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Ways to Spot a Computer Science Student



1. When dating: ends up together in front of a computer.

2. In the street: he's the one carrying two or more notebooks.

3. In discussion: is the one who starts laughing hysterically when Microsoft is mentioned.

4. Anywhere: Red watery eyes, sleepy if awake before 4 pm.

5. Thinks a perfect Saturday Night is a fast FSP-connection to a base with plenty of GIFs, and a case of Heineken.

6. Cancels dates because he's too occupied with a new prog.

 

 



Unit 3. Computer Software

Reading and Vocabulary

1) apply ( V ) – применять; application ( N ) – приложение

2) coin (V) – создавать (новые слова или выражения)

3) comprise ( V ) – включать, охватывать, состоять из

4) consequence (N) – следствие, заключение

5) feature ( N ) – отличительная черта, свойство

6) firmware (N) – встроенные («зашитые») программы

7) implement (V) – реализовывать; implementation (N) – реализация

8) inventory (N) – запасы (на складе и т.п.)

9) maintain (V) – поддерживать, обслуживать; maintenance ( N ) – уход, обслуживание; maintainability (N) – ремонтопригодность

10) payroll (N) – платежная ведомость

11) perceive (V) – понимать, ощущать

12) permanent (A) – постоянный

13) rely on (V) – полагаться на; reliable (A) – надежный; reliability (N) – надежность

14) require (V) – требовать; requirement (N) – требование

15) routine (N) – стандартная программа

16) spreadsheet (N) – электронная таблица

17) succession ( N ) – последовательность; successive (A) – последовательный

18) temporary (A) – временный

19) word processor – текстовый процессор

Task 1. Match the descriptions on the left with these well-known applications.

1. word processor                              A. Adobe Photoshop

2. spreadsheet                                   B. Internet Explorer

3. virus protection                              C. Microsoft Word

4. browser                                                    D. Microsoft Excel

5. image editor                                   E. Microsoft PowerPoint

6. media player                                  F. Dr. Web

7. e-mail software                              G. The Bat

8. presentation software                   H. Adobe PageMaker

9. graphic design software               I. RealPlayer

 

Task 2. Read the text and write out the definitions of the following terms.

1) hardware

2) software program

3) system software

4) application software

5) network software

6) running (executing) a program

7) firmware

 

1) The term software is generally used for instructions that tell a computer what to do. Software comprises the entire set of programs, procedures, and routines associated with the operation of a computer system. The term was coined to differentiate these instructions from hardware – i.e., the physical components of a computer system. A set of instructions that directs a computer's hardware to perform a task is called a program, or software program.

2) The two main types of software are system software and application software. System software controls a computer's internal functioning, chiefly through an operating system, and also controls such peripherals as monitors, printers, and storage devices. Application software, by contrast, directs the computer to execute commands given by the user and may be said to include any program that processes data for a user. Application software thus includes word processors, spreadsheets, database management, inventory and payroll programs, and many other applications. A third software category is that of network software, which coordinates communication between the computers linked in a network.

3) Software is typically stored on an external long-term memory device, such as a hard drive or magnetic diskette. When the program is in use, the computer reads it from the storage device and temporarily places the instructions in random access memory (RAM). The process of storing and then performing the instructions is called running, or executing, a program. By contrast, software programs and procedures that are permanently stored in a computer's memory using a read-only memory (ROM) technology are called firmware, or hard software.

4) Computer programs, the software that is becoming an ever-larger part of the computer system, are growing more and more complicated, requiring teams of programmers and years of effort to develop. As a consequence, a new subdiscipline, software engineering, has arisen. The development of a large piece of software is perceived as an engineering task, to be approached with the same care as the construction of a skyscraper, for example, and with the same attention to cost, reliability, and maintainability of the final product.

The software-engineering process usually consists of several phases:

(1) identification and analysis of user requirements,

(2) development of system specifications (both hardware and software),

(3) software design (perhaps at several successively more detailed levels),

(4) implementation (actual coding),

(5) testing,

(6) maintenance.

 

Task 3. Answer these questions about the text.

1) What types of software do you know? Give examples of each type.

2) Where is software typically stored?

3) What are the phases of the software-engineering process?

Task 4. Decide  if  the  statement  is  true,  false  or  there  is  no  information

in the text.

1) Software consists of programs, procedures, and the physical components of a computer system.

2) Network software is produced by multiple software houses.

3) Computer programs are getting simpler and quicker to develop.

4) Software engineering is a complicated, multiphase process.

 

Task 5. Using the paragraph number references given, look back in the text and find words that have a similar meaning to.

1) invented (1) 2) execute (1) 3) comprises (2) 4) kept (3) 5) concern (4)

 

Task 6. Using the paragraph number references given, look back in the text and find words that have an opposite meaning to.

1) integrate (1) 2) for a long term (3) 3) appeared (4) 4) simple (4)

 

Task 7. Choose the correct words.

1. Turn on your computer. It will usually take a few minutes to __________.

    A. boot itself                     B. boot up               C. get booted

2. Windows XP, Macintosh OSX and Linux are __________.

    A. operating systems      B. operating tools   C. operators

3. On my computer, I have a picture of my cat as the __________.

    A. desktop background  B. desktop picture  C. desktop scene

4. Microsoft Word, Adobe Acrobat and CorelDraw are programs or ________.

    A. applicators                   B. appliers              C. applications

5. I keep all my digital photos in a __________ called "Photos".

    A. folder                            B. packet                 C. box

6. Deleted documents stay in the recycle bin until you __________ it.

    A. wash                            B. empty                 C. clean

7. If I leave my computer on without using it, after a while it goes into __________ mode.

    A. passive                        B. waiting                C. standby

Task 8. Fill in the gaps using the words below.

1. I couldn't open the document you e-mailed me. I don't have Microsoft Word ____________ on my computer.

2. Click on that icon to ____________ Internet Explorer.

3. I ____________ an important document, and now I can't find it.

4. You can access all the applications on your computer from the _________.

5. It's easy to move files into a folder. You can just ____________.

6. I asked the computer to ____________ for files with "English" in the name, but it didn't find any.

7. This is a shared computer. Each user has their own ____________.

8. You can free up space on your hard drive by ____________ applications you never use.

9. If you ____________ your photos as JPEGs instead of TIFFs, you'll use a lot less memory.

    drag and drop            installed         launch

    password                    renamed         save

    search                         uninstalling                 start menu

 

Task 9. Choose  the  correct  English  equivalents  for  the  Microsoft  Word

menu items .

1. сохранить как

A) keep as     B) protect as     C) save like             D) save as

2. править

A) edit            B) correct                C) check                 D) insert

3. вставить

A) include      B) paste                  C) add                     D) fill

4. параметры страницы

A) page setup B) page parameters C) page outline     D) page view

5. расстановка переносов

A) splitting     B) division               C) hyphenation      D) spelling

6. орфография

A) writing rules B) hyphenation      C) grammar            D) spelling

7. вырезать

A) delete        B) cut                       C) clear                   D) cancel

8. курсив

A) bold           B) italic                    C) font                     D) script

9. выделить все

A) choose all          B) outline all  C) select all             D) focus all

10. строка

A) sentence            B) line            C) phrase                D) passage

11. верхний индекс

A) top index            B) superscript C) top mark       D) high index

12. поля (страницы)

A) fields             B) areas         C) boundaries     D) margins

13. оглавление

A) contents             B) chapters   C) summary      D) list

14. нижний индекс

A) bottom index      B) subscript   C) bottom mark     D) low index

15. полужирный

A) bold           B) italic                    C) font                D) script

 

Task 10. Choose  the  correct  preposition.  Then  match  the  problem  with

the solution.

1. The operating system in / on       A. You can download one for

my computer doesn't support the              free to / from the internet.

latest version of / from this

application.

 

2. These files are too big.                 B. Perhaps you could get an

older version – or buy a new

computer!

3. My computer says it                                C. What about uninstalling the

hasn't got enough memory for /       driver for your old printer?

to run this program.

 

4. I can't understand this             D. Have you checked to see if

program. It's too complicated.           there are any updates available in / on the Internet?

 

5. I think there's a bug in /                 E. Why don't you close off / down

inside this software.                          all those other applications you've opened?

 

6. There doesn't seem to be an       F. You can get a manual. I've seen icon for the program in / on the            one in the local bookshop.

desktop.

 

7. I can't use this program. It's all     G. How about compressing

in / with French!                                          them with / by WinZip?

 

8. I can't get the driver for my           H. Go to / on the "start" menu, and

new printer to / at work.                     click at / on "All Programs".

 

9. I haven't got a media player in     I. Change the language

/ on my computer.                              setting.

Task 11. Choose the correct word to complete each sentence. You may change some words if necessary.

    apply, applicant, applicable, application

1. We have interviewed five ______ for the new position.

2. The last part of the form is not ______ to foreign students.

3. Office workers use many computer __________ such as word processing, spreadsheets, and databases.

4. When you ______ for a job, you may need to fill in a special form.

    identify, identical, identity, identification

5. For a long time, fingerprints have provided a method of reliable _______.

6. Most companies don’t allow people without an _______ card to enter their premises.

7. The program sends a packet with a source _______ to the destination, which causes many machines to lock up.

8. A password is used to _______ the computer-user and to allow access.

    explain, explanation, explanatory

9. The package includes an ______ booklet.

10. The instructions are very clear and do not require any further ______.

11. It will only take a couple of minutes to ______.how the program works.

Writing and Translation

Task 12. Read this passage, fill in the gaps using the words below, and translate into Russian.

The control panel

    The control panel provides options for ___(1)___ the appearance of your computer screen, ___(2)___ or removing programs and ___(3)___ network connections.

    When you get a new computer, perhaps the first thing you will want to do is set the date and time. You can also choose the ___(4)___ for dates and times. For example, November 5th 2010 can be ___(5)___ as

05-11-2010, 2010-11-05 or in various other formats.

    You may wish to change the desktop ___(6)___ to a picture, for example a personal photo taken on a ___(7)___ camera. A picture on the desktop background is also known as ___(8)___ .

    If a computer screen shows the same ___(9)___ for a very long time, it can leave a permanent impression. To avoid this, you can choose a ___(10)___ . This is usually a simple moving pattern which activates if the computer is not used for a set amount of time (for example, five minutes).

    You can also use the control panel to set up or change Internet and other network connections, including ___(11)___ network connections.

    In fact, you can change most aspects of your computer's ___(12)___ through the control panel, such as the system ___(13)___ , modem settings, scheduled ___(14)___ , although most users prefer to leave on the ___(15)___ settings rather than changing them.

    adding                     background                      customizing

    default                     digital                                displayed

    format                      image                               performance

    properties               screen saver                    setting up

    tasks                        wallpaper                         wireless

 

Task 13. Make the written translation into Russian (2,400 characters).

Information systems

    The objective of information systems is to provide information to all levels of management at the most relevant time, at an acceptable level of accuracy, and at an economical cost.

    Individual businesses require information according to the nature of their operations. A car manufacturer is particularly interested in the extent of competition from overseas manufacturers in the home market and competition from other home-based manufacturers. A tour operator is concerned about purchasing power and its effect on holiday bookings and the political situation prevailing in the various countries.

    As a general guide, the detail contained in reports containing information varies according to the position of the recipient in the hierarchical management structure. The chairman and managing director of a company require details of operations which are broad in scope and which concentrate on key factors pinpointing economic and financial trends.

    Functional management require information relating to the departments they are responsible for in sufficient detail to enable them to apply whatever measures are required to bring situations into line with requirements. They require information relating to events as they occur so that appropriate action can be taken to control them.

    Information systems are often computerized because of the need to respond quickly and flexibly to queries. At the bottom level in the information hierarchy are the transaction processing systems, which capture and process internal information, such as sales, production, and stock data. These produce the working documents of the business, such as invoices and statements. Typically, these are the first systems which a company will install. Above the transaction-level systems are the decision support systems. These take external information – market rends and other external financial data – and processed internal information, such as sales trends, to produce strategic plans, forecasts, and budgets. Often such systems are put together with PC spreadsheets and other unconnected tools. Management information systems lie at the top of the hierarchy of information needs. The MIS takes the plans and information from the transaction-level systems to monitor the performance of the business as a whole. This provides feedback to aid strategic planning, forecasting, and/ or budgeting, which in turn affects what happens at the transactional level.

 

Task 14. Match parts of the envelope with the headings .

The Marsdens

7425 (1) Lansdowne Road

(2) Bethesda, MD (3) 20812

Fred and Sylvia Becker
455 (4) Battery Lane
Bethesda, (5) MD 20814

A. Name of the state

B. Street name in the mailing address

C. Name of the city

D. ZIP code

E. Street name in the return address

Task 15. Read the document and fill in the gaps.

A) Re

B) From

C) Thank you

D) understand

 

___(1)____: Management

To         : Northwest Area Sales Staff

___(2)___: New Monthly Reporting System

We’d like to quickly go over some of the changes in the new monthly sales reporting system that we discussed at Monday’s special meeting. We ___(3)____ that you have concerns about the amount of time that will be initially required for inputting your client data. ___(4)___ all for your help in putting this new system into place.

 

Task 16. To which type is the document in Task 15 referred?

A) Application Letter

B) Contract

C) Memo

D) Letter of Enquiry

 

 

Task 17. Put the parts of the document into the correct order.

1) Dear Ms. Bragg,

2) Meridian National Bank,

12187, Polo Drive

Fairfax, VA, 22130

3) On behalf of Meridian National Bank I thank you for your ongoing business and trust that we will continue to serve you in the future.

4) Yours sincerely,

Brenda Wallis

Loans Manager

5) December 12, 2009

6) Suzanna Bragg

127 Polk Drive, No. 112

Gary, Indiana, 46402

7) After a thorough review of your application and the supporting documents you supplied, we have concluded that your current financial situation precludes this institution from extending further credit to you at this time. When your financial picture changes and your current level of risk-exposure becomes lower, we would be happy to reconsider your application.

 

 

Task 18. To which type of letter is the letter in Task 17 referred?

A) Application Letter

B) Rejection Letter

C) Letter of Credit

D) Letter of Enquiry

 

 



Speaking

Task 19. Make a list of software products you use (e.g. word processors, spreadsheets, media player, etc.). Then choose one product and comment on it. Are there any features you never use? Are there any features missing? Discuss it with your partner.


Task 20. Review crossword .

1 2
3
4 5
6
7
8 9
10

 

1. programs which tell the computer what to do (8)

2. a piece of software which makes a computer do a task (for example, edit an image) (11)

3. any set of instructions for a computer (7)

4. software which operates a peripheral, such as a scanner or printer (6)

5. application which stores and displays digital photos (5,5)

6. you enter a security code to prove that you have a _______ to use the software (7)

7. software which prevents unauthorized access to your computer over the Internet (8)

8. a series of letters and numbers which you have to enter before installing some programs (8,4)

9. download new features for an application (6)

10. an unauthorised copy of a program (7)

Task 21. Enjoy the jokes.

    Did you hear about the Microsoft Windows programmer who died? He found himself in front of a committee that decides whether one goes to Heaven or Hell. The committee told the programmer he had some say in the matter and asked him if he wanted to see Heaven and Hell before stating his preference. "Sure," he said, so an angel took him to a place with a sunny beach, volleyball, and rock and roll, where everyone was having a great time. "Wow!" he exclaimed. "Heaven is great!" "Wrong," said the angel. "That was Hell. Want to see Heaven?" "Sure!" So the angel took him to another place. Here a bunch of people were sitting in a park playing bingo and feeding pigeons. "This is Heaven?" asked the Windows programmer. "Yes," said the angel. "Then I'll take Hell." Instantly, he found himself plunged up to his neck in red-hot lava, with the hosts of the damned in torment around him. "Where's the beach? The music? The volleyball?" he screamed frantically to the angel. "That was the demo," she replied as she vanished.


Error Messages

  • "The world will end in 5 minutes. Please log out..."
  • "COFFEE.EXE missing. Insert cup and press any key."
  • "Bad Command or File Name. Good try, though."
  • "Press any key... no, no, no, NOT THAT ONE!"
  • "Enter any 11-digit prime number to continue..."
  • "General Failure's Fault. Not Yours."
  • "Hit any user to continue."
  • "Scandisk is now checking your hard disk. You can start praying."
  • "Smash forehead on keyboard to continue."
  • "Earth is 98% full. Please delete anyone you can."
  • "Cannot find REALITY.SYS...Universe Halted."
  • “Keyboard not found. Press any key to continue…”

Unit 4. Networks

Reading and Vocabulary

1) adjacent (A) – смежный, соседний

2) apparent ( A ) – явный, очевидный

3) bandwidth (N) – полоса пропускания, пропускная способность

4) connect (V) – соединять, connectivity (N) – связность

5) data link ( N ) – канал передачи данных, data link layer – канальный уровень

6) destination (N) – место назначения, получатель

7) distributed system – распределенная система

8) fiber optic (A) – оптоволоконный

9) frame (N) – кадр, фрейм

10) integrity (N) – целостность

11) interference ( N) – помеха

12) intricate ( A ) – сложный

13) layer (N) - уровень

14) loop (N) – цикл, петля

15) MAN [mæn] (Metropolitan-Area Network) – региональная сеть

16) medium (pl. media ) – среда (передачи данных)

17) NIC ( Network Interface Card ) – сетевая интерфейсная плата

18) OSI [ ΄ou ΄es ΄ai ] Reference Model – эталонная модель OSI

19) peer (N) ровня, peer-to-peer (A) – одноранговый

20) property ( N ) – собственность, proprietary ( A ) – патентованный

21) query (N) – запрос

22) recovery ( N ) – восстановление (после сбоя или ошибки)

23) route ( N , V )– маршрут, маршрутизировать, router [ ΄ru : t ə] ( N ) – маршрутизатор, routing (N) – маршрутизация

24) session (N) – сеанс (связи), session layer – сеансовый уровень

25) susceptible (A) – восприимчивый, чувствительный

26) subscriber ( N ) – абонент

27) share ( V ) – совместно использовать

28) stand - alone ( A ) – автономный, не входящий в систему

29) switch ( N ) – коммутатор; switched ( A ) – коммутируемый

30) terminate (V) – завершать, подключать (к линии связи)

31) token (N) – маркер (дающий право передачи)

32) UTP ( Unshielded Twisted Pair ) – неэкранированная витая пара

33) WAN [wæn] (Wide-Area Network) – глобальная сеть

Task 1. Complete the table with e xamples of networks below . Then add an example or your own to each column of the table.

Networks

Communications Utilities Transportation Biological Social
Cellular Fresh Water Air Traffic System Neurological Friends
         

 

Air Traffic System, Power Grid, TV/ Radio, Postal Service, Internet, Sewerage, Ecosystems, Family, Telephone, Cities, Highway System, LANs / WANs, Water Transport.

 

Task 2. Match the terms with their definitions.

1. Protocol              A) The process of finding a path to a destination host.

2. Synchronous      B) Various physical environments through which transmission signals pass.

3. Media                  C) The rated throughput capacity of a given network, medium, or protocol.

4. Broadcast           D) A set of rules and conventions that govern how devices on a network exchange information.

5. Bandwidth          E) Taking place at exactly the same time as something

6. Routing               F) Data packet that will be sent to all nodes on a network.

Task 3. Read the text and explain the meanings of the abbreviations.

1) LAN 2) MAN 3) WAN 4) ISDN 5) DSL 6) ATM 7) UTP 8) TCP /IP

Computer networks

1) A network is an intricately connected system of objects or people. Networks are all around us, even inside us. Your own nervous system and cardiovascular system are networks.

Computers and computer networks have changed the way we do almost everything – the way we teach, learn, do research, access or share information, communicate with each other, and even the way we entertain ourselves. A computer network consists of two or more computing devices (often called nodes) interconnected by means of some medium capable of transmitting data that allows the computers to communicate with each other in order to provide a variety of services to users.

2) In the very early days, computer networks were relatively small, and computer or modem vendors tended to develop proprietary protocols that allowed their machines to communicate with each other, but not necessarily with those made by others. This created the need to interconnect two or more compatible or incompatible networks together to create an Internet, or a network of networks. In the mid1970s, TCP/IP (Transmission Control Protocol/ Internet Protocol) was developed and became the main communication protocol. Today, TCP/IP is the defacto standard and is available for almost all computers. When sending a file from one machine to another, TCP breaks it into a number of data packets, which also include other information such as the type of packet, source, and destination addresses. IP then takes over, routing those packets from the source to the destination, where TCP takes over and reassembles them into the original file.

3) Networks that span a local area such as one or more neighboring buildings are called local-area networks, or LANs. Ethernet is by far the most widely used LAN technology today. LANs make it possible for businesses that use computer technology to share, efficiently, such items as files and printers, and to make possible communications such as e-mail.

As computer use in businesses grew, it soon became apparent that even LANs were not sufficient. In a LAN system, each department, or business was a kind of electronic island. What was needed was a way for information to move efficiently and quickly from one business to another. The solution was the creation of metropolitan-area networks (MANs) and wide-area networks (WANs). Generally, a MAN spans a larger geographic area than a LAN, but a smaller geographic area than a WAN. Because WANs connected user networks over a large geographical area, they made it possible for businesses to communicate with each other across great distances. As a result of being networked or connected, computers, printers, and other devices on a WAN could communicate with each other to share information and resources, as well as to access the Internet. Some common WAN technologies are: modems, ISDN (Integrated Services Digital Network), ADSL (Asymmetric Digital Subscriber Line), Frame Relay, ATM (Asynchronous Transfer Mode), The T (US) and E (Europe) Carrier Series: T1, E1, T3, E3, etc., SONET (Synchronous Optical Network)

LANs, MANs and WANs have always had one thing in common, though, and that is the use of the term bandwidth to describe their capabilities. Bandwidth is the measure of how much information can flow from one place to another in a given amount of time.

4) Client/server and peer-to-peer are phrases used to describe networks with different types of hierarchy and access control. Client/server computing describes distributed network systems in which transaction responsibilities are divided into two parts: client (front end) and server (back end). Peer-to-peer computing calls for each network device to run both client and server portions of an application.

During your study of networking, you will hear references to the word medium. (Note: The plural form of medium is media.) In networking, a medium is a material through which data packets travel. It could be any of the following materials:

· telephone wires

· Category 5 UTP (Unshielded Twisted Pair) (used for Ethernet)

· coaxial cables (used for cable TV)

· optical fibers (thin glass fibers that carry light)

· atmosphere (carries radio waves, microwaves, and light).

(From Cisco Networking Academy)

Task 4. Answer these questions about the text.

1) Using computers as stand-alone devices is ineffective for businesses, isn’t it? Why?

2) What does a data packet include?

3) What are LANs designed for?

4) What is the difference between client/server computing and peer-to-peer computing?

5) What are the media types used in networking?

 

Task 5. Decide  if  the  statement  is  true,  false  or  there  is  no information

in the text.

1) Computer networks appeared because people wanted something more quick and efficient than a conventional postal service.

2) TCP/IP was developed in 1980s.

3) A peer-to-peer network does not have any dedicated servers or hierarchy among its computers.

4) Routers make logical decisions regarding the best path for the delivery of data.

Task 6. Using the paragraph number references given, look back in the text and find words that have a similar meaning to.

1) environment (1)

2) sender address (2)

3) finding a path (2)

4) covers (3)

5) move (4)

 

Task 7. Choose the correct words.

1. ADSL is more commonly known as __________.

    A. longband            B. broadband         C. wideband

2. Broadband Internet connection is much faster than _________.

    A. dial-in                  B. dial-through        C. dial-up

3. Each time you want to connect to the network, you have to enter a log-in name and a __________.

    A. security word     B. safe word           C. password

4. With dial-up, you can usually choose a ________ tariff.

    A. pay-as-you-go   B. pay-what-you-want C. pay-if-you-like

5. Some broadband contracts limit the amount of _________ you can have each month.

    A. pages                 B. traffic                  C. use

6. Looking at web pages can be called "navigating the Web" but is more commonly called ________.

    A. "surfing the net" B. "skiing the net"   C. "swimming the net"

7. When your computer is not connected to the Internet, it is ________.

    A. out of line           B. offline                 C. off the line

8. An unexpected disconnection from the Internet is called a __________.

    A. lost connection  B. missed connection C. dropped connection

9. A file which is copied from the Internet onto your computer is called _____.

    A. an upload           B. a download        C. a load

10. The word “blog” which means “online journal” originates from _______.

    A. “block”           B. “web log”            C. “best log”

11. The word “spam” originates from _________.

    A. “spice and ham” B. “spend and have” C. “spoiled ham”

 

Task 8. Match the network topologies with their descriptions .

    Bus / Ethernet       Star      Switched      Ring

1) In this configuration, the central computer performs all processing and control functions. All access devices are linked directly to the central computer. The configuration has two major limitations. First of all, the remote devices are unable to communicate directly. Instead, they must communicate via the central computer only. Secondly, the network is very susceptible to failure, either in the central computer or the transmission links.

2) The central device, which could be a telephone exchange, is used to connect different devices on the network directly. Once the link is established, the two devices communicate as though they were directly linked without interference from any other device. At the end of the session, the connection is closed, freeing capacity for other users and allowing access to other devices. Multiple switches can be used to create alternative transmission routes.

3) Each device is attached to a network shaped as a continuous loop. Data proceeds in only one direction and at a constant speed round the loop. Devices may send information only when they are in control of the 'token'. The token is a package of data which indicates which device has control. The receiving device picks up the token, then clears it for another's use once it has received the message. Only one device may send data at any given moment, and each device must be working for the network to function.

4) This network consists of one piece of cable terminated at each end to which all devices are connected. In such a network, each device is able to broadcast a message when it has detected silence for a fixed period of time. All devices receive the broadcast and determine from the content of the message whether it was intended for them. The only problem occurs when two devices try to send at the same time. When a sending device detects another's transmission, it aborts its own.

 

Task 9. Read the text and choose the correct words.


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