Upload Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
Экзамен.тексты ДФО.doc
197.12 Кб
  1. Analyze grammar in the underlined words and word combinations (in writing).

  1. Make up 5 questions of different types to the text (in writing). Text 21

1. Read and translate the text in writing.

The earliest forms of telegraphy were probably smoke, fire, or drum signals. In the late 18th century optical telegraphs were invented by Claude Chappe in France and by George Murray in England. Called semaphores, these telegraphs relayed messages from hilltop to hilltop with the aid of telescopes. Chappe's system used a vertical timber holding a movable crossbar with indicators at each end that could assume various configurations, like a signalman with flags. Murray's system used a large tower-mounted box with six panels that opened and closed in different combinations according to a code. Rapid development of telegraph systems came with the discovery that electric impulses could be used to transmit signals along a wire. Among the many electric systems attempted was the needle telegraph, based on Hans Christian Orsted's discovery in 1819 that an electric current caused an adjacent magnetized needle or pointer to deflect. The Cooke and Wheatstone five-needle telegraph of 1837 utilized this phenomenon with a panel imprinted with letters and numerals to which the five needles pointed singly or in pairs. This apparatus was widely used in Great Britain, especially for railroad signaling.The development of the electromagnet about that time provided the American inventor Samuel Morse with a way to transmit and receive electric signals. Together with Alfred Vail, his partner from 1837, Morse developed the simple operator key, something like a single typewriter key, which when depressed completed an electric circuit and sent a signal to a distant receiver, which was originally a device that embossed a series of dots and dashes on a paper roll. The use of dots and dashes to represent letters, numbers, and operating functions became known as the Morse Code. About 1856 a sounding key was developed; skilled operators could listen to what the key “said” and write the messages directly, or, after 1878, type them.

  1. Analyze grammar in the underlined words and word combinations (in writing).

  1. Make up 5 questions of different types to the text (in writing). Text 22

1. Read and translate the text in writing.

Computer Viruses

Computer viruses are harmful computer programs that can destroy information on a computer or cause the computer to stop. Today we tell about a recent virus attack and how you can protect your computer from such attacks.

The Internet communications system permits millions of computer users around the world to link together for business and enjoyment. Private Citizens, businesses and governments use the Internet. Anyone using the Internet can find information about many different subjects in many different languages in only a few minutes.

The Internet is the fastest, most modern and best communications tool ever invented. However, the Internet also makes it possible for one person to damage or slow thousands of computers that are linked to it. They can do this by writing computer instructions that cause damage. Or they make the computer fill itself with so much useless information that it stops working.

On January twenty-fourth, a kind of computer virus called a “worm” was released to infect the Internet. A worm is a computer instruction that makes copies of itself and sends copies to other computers.

This worm sent copies of itself to computers across the Internet. The worm temporarily damaged millions of computers around the world. It slowed large groups of computers called networks. For example, one large American banking company had to close about thirteen-thousand of its money machines. People could no longer get their money from the bank’s machines using their plastic cards.

A major international airline could not sell tickets using the Internet because the worm made its computers fail. Emergency service workers in the western American City of Seattle, Washington could not answer emergency calls because the worm caused their computers to fail.

Computer experts named the worm “W-Thirty-Two-Slammer.” They said the worm caused a problem for the Internet that was similar to when there are too many cars on a road in a large city. This kind of vehicle problem is called a traffic jam. The Slammer worm caused an information jam.

Тут вы можете оставить комментарий к выбранному абзацу или сообщить об ошибке.

Оставленные комментарии видны всем.