Text 6 «Packet switching».
PACKET SWITCHING
Refers to protocols in which messages are divided into packets before they are sent. Each packet is then transmitted individually and can even follow different routes to its destination. Once all the packets forming a message arrive at the destination, they are recompiled into the original message.
Most modern Wide Area Network (WAN) protocols, including TCP/IP, X.25, and Frame Relay, are based on packet-switching technologies. In contrast, normal telephone service is based on a circuit-switching technology, in which a dedicated line is allocated for transmission between two parties. Circuit-switching is ideal when data must be transmitted quickly and must arrive in the same order in which it's sent. This is the case with most real-time data, such as live audio and video. Packet switching is more efficient and robust for data that can withstand some delays in transmission, such as e-mail messages and Web pages.
A new technology, ATM, attempts to combine the best of both worlds -- the guaranteed delivery of circuit-switched networks and the robustness and efficiency of packet-switching networks.
How do messages get transmitted with the help of packet switching technologies?
How do packet-switching and circuit-switching technologies differ? What are they used for?
Text 7 «ATM»
ATM
Short for Asynchronous Transfer Mode, a network technology based on transferring data in cells or packets of a fixed size. The cell used with ATM is relatively small compared to units used with older technologies. The small, constant cell size allows ATM equipment to transmit video, audio, and computer data over the same network, and assure that no single type of data hogs the line.
Some people think that ATM holds the answer to the Internet bandwidth problem, but others are skeptical. ATM creates a fixed channel, or route, between two points whenever data transfer begins. This differs from TCP/IP, in which messages are divided into packets and each packet can take a different route from source to destination. This difference makes it easier to track and bill data usage across an ATM network, but it makes it less adaptable to sudden surges in network traffic.
In what ways is ATM similar to and different from the transmission technologies mentioned above?
What are the advantages and disadvantages of ATM?
Text 8.
1. Skim the text. Decide on the title. (Просмотрите текст. Выберите подходящий заголовок для текста).
- COMPUTER FUNCTIONS
- MODERN ACCOUNTING FIRMS
- THE USE OF COMPUTERS IN ACCOUNTING
A computer like any other machine is used because 1) _____________________. It can receive more information and process it faster than any human. The speed at which a computer works means it can replace weeks or even months of pencil-and-paper work. Therefore computers are used when the time saved offsets their cost which is one of the many reasons 2) ____________________.
Modern accounting firms use spreadsheet software to do complicated calculations. They can provide their сlients with an up-to-date report 3)_____________________. This software has many functions and can be integrated with other software. The spreadsheet's basic component is a cell. This may contain a formula 4) _________________________. It could also contain a label or data. The former describes the information on the worksheet. The latter is the information itself.
The worksheet is the basic work area of a spreadsheet program. It is made up of cells arranged in rows and columns. The number of these varies depending on the software you are using. You can change the width and format of cells. Such parameters are usually quite easy 5) ______________________.
2. Complete the sentences with the appropriate endings. (Подберите соответствующие окончания для предложений в тексте):
a) whenever it is needed
b) which performs a mathematical operation
c) to change with just a few keystrokes.
d) it does certain jobs better and more efficiently than humans.
e) they are used so much in business, industry, and research.
3. Write antonyms for the words (Подберите антонимы к словам):
1. the former 5. up-to-date
2. efficient 6. better
3. fast 7. a few
4. easy
4. Using the vocabulary of the text, translate the sentences into English. (Переведите предложения на английский язык, используя лексику текста):
1. Компьютеры обрабатывают данные быстрее и эффективнее, чем человек.
2. Компьютеры используют в промышленности, если выигрыш по времени превышает денежные затраты на их обслуживание.
3. Скорость работы компьютера позволяет выполнить за час недельный объем бумажной работы.
4. Основным элементом крупноформатной электронной таблицы является ячейка.
Grammar Focus
5. Put the words in brackets into the correct form. (Употребите прилагательные в скобках в правильной форме):
1. The computer does certain jobs (good) and (efficiently) than humans.
2. It can calculate much (fast) than any human.
3. IBM PCs are (expensive) than their Apple counterparts.
4. This spreadsheet is (complicated) program of all I’ve ever worked with.
5. Accountants’ work has become far (easy) with the invention of calculator.