Compact disc

1. A compact disc(or CD ) is an optical disc used for storing digital data. It was originally invented for digital audio and is also used as a data storage device, a CD-ROM. CD-ROM reading device is a standard component of most modern personal computers. In general, audio CDs are distinct from CD-ROMs, and CD players intended for listening to audio cannot make sense of the data on a CD-ROM, though personal computers can generally play audio CDs. It is possible to produce composite CDs containing both data and audio with the latter capable of being played on a CD player, whilst data or perhaps video can be viewed on a computer. Lately, with the advent of MP3 technology, audio player devices have been developed that can load and play MP3-formatted files from CD-ROM discs. The advantage of MP3 is that it reduces the amount of space required to store audio by around ten times, thereby increasing maximum playback time per disc from around 74 minutes to more than 700 without significant degradation in sound quality.

2.The compact disc was developed in 1979 by Philips and Sony. Philips invented the general manufacturing process, based on their earlier Laserdisc technology, while Sony contributed the error-correction method. 1982 saw its mass production in Langenhagen near Hanover, Germany. Microsoft and Apple Computer were early enthusiasts and promoters of CD-ROMs. John Sculley. CEO of Apple at the time, said as early as 1987 that the CD-ROM would revolutionize the use of personal computers.

Originally the CD was supposed to be 60 minutes, but Sony insisted on it being 74 minutes so it could hold even the slowest versions of Beethoven's 9th Symphony. Later on, the discs would become larger, tough.

3. Compact discs are made from a 1.2 mm thick disc of polycarbonate plastic coated with a much thinner aluminium (originally gold, although you can still buy gold CDs for their data longevity) layer which is protected by a film of lacquer. The lacquer can be printed with a label. Common printing methods for compact discs are silkscreening and offset printing. CDs arc available in a range of sizes but the most commonly available is 120 mm (about 5 inches) in diameter. A 120 mm disc can store about 74 minutes of music or about 650 megabytes of data. Discs that can store about 700 megabytes (80 minutes of music) have become more common however. Less common 90, 99, and 100 minute discs also exist but are not compatible with all CD writers or readers. The mini-CD (not to be confused with the similar MiniDisc) is 80 mm (about 3 1/8 inches) in diameter, holds about 184MB of data or 21 minutes of audio, and has the exact same data format as the larger one. Yet another version of the CD has a mini-CD trimmed down to fit in with business cards.

4. The data format of the disc, known as the “Red Book” standard, was laid out by the Dutch electronics company Philips, who own the rights to the licensing of the “CDDA” logo that appears on the disc. In broad terms the format is a two-channel (left and right, for stereo) 16-bit PCM encoding at a 44.1 kHz sampling rate. Reed-Solomon error correction allows the CD to be scratched (to a certain degree) without degradation of the contents.

VI. Say if the following statements are true or false. Correct the false statements.

1. Personal computers can’t play audio CD.

2. There are many advantages of MP3 technology.

3. Microsoft was the pioneer in the usage of CD-ROMs.

4. First disks were large and tough.

5. The producers protect CD by a film of lacquer.

6. Mini-CD holds 80 minutes of audio.

VII. Choose the best continuation for each of the following.

1. Compact disk was invented for a. a personal computer

2. CD-ROM is a part of b. 1979

3. The first CD was developed in c. thin aluminium

4. The mini CD has the same data format d. digital devises

5. CD is coated with e. 700 megabytes

6. CD can store f. as the larger

VIII. Divide the text into logical parts and find the topical sentences in each

part.

IX. Give a short summary of text B.

Part C

I. Read the following text and entitle it.

1. Despite the importance of these other types of electronic devices, semiconductor-based circuits are the essential features of modern electronic equipment. These circuits are not made up of individual, separated components as was once the case. Instead, thousands of tiny circuits are embedded in a single complex piece of silicon and other materials called an integrated circuit (IC).

2. The manufacture of integrated circuits begins with a simple circular wafer of silicon a few inches across. Designers have produced drawings of exactly where each element in the finished circuits is to go. Usually these diagrams are themselves made with the help of computers. Photographs of the diagrams are then reduced in size many times to produce a photolithographic mask. The wafers are first coated with a material called a photoresist that undergoes a chemical change when exposed to light. Light shone through the mask onto the photo resist creates the same pattern on the wafer as that on the mask. Solvents then etch away the parts of the resist exposed to light, leaving the other parts intact.

3. After this another layer of material—for example, silicon doped with some impurities—is laid down on top of the wafer, and another pattern is etched in by the same technique. The result of several such operations is a multilayered circuit, with thousands of tiny transistors, resistors, and conductors created in the wafer.The wafer is then broken apart along pre-stressed lines into dozens of identical square or rectangular chips—the finished integrated circuits.

4. During the 1970s and 1980s advancing technology reduced the size of individual circuit elements by a factor of two every two years, leading in the same period to a fourfold increase in the number of elements that can fit on a chip. This rapid increase in the power of the chips and the simultaneous rise in their speed allowed the development of microprocessors. Microprocessors, which are at the heart of millions of personal and home computers, pack the same computing power into a tiny chip a fraction of an inch on a side that 20 years earlier would have been provided by a computer that filled a whole room and cost many millions of dollars.

5. Individual chips are mounted on carriers with several dozen connector leads emerging from them. These, in turn, are soldered together onto printed circuit boards that may contain many dozens of chips. In large computers the boards themselves are mounted into large racks and again connected together.

6. By the mid-1980s integrated circuits made with the most advanced technology could carry as many as a million individual transistors, each only a few microns on a side. (A micron is a thousandth of a millimeter, or 0.00004 inch.) Many electrical engineers and scientists believe that the ultimate limits of size in these circuits might soon be reached.

7. It was expected that the circuit elements would become too small and contain too few individual atoms to be manufactured reliably. To continue the reduction in size and cost of microcircuits, new principles of operation may be required, perhaps involving specially designed organic molecules.

II. Read the text and answer the questions.

1. What does the manufacture of integrated circuits consist of?

2. When did advancing technology reduce the size of individual circuit elements by a factor of two every two years?

3. What allowed the development of microprocessors?

4. What do microprocessors comprise?

5. What could integrated circuits carry by the mid-1980s?

6. What is necessary to continue the reduction in size and cost of microcircuits?

III. Give the main points of the text in 5-6 sentences.

UNIT 5

Part A

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