SAN) 存储区域网络
archiving [ɑ:'kəviŋ] n.【计算机】归档，胶片保管
hybrid ['haibrid] n. 混血儿,杂种,混合物a. 混合的,杂种的,混合语的
centralize ['sentrəlaiz] v. 集聚,集中,施行中央集权
autonomic [ɔ:tə'nɔmik] adj. 自治的,自律的
scenario [si'nɑ:riəu] n. 情节,剧本Words and Expressions
（ ）1. The intention of server virtualization is to let the user from have to understand and manage complicated details of server resources while increasing resource sharing and utilization and maintaining the capacity to expand later.
（ ）2. Vendors suggest that server virtualization allows a company to “scale-out”with multiple smaller computers as its processing needs grow rather than having to scale up to a more expensive multi-processor computer.
（ ）3. Server virtualization is frequently used to mask the complexities of server consolidation and is unrelated to the concept of the virtual machine, which uses a copy of an operating system to create the appearance of a full set of storage and other resources to each user.
（ ）4. Network virtualization is intended to optimize network speed, reliability, flexibility, scalability, and security.
（ ）5. Server virtualization is the pooling of physical storage from multiple network storage devices into what appears to be a single storage device that is managed from a central console.
（ ）6. Users cannot implement virtualization with software applications or by using hardware and software hybrid appliances.Exercises
1. __________ is the technique of managing systems and resources functionally, regardless of their physical layout or location.
2. __________ virtualization is the masking of server resources (including the number and identity of individual physical servers, processors, and operating systems) from server users.
3. __________ virtualization is intended to improve productivity, efficiency, and job satisfaction of the administrator by performing many of these tasks automatically, thereby disguising the true complexity of the network.
4. Storage virtualization is commonly used in a __________.
5. __________ virtualization helps the storage administrator perform the tasks of backup, archiving, and recovery more easily, and in less time, by disguising the actual complexity of the SAN.Exercises
Enterprise content management
Online shopping and order tracking
Online office suites
Domestic and international payment systems
Shopping cart software
Electronic ticketsBusiness applications
On the consumer level, electronic commerce is mostly conducted on the World Wide Web. An individual can go online to purchase anything from books or groceries, to expensive items like real estate. Another example would be online banking, i.e. online bill payments, buying stocks, transferring funds from one account to another, and initiating wire payment to another country. All of these activities can be done with a few strokes of the keyboard.
On the institutional level, big corporations and financial institutions use the internet to exchange financial data to facilitate domestic and international business. Data integrity and security are very hot and pressing issues for electronic commerce today.Forms
Electronic Funds Transfer (EFT) 电子货币转帐
supply chain management供应链管理
online transaction processing在线事务处理
electronic data interchange (EDI) 电子数据交换
inventory management systems存货管理
automated data collection systems自动数据收集系统
enterprise resource planning systems (ERP) 企业资源计划
data warehousing数据仓库Words and Expressions
Electronic Commerce 电子商务
business-to-business or B2B adj.企业对企业的（电子商务）
business-to-consumer or B2C adj. 企业对消费者的（电子商务）
travicom n. 旅游计算公司
Boston Computer Exchange波士顿计算机交易所
strictly adv. 严格地
prohibited [prəu'hibitid] 被禁止的
Online banking网上银行业务Words and Expressions
Facilitate [fə'siliteit] v. 帮助,使...容易,促进
Groceries ['ɡrəusəri] n. 食品；杂货
transferring [træns'fə:riŋ] 印字、中转、转移、传递[导,送,输,热]
strokes [strəuk] n. 中风
institutions [,insti'tju:ʃən] n. 体系
facilitate [fə'siliteit] v. 帮助,使...容易,促进
domestic [də'mestik] adj. 国内的,家庭的,驯养的n. 家仆,佣人
integrity [in'tegriti] n. 诚实,正直,完整,完善Words and Expressions
（ ）1. A small percentage of electronic commerce is conducted entirely electronically for virtual items such as access to premium content on a website.
（ ）2. Electronic commerce that is conducted between businesses and consumers, on the other hand, is referred to as business-to- business or B2B.
（ ）3．The growth and acceptance of credit cards, automated teller machines (ATM) and telephone banking in the 1980s were not forms of electronic commerce.
（ ）4. From the 1980s onwards, electronic commerce would additionally include enterprise resource planning systems (ERP), data mining and data warehousing.
（ ）5. On the business level, electronic commerce is mostly conducted on the World Wide Web.Exercises
1. __________ Commerce, commonly known as e-commerce or eCommerce, consists of the buying and selling of products or services over electronic systems such as the Internet and other computer networks.
2. Online retailers are sometimes known as e-tailers and online retail is sometimes known as __________.
3. Almost all big retailers have electronic commerce presence on the __________.
4. Electronic commerce that is conducted between businesses is referred to as business-to-business or__________.
5. Data integrity and __________ are very hot and pressing issues for electronic commerce today.Exercises
So critical is tyre performance to road transport costs that engineers at Volvo Truck have developed an RF transmitter for each tyre on its massive trucks to send constant information to an in-dash display to warn drivers when any of up to 50 tyres are at anything other than perfect pressure.
A quarter of truck breakdowns are caused by tyre failure, starting as slow leaks and sometimes ending in explosion but certainly adding to rolling resistance and reduced life of expensive rubber.Text 5 LAN-Cruising
The processor sifts reports from each wheel to find the most accurate average, signalling an errant tyre on a schematic of the wheel configuration on an LCD screen in the dash.
The system’s CPU is one of 25 in the vehicle, together providing far more computing firepower than for the Apollo 13 landings.Text 5 LAN-Cruising
While on-board computers have been increasingly gaining new tasks in trucks for nearly a decade, wireless networking has steadily replaced complex wiring looms to get information to the driver’s cab and beyond.
Already 30 per cent of the cost of a new car is in the electronics: the chips, wires and networks that support features ranging from automatic door locks to anti-lock brakes to airbag deployment.Text 5 LAN-Cruising
Today’s cars have half a dozen different proprietary networks that carry messages from control systems to the devices being operated. Until recently, each car manufacturer and car model had its own network parts. These are hardened, automotive-specific networks with ultra-reliable electronic components that can withstand vibration and operate in extreme heat and cold.Text 5 LAN-Cruising
Companies are converging on several standards for internal networks that address different speed requirements. At the same time carmakers are looking to extend the use of those networks to replace the spaghetti of wire used to support functions such as turning on the engine and operating lights.
More carmakers are going wireless to support a host of new navigation and safety services.
Bluetooth is the technology of choice to support mobile phones. The car industry is developing a special profile of the Bluetooth standard -dubbed Bluetooth Handsfree 2.0 - that will link a built-in microphone in the car to any mobile phone without requiring a docking station, allowing for hands-free calling.Text 5 LAN-Cruising
But Bluetooth is only one of the technologies that are emerging to connect the computer-based car to the outside world. The rising demand for in-vehicle entertainment services has carmakers looking at everything from satellite links to Dedicated Short Range Communications (DSRC) and Wi-Fi.
On the horizon are real-time news, information and entertainment services that are integrated with in-vehicle entertainment systems. The most promising way to deliver these services is digital satellite radio. With improvements in compression techniques and smaller antennas, digital satellite also could deliver streaming video.Text 5 LAN-Cruising
Further out on the horizon is in-vehicle support for Wi-Fi technology. In 2006, some car manufacturers have installed self-contained Wi-Fi to allow users to load music and files into the car. Users could download files and other content to the car such as traffic reports or news.
But use of Wi-Fi for Internet access while cars are in motion is still just a pipe dream today. You’d need to have Wi-Fi hot spots along the highway. That won’t happen anytime soon.Text 5 LAN-Cruising
subroutine [,sʌbru:'ti:n] n.子程序，【计算机】=subprogram21世纪大英汉词典》triggered ['triɡəd] adj. 有触发器的，触发器启动的，有扳机的
frequency ['fri:kwənsi] n. 频繁，频率
handler ['hændlə] n.处理程序21世纪大英汉词典》
latency ['leitənsi] n.潜伏，潜在，等待时间
queue [kju:] n.【计算机】等候行列，排队
scheme [ski:m] n. 方案,计划,阴谋；v. 计画,设计,体系，结构,图谋
idle [‘aidl] adj. 【机械学】空转的；慢转的；怠速的；【电子学】空载的；无功的Words and Expressions
Interpreter n.【计算机】 翻译器，译印机，解释程序，翻译程序
functionality [,fʌŋkəʃə'næliti] n. 函数性(泛函性,官能度) , 功能（尤指软件、硬件的功能）21世纪大英汉词典》conceptually [kən'septjuəli] adv. 概念地21世纪大英汉词典》parallel ['pærəlel] adj.【电子学、计算机】并联的；n.【电子学、计算机】并联的
potentially [pə'tenʃəli] adv. 潜在地，假定地.
MMU abbr.Memory Manager Unit内存管理单元
synchronization [,siŋkrənai'zeiʃən] n.同步化21世纪大英汉词典》semaphore ['seməfɔ:] n.信号灯,旗语
non-blocking adj.非阻塞Words and Expressions
allocate ['æləukeit] vi.&vt.【计算机】分配，指定，保留
extensible [ik'stensəbl] adj.可展开的，可伸展的，可延续的；可扩大的，可扩展的；可延伸的
downside ['daun,said] n. 消极面,负面
navigation [,nævi'geiʃən] n. 航行,航海
guarantee [,gærən'ti:] v.&n. 保证,担保；vt. 保证
RTOS abbr. Real Time Operating Systems实时操作系统
exotic [,iɡ‘zɔtik] adj. 1.外来的，非本地的；2.【核物理学】异的；极不稳定的Words and Expressions
（ ）1. The loop calls subroutines, each of which manages all of the hardware or software.
（ ）2. This gives programmers an environment different to a desktop operating system like Linux or Microsoft Windows, and is therefore very productive for development.
（ ）3. An interrupt could be generated for example by a timer in a predefined frequency, or by a serial port controller receiving a byte.
（ ）4. After the interrupt handler has finished, these tasks are executed by any loop.
（ ）5. A nonpreemptive multitasking system is very different to the simple control loop scheme, except that the loop is hidden in an API.
（ ）6. The advantages and disadvantages are very similar to the control loop, so that adding new software is easier, by simply writing a new task, or adding to the queue-interpreter.
（ ）7. Because of these complexities, it is common for organizations to buy a real-time operating system, allowing the application programmers to concentrate on device functionality and operating system services.
（ ）8. smaller systems can afford the overhead associated with a generic real time system, due to limitations regarding memory size, performance, and/or battery life.
（ ）9. Microkernels communicate efficiently by normal subroutine calls.
（ ）10. A microkernel is a logical step up from a real-time OS.Exercises
1. Some embedded systems are predominantly __________ controlled.
2. __________ communicate efficiently by normal subroutine calls.
3. Common examples of embedded monolithic __________ are Embedded Linux and Windows CE.
4. An interrupt could be generated for example by a __________ in a predefined frequency, or by a serial port controller receiving a byte.
5. A nonpreemptive multitasking system is very similar to the simple control loop scheme, except that the loop is hidden in an __________.Exercises