Types of Computer Networks Local Area Networks

Просмотрите текст и выполните следующие задания.

I. Используя специализированный англо-русский словарь по вычислительной технике, переведите следующие слова и словосочетания и запомните их:

local area network

software package

network cable

cable interface unit

box

network interface card

expansion slot

gateway

II. Переведите следующие именные группы, обращая внимание на перевод слов в функции определения:

data resource; hardware device; hardware component; different data formats

III. Назовите приставки в следующих словах. Переведите слова на русский язык:

dissimilar, disability, disconnect, disengage, inability, inaccurate, imbalance, irrelevant, irregular, uncontrollable, to unlink, unreadable

IV. Переведите следующие сказуемые в страдательном залоге вместе с относящимися к ним подлежащими. Обратите внимание на время сказуемого:

each hardware device is called; the package is designed and licensed; the card is connected; the network interface card is inserted

V. Выпишите из пятого абзаца сказуемое в страдательном залоге, в составе которого есть модальный глагол, и переведите его вместе с подлежащим.

VI. Проанализируйте следующее предложение и переведите его на русский язык, предварительно определив функцию инфинитива и уточнив в словаре значение союза "as long as":

Because the computers in a LAN share software, one copy of a software package is needed, as long as that package is designed and licensed to be used on a network.

VII. Переведите следующие предложения, обращая внимание на инфинитив:

1. To program in a good way the programmer needs detailed data about the program and the way it is to be done.

2. To study basic stages of programming is the aim of our seminar.

3. Some computers were built to understand the spoken word and to read the printed material.

4. To be familiar with the structure of the program and the possibilities it offers is very important.

VIII. Переведите текст с учетом выполненных заданий. Второй и пятый абзацы переведите письменно.

1. A local area network (LAN) uses direct, high-speed cables to share hardware, software, and data resources. With a LAN, the connection spans short distance and doesn't use wires owned by a telephone company. Typically, a LAN connects the computers in a department, a building, or several buildings situated near each other. Each hardware device on a LAN such as a computer or printer, is called a node. A LAN integrates anywhere from two or three computers up to several hundred computers.

2. The capability of sharing resources is a major advantage of a LAN. Because the computers in a LAN share hardware, several people can use the same network printer. Because the computers in a LAN share software, only one copy of a software package is needed, as long as that package is designed and licensed to be used on a network. Sharing data means that all the LAN users can access one database and get the most up-to-date data.

LAN Hardware

3. In addition to computers, the hardware components needed to create a LAN include the network cable, a cable interface unit, and network interface cards for each computer. The network cable can be twisted-pair cable, coaxial cable, or fiber optic cable. The cable interface unit, sometimes called a hub, sends and receives signals on the network cable. This unit is a box outside the computer.

4. The network interface card is inserted into an expansion slot inside the computer. The interface card sends and receives messages to and from the LAN. The card is connected to the cable interface unit by wire.

5. LANs can be connected by a bridge, a router, or a gateway. If two LANs are similar you use a bridge to connect them. With two or more similar LANs, you use a router to connect them. With two dissimilar LANs, you use a gateway. The gateway translates the LANs' different data formats.

IX. Составьте аннотацию текста.

Text 8

LAN Topology. LAN Models

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star topology

ring topology

bus topology

host computer

peer-to-peer network

to run the program (the network)

public file

II. Переведите следующие именные группы, обращая внимание на перевод слов в функции определения:

a large hard disk capacity; the network operating system; large data files; the network management task

III. Выпишите из текста интернациональные слова, проверьте их перевод и произношение по словарю.

IV. Используя обычный англо-русский словарь, переведите следующие выражения:

regardless of the topology; to follow one of two models; to be in charge of the network; to make available for others to access; to fail: the computer fails.

V. Из второго абзаца выпишите предложение с глаголом "to do", определите его функцию и переведите предложение на русский язык.

VI. Выпишите из третьего абзаца союзы и союзные слова, присоединяющие придаточные предложения к основным, и переведите их.

VII. Выпишите из седьмого абзаца предложение, в котором "one" выполняет функцию слова-заместителя. Переведите предложение на русский язык.

VIII. В следующем предложении определите группу подлежащего, укажите, чем она выражена. Переведите предложение на русский язык:

… and keeping track of the information on each computer can be difficult.

IX. Переведите текст с учетом выполненных заданий. Второй, третий и седьмой абзацы переведите письменно.

LAN Topology

1. The physical layout of a local area network is called its topology. The three most common topologies for LANs are star, ring, and bus.

2. A star topology has a host computer, which is responsible for managing the network. Usually, a database and printer are part of this host computer. The other nodes are attached to the host and all messages are routed through the host. If the central computer fails, so does the network.

Types of Computer Networks Local Area Networks - student2.ru

3. A ring topology has all nodes attached in a circle, without a central host computer. Messages travel around the ring until they reach the computer to which they are addressed. If the ring is broken, the network fails.

Types of Computer Networks Local Area Networks - student2.ru

4. A bus topology does not use a central or host computer. Instead, each node manages part of the network. Information can be transmitted from one computer directly to another without travelling through every other node. Bus topology is the most popular LAN topology because the failure of one network computer does not affect the other network computers.

Types of Computer Networks Local Area Networks - student2.ru

LAN Models

5. Regardless of the topology, LANs usually follow one of two models: client / server or peer-to-peer.

6. A client / server model uses one or more computers as servers, and the other computers on the network are clients. The server is a high-capacity, high-speed computer with a large hard disk capacity. It contains the network operating system, the software required to run the network. The server also contains network versions of programs and large data files. Clients — all the computers that can access the server — send request to the server. Here are some common services that clients request:

● Storing and retrieving files on the server's hard disk

● Running programs that are stored on the server's hard disk

● Printing to a network printer

The client / server model works with any size or topology of LAN.

7. With the peer-to-peer model, all computers on the network can access public files and printers connected to other computers in the network. (A public file is one that a user has made available for other to access.) No one computer is in charge of the network; all computers share the network management tasks. A peer-to-peer network tends to slow down with heavy use, and keeping track of the information on each computer can be difficult. Therefore, this model is used with small networks. A network can also be a hybrid combining elements of both client / server and peer-to-peer models.

X. Составьте аннотацию текста.

Text 9

The Impact of LANs

Просмотрите текст и выполните следующие задания.

mainframe

input / output devices

keyboard

data processing department

maintenance (computer maintenance)

backup (data backup)

to keep track

II. Выпишите из четвертого абзаца именные группы и переведите их.

III. Проанализируйте состав слова "knowledgeable".

IV. Переведите следующие слова, не пользуясь словарем:

1. readable; accessible; programmable; controllable; manageable;

2. oversized; overload; to overwork; overtesting; overdesign

V. Выпишите из обычного англо-русского словаря значения слова "responsibility" и переведите следующие предложения:

1. The maintenance of the computer was the responsibility of the data processing department.

2. Many companies are changing the storage of and the responsibilities for their data.

VI. Найдите в четвертом абзаце слово, которое относится к "ложным друзьям" переводчика. Выпишите в словарь правильное значение этого слова.

VII. Переведите на русский язык следующие сочетания модального глагола "must" с инфинитивом в страдательном залоге:

must be provided; must be changed; must be controlled; must be replaced

VIII. Определите функцию инфинитива в следующих предложениях и переведите предложения на русский язык:

1. The mainframe computer required experts to maintain it.

2. Like mainframes, LANs require a knowledgeable person to keep them working.

IX. Проверьте по англо-русскому словарю значения "as" и запишите их в свои словари.

X. Проанализируйте следующие предложения и переведите их на русский язык:

1. Mainframes and minicomputers became more powerful, and new databases that were created grew to be very large.

2. As a company grows, adding new computers to the LAN is easier than adding new terminals to an overworked mainframe or minicomputer.

XI. Переведите текст с учетом выполненных заданий. Третий абзац переведите письменно.

The Impacts of LANs

1. As the use of computers increased during the 1960s and 1970s, the value of information became more obvious to businesses and other computer users. Mainframes and minicomputers became more powerful, and new databases that were created grew to be very large. The department that was responsible for maintaining the data in a database wanted to be able to access the data quickly at any time. Users began to demand more control over the database. The mainframe computer, however, still required experts to maintain it, and most of these experts worked in the data processing department.

2. The solution was to add terminals, input / output devices consisting of a keyboard and a monitor. Users could access the data through their terminals, but the maintenance of the computer was the responsibility of the data processing department. Because the data processing department continued to control the data, hardware, and software, other departments using the data found that changing hardware or software could be cumbersome and slow. This difficulty created real problems for these departments.

3. Today, many companies are changing the storage of and the responsibilities for their data. A LAN, with data distributed among the responsible departments, is less expensive than a mainframe computer. The necessary software is often easier to use than the software for the mainframe and can be readily upgraded or changed. As a company grows, adding new computers to the LAN is easier than adding new terminals to an overworked mainframe or minicomputer.

4. In some ways, maintaining a LAN is similar to maintaining a mainframe. Like mainframes, LANs require a knowledgeable person to keep them working. Both mainframes and LANs require periodic backups of the data and the software in case of a disk failure. Procedures to back up and recover data must be provided for both LANs and mainframes. Though networks have already replaced many mainframe and minicomputer installations, powerful mainframes are still needed for huge tasks, such as keeping track of airline reservations. There is, however, no doubt that LANs have dramatically changed the nature of data processing.

XII. Составьте аннотацию текста.

XIII. Подготовьте устное сообщение о локальных сетях.

Text 10

Wide Area Networks

Просмотрите текст и выполните следующие задания.

dedicated line

to condition

conditioned line

leased line

relay tower

microwave

line-of-sight

II. Выпишите из четвертого и пятого абзацев именные группы и переведите их.

III. Найдите в четвертом абзаце слово с отрицательной приставкой и переведите его.

IV. Назовите интернациональные слова, которые встречаются в тексте.

V. Используя обычный англо-русский словарь, переведите выражение "to get in the way" и запомните его.

VI. Выпишите из текста сказуемые в страдательном залоге и переведите их вместе с подлежащими.

VII. Проанализируйте и переведите на русский язык следующее предложение:

The chief disadvantage of microwaves is they depend on line-of-sight transmission.

VIII. Выпишите из третьего и четвертого абзацев причастия, определите их форму и функцию и переведите их на русский язык вместе с относящимися к ним словами.

IX. Проанализируйте глагольные формы с окончанием -ed в следующих предложениях. Переведите предложения на русский язык:

1. He described the method used by this engineer.

2. The engineer used the method described in this book.

3. The programming languages discussed attracted the attention of many users.

4. The results obtained changed the entire nature.

5. None of the scientists involved based his experiment on this method.

X. Переведите текст с учетом выполненных заданий.

Types of Computer Networks Local Area Networks - student2.ru Wide Area Networks

1. A wide area network (WAN) is a computer network that directly connects computers separated by long distance — more than a mile and as much as half the globe. WANs require special media, which are provided by telephone companies and other firms that specialize in this service. WANs also require special hardware.

Physical Media for WANs

3. Wide area networks use special-purpose telephone wires, fiber-optic cables, microwaves, or satellites for communications.

4. The simplest WANs use dedicated lines. A dedicated line is a specially conditioned telephone line that directly and permanently connects two computers. Dedicated lines provided by telephone companies are called private lines, or leased lines. A leased line can handle as much as 64,000 bites per second. Some special-purpose dedicated lines can handle as much as 64 million bits per second.

5. Microwaves, as mentioned earlier, are radio waves that have a very high frequency. Besides warming your pizza, they can transmit data. The chief disadvantage of microwaves id they depend on line-of-sight transmission. No obstruction can get in the way. Furthermore, microwaves can travel only about 50 miles. For both of these reasons, some networks build microwave relay towers.

6. Communications satellites are placed in a geosynchronous orbit thousands of miles above the earth. In this orbit, the satellite rotates with the earth so that it is always above a given spot. The latest WANs use long-distance fiber optic cables.

XI. Составьте аннотацию текста.

Text 11

WAN Service Providers

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service provider

common carrier

dedicated Integrated Services Digital Network

value-added network

public data network

data highway (high-speed data highway)

item

multiplexor

unauthorized access

front-end processor

II. Проанализируйте состав слова "usefulness".

III. Используя обычный англо-русский словарь, переведите на русский язык выражение "to get bogged down" и запомните его.

IV. Определите функцию инфинитива в следующем предложении. Переведите предложение на русский язык:

A tariff is a list of services and charges for the services to be offered.

V. Выпишите из первого и четвертого абзацев причастия, определите их форму и функцию и переведите вместе с относящимися к ним словами.

VI. Переведите следующие предложения, обращая внимание на перевод причастия в зависимости от его формы и функции:

1. Architecture including all levels of hardware design is one of the major subdisciplines of computer science.

2. Being equipped with special conversion devices, the hybrid computer utilizes both analog and discrete representation of data.

3. Howard Aiken completed a fully automatic calculator in 1944 using standard machine components.

4. Using the very limited capabilities possessed by all computers, various tasks can be done quite easily.

5. Being based on packet-switching, Asynchronous Transfer Mode was designed with an entirely different approach — cell switching.

6. The data being transmitted from one teletype terminal to another was of great importance.

VII. Помните, что Past Participle может употребляться в причастных оборотах для выражения обстоятельства причины. Такие обороты соответствуют придаточным предложениям причины с глаголом-сказуемым в страдательном залоге.
Проанализируйте и переведите следующее предложение из шестого абзаца:

Based on routing data kept in an automatically updated table, the router decides where to send each packet.

VIII. На что указывает "would"в первом предложении седьмого абзаца?

IX. Переведите текст с учетом выполненных заданий, второй и седьмой абзацы переведите письменно.

WAN Service Providers

1. Dedicated lines, microwave communications, and satellite services are available from a variety of companies, including the common carriers. Increasingly, telephone companies are offering dedicated Integrated Services Digital Network (ISDN) connections to businesses and large organizations.

2. When an organization wants to offer communications services to others, it submits a tariff to the government. (A tariff is a list of services and charges for the services to be offered.) When the government has accepted the tariff and approved the organization to offer communications to others, that organization is known as a common carrier.

3. Some firms specialize in providing dedicated lines. These companies lease dedicated lines, add services to enhance the communications, and then sell that enhanced service. This service is called a value-added network.

4. A public data network (PDN) builds its own high-speed data highways using microwaves, satellites, and optical fiber. A PDN can send data at rates of one million bits per second or more.

WAN Hardware

5. WANs require some special hardware items. A multiplexor is a hardware device that enhances the usefulness of a WAN connection. A multiplexor combines input signals from as many as several dozen computers and sends the combined signal along the communications channel. On the other end, an identical multiplexor decodes the signal and sends the messages to their correct destinations.

6. Routers work with packet switching networks. They receive packets and examine their addresses. Based on routing data kept in an automatically update table, the router decides where to send each packet.

7. Front-end processors handle all the communications tasks for large computers, which would otherwise get bogged down by sending and receiving messages. These processors also provide security to prevent unauthorized access.

X. Составьте аннотацию текста.

XI. Подготовьте устное сообщение о глобальных сетях.

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