Hard disc

Hard discs were invented in the 1950s. They started as large discs up to 20 inches in diameter holding just a few megabytes. They were originally called “fixed discs” or “Winchesters”. They later became known as “hard discs” to distinguish them from “floppy discs”. Hard discs have a hard platter that holds the magnetic medium, as opposed to the flexible plastic film found in tapes and floppies.

A typical desktop machine has a hard disc with capacity of between 60 and 400 gigabytes. Data is stored onto the disc in the form of files. A file is simply a named collection of bytes. The bytes might be codes for the characters of a text file, or they could be instructions of a software application for the computer to execute, or they could be the records of a data base, or they could be the pixel colors for a GIF image. No matter what it contains, however, a file is simply a string of bytes. When a program running on the computer requests a file, the hard disc retrieves its bytes and sends them to the CPU one at a time.

A hard disc itself is a sealed aluminum box with controller electronics attached to one side. The electronics control the read/write mechanism and the motor that spins the platters. The electronics also assemble the magnetic domains on the drive into bytes (reading) and turn bytes into magnetic domains (writing).The electronics are all contained on a small board that detaches from the rest of the drive. Underneath the board are the connections for the motor that spins the platters, as well as highly-filtered vent hole that lets internal and external air pressure equalize.

Removing the cover from the drive reveals an extremely simple but very precise interior: the platters which are manufactured to amazing tolerances and are mirror-smooth and the arm that holds the read/write heads. It is controlled by the mechanism in the upper-left corner and is able to move the heads from the hub to the edge of the drive.

Data is stored on the surface of a platter in sectors and tracks. Tracks are concentric circles, and sectors are pie-shaped wedges on a track. A sector contains a fixed number of bytes. Either at the drive or the operation system level, sectors are often grouped together into clusters.

Hard disc has got some benefits – you can move to any point on the surface of the disc almost instantly; the information can be easily erased and rewritten, and it will “remember” the magnetic flux patterns stored onto the medium for many years.

IX. Say “true” or “false”. Correct the “false” sentences:

1. Removable storage appeared later than computer.

2. Removable storage has only one advantage.

3. Removable storage devices can be of three categories.

4. The most convenient is a floppy disc.

5. Hard disc consists of several floppy films.

6. File is a string of letters and numbers.

7. A hard disc is a sealed box controlled by electronics.

8. Data is stored in sectors and tracks.

UNIT 7 “Optical auxiliary storage devices”

I. Read and guess the meaning of the following international words:

Compact, design, spiral, laser, micron, focus, polycarbonate, aluminum, organic, temperature, mixture, crystallize, multimedia, version, identical, physical, parameter.

II. Memorize the following “false friends”:

Momentum – импульс, толчок

III. Translate the following sentences into Russian. Pay attention to the modal verbs:

1. Heat is a form of energy and may be measured in the units in which energy is measured. 2. We must say that the discovery of atomic energy is as important as the discovery of fire. 3. Electronic machines can add, subtract, multiply and divide much quicker than man. 4. The origin of automation can be traced back to the early days of the first industrial revolution. 5. She may use different methods in her research work. 6. For a long time scientists could not discover the secret of the atom. 7. This equipment can work with high accuracy. 8. You may use these devices in your research work. 9. The atom is a great force that must be used for the good of mankind. 10. Chemists must create the materials which don't exist in nature. 11. Naturally, this circuit can be modified if necessary. 12. This kind of energy must find application in transport.

IV. Choose the sentences where the verbs to have and to be are used in the functions of Modal Verbs and translate them:

1. These devices have been used in our experiment. 2. Scientists have to work hard to create a new atomic technique. 3. A modern computer has two main parts: a memory and a computing unit. 4. As the known resources of coal and oil are limited, man has to find new sources of power. 5. Very difficult calculations in mathematics and elect­rical engineering have to be solved by computers. 6. People of good will have to struggle for peaceful use of atomic energy. 7. When tech­nique reaches a very high stage of development, new methods of work will be possible. 8. We are to take into consideration all the advantages and disadvantages of this device for the future work. 9. We are to take special steps to reduce the weight of this mechanical part. 10. These new data are obtained after our experiment. 11. At present our engineers are to develop the most advanced methods of production. 12. Our design bureau has to construct a new adding machine. 13. This device has been used in our experiment. 14. The experts are to inspect this plant.

V. Translate the sentences into Russian. Pay attention to the use of Modal Verbs and their Equivalents:

1. Without a computer scientists will not be able to solve compli­cated problems. 2. Modern computers can multiply two numbers in a microsecond. 3. This machine can do the work of hundreds of work­ers. 3. He has to finish his experiment in time. 4. She was allowed to carry out this research as she had taken part in the scientific sym­posium. 5. Every student must know the difference between automation and mechanization. 6. With the help of radioactive elements we were able to measure the thickness of various materials. 7. Every engineer must improve his technical knowledge. 8. Scientists of different count­ries must cooperate in their research and peaceful application of their discoveries. 9. In fact, there is hardly any sphere of life where the atom may not find useful application. 10. The computer can perform different mathematical operations. 11. Our plant is to increase its output. 12. Every plant must fulfill its plan in time. 13. Workers must apply new methods of production.

VI. Translate the following sentences into Russian paying attention to Modal Verbs with Perfect Infinitive:

1. The engineer might have overlooked something that may turn out to be important in carrying out this experiment. 2. All the prepara­tions must have been completed long ago. 3. Some day atomic energy might have been used to control the weather of the world. 4. He may have got the condenser he needed for his experiment. 5. He cannot have broken the tube while making this experiment. 6. You should have changed the current strength at all points of the circuit. 7. He may have got the article he needed. 8. You should have helped your friend.

VII. Read the words and word combinations and memorize their meaning:

to be familiar with – быть знакомым, знать

bump – углубление

injection-molded – литой

tricky – искусный, сложный

to dye – окрашивать

antimony- сурьма

compound – смесь

versatile – универсальный, многоцелевой

to gather momentum – приобретать движущую силу

revenue – доходный

shot run – короткий период, небольшая партия изделий, малый тираж

standalone – автономный

backwards – имеющий отношение к прошлому

compatibility – совместимость

outset – начало

add-on – добавленный для расширения

UDF – (User-Defined Function) функция, определяемая пользователем

bond – связывать, соединять

substrate – подложка, основание печатной платы