The Central processing Unit, Control Unit, Arithmetic-logical Unit, Memory or Main storage

[1] It is common practice in computer science for the words “computer” and “processor” to be used interchangeably. More precisely, “computer” refers to the central processing unit(CPU)together with an internal memory.The internal memory or main storage,control and processing components make up the heart of the computer system. Manufacturers design the CPU to control and carry out basic instructions for their particular computer.

[2] The CPU coordinates all the activities of the various components of the computer. It determines which operations should be carried out and in what order. The CPU can also retrieve information from memoryand can store the results of manipulations back into the memory unitfor later reference.

[3] In digital computers the CPU can be divided into two functional units called the control unit (CU)and the arithmetic-logical unit (ALU).These two units are made up of electronic circuits with millions of switches that can be in one of two states, either on or off.

[4] The function of the control unit within the central processor is to transmit coordinating control signals and commands. The control unit is that portion of the computer that directs the sequence or step-by-step operations of the system, selects instructions and data from memory, interprets the program instructions, and controls the flow between main storage and the arithmetic-logical unit.

[5] The arithmetic-logical unit, on the other hand, is that portion of the computer in which the actual arithmetic operations, namely, addition, subtraction, multiplication, division and exponentiation, called for in the instructions are performed. It also performs some kinds of logical operations such as comparing or selecting information. All the operations of the ALU are under the direction of the control unit.

[6] Programs and the data, on which the control unit and the ALU operate, must be in internal memory in order to be processed. Thus, if located on secondary memory devices such as disks or tapes, programs and data are first loaded into internal memory.

[7] Main storage and the CPU are connected to a console,where manual control operations can be performed by an operator.The console is an important, but special purpose, piece of equipment. It is used mainly when the computer is being started up, or during maintenance and repair. Many mini and micro systems do not have a console.

IX. Which statement best expresses the main idea of the text? Why do you think so?

1. Main storage is not a part of the processor.

2. The CPU is made up of the control unit, arithmetic-logical unit and internal memory.

3. The CPU is composed of the arithmetic-logical unit and con­trol unit only.

X. Say "True” or "False ". If “False", correct the sentence. Rely on the information from the text.

1. The central processing unit is made up of three components.

2. The CPU is responsible for all the activities taking place within a computer.

3. The processor itself has three components.

4. The control unit directs the flow of information within the processor.

5. The arithmetic-logical unit of the processor is responsible for the interpretation of program instructions.

6. The arithmetic-logical unit is also responsible for choosing and comparing the appropriate information within a pro­gram.

7. The processor cannot operate on any information if that in­formation is not main storage.

8. Secondary memory and internal memory are located in the same place in the computer system.

9. Only after the data has been processed by the CPU can re­sults be transmitted to an output device.

10. Computers can solve problems more quickly if they operate on new information.

XI. Use the texts you have studied so far to complete the following table.

System	Subsystem	Parts	Functions
Computer	Input devices
	Processor	Memory
			1.
			2.
			3.
			4.
		Arithmetic	1.
			2.
	Output
	devices

Unit 5 “Motherboard”

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

Personal, signal, voltage, technique, processor, infrastructure, function, component, personalize, enthusiast, microprocessor, specification, peripheral, architecture, cable, communicate.

II. Read the text and find English equivalents to the following word combinations:

Многослойная печатная схема; медные каналы схемы; методы послойного изготовления; короткое замыкание в цепи; синхронизирующий сигнал; посредством взаимосвязанных проводов; устройство, работающее от батарейки; исключает необходимость; данные, к которым недавно обращался центральный процессор; смонтированные на поверхности маленьких плат.

III. Phrases with prepositions for you to remember:

1. to be responsible for – отвечать (за), быть ответственным (за)

2. to allow for – предусматривать, учитывать, принимать во внимание

IV. Translate the following sentences into Russian paying attention to the Gerundial Construction:

1. I've heard of their experiment being successfully completed in the nearest future. 2. Mr. Brown’s taking part in the design of the new data processing system was of great help to us. 3. We were told about their having studied a number of problems connected with the development of computing machinery. 4. Mankind is interested in ato­mic energy being used only for peaceful purposes. 5. Benjamin Franklin's having invented the first lightning conductor is a well established fact. 6. We all know of their designing a new type of computer. 7. He men­tioned his having shown these slides at the conference. 8. Your having worked at the plant helped you to master technical subjects. 9. Kurchatov's having devoted all his life to nuclear physics is known to every­body. 10. I know of their being shown the new device. 11. We remembered having mentioned the works of this scientist. 12. We know of the Curies' having discovered some new radioactive elements. 13. We know of Rutherford's having investigated the nature of alpha-particles. 14. We insisted on the experiment being repeated. 15. There was no hope of their solving this complex engineering problem so soon.

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

adapter card – адаптерная плата

to allow for – предусматривать, принимать во внимание, учитывать

expansion bus slot – гнездо подключения к шине расширения

miscellaneous – разнообразный, смешанный

flash BIOS – система BIOS, записанная во флэш-памяти

compatibility - совместимость

configuration jumper – конфигурационная перемычка (для выбора конфигурации устройства)

printed circuit – печатная схема

copper - медный

trace - трассировка

to resemble –напоминать, быть похожим

ground - заземление

insulated – изолированный, обособленный

to plug into – подключать(ся)

form factor – коэффициент формы, форм-фактор

to channel - направлять

to retrieve – извлекать, отыскивать

hardwired – подключенный с помощью провода

to erase - стирать

power connector – разъем питания

light-emitting diode - светодиод

timing - синхронизация

to etch - вытравливать

SCSI (small computer system interface) – «СКАЗИ», интерфейс малых компьютерных систем для подключения периферийных устройств, других компьютеров

shot-circuit – короткое замыкание, цепь короткого замыкания

intersection – пересечение, линия пересечения

to swap – менять, обменивать; swap out – разгрузка, откачка

cache – КЭШ (быстродействующая буферная память большой емкости)

to reside – находиться

volatile – непостоянный, энергозависимый

VI. Read and translate the text.

Motherboard

A motherboard(also called mainboard)has been an integral part of most personal computers for more than 20 years. It is a multi-layered printed circuit board. Copper circuit paths called tracesthat resemble a complicated roadmap carry signals and voltages across the motherboard. Layered fabrication techniques are used so that some layers of a board can carry data for the input/output, processor and memory buses while other layers can carry voltage and ground returns without circuit paths short-circuiting at intersections. The insulated layers are manufactured into one complete, complex "sandwich." The motherboard is the data and power infrastructure for the entire computer. Various circuit cards performing various functions all plug into many similar sockets on a common circuit board. Each circuit card performs a unique function in the computer and gets its power from the socket as well.

Different motherboards of different vintages typically have different form factors.Form factor essentially means the size and shape of the actual motherboard. There are more than a half-dozen form factors for motherboards, with the most recent ones having the designation of NLX.Right now, the designation ATXis the most prevalent. By buying a computer with a true ATX motherboard, you are assured that you will have the ability to upgrade by being able to re-use the personal computer case with a more recent replacement ATX board design. Motherboards have helped to keep the "personal" in personal computing since pluggable components allow the user to personalize the system depending on their applications and needs. For example: prolific collectors of digital camera images or video will want to add a SCSI hard disk drive to an open bay and use an empty socket on the motherboard for the SCSI controller card; serious game enthusiasts will want the fastest video card possible with as much memory on the card as possible.

Common Motherboard Items

CPU (central processing unit) or microprocessor is the brain of the computer.It reads and interprets software instructions and coordinates the processing activities that must take place. All computer components channel data and instructions to and from the CPU.

RAM (random-access memory) is slots or sockets and integrated circuits or chips surface-mounted on small circuit boards. The more RAM you can install in a computer (up to the maximum supported by the system), the better. RAM enables a computer to store actively running applications and their data without swapping out to the hard disk drive. It’s a volatile type of memory.

Cache socket. This socket is reserved for a Level 2 cache (L2, cache memory that can be accessed more quickly than the primary cache) or secondary cache memory module. L2 cache consists of fast memory called SRAM (static RAM). Computers with L2 cache perform better than those that lack L2 cache. This cache stores operations or data recently accessed by the CPU, allowing the processor to retrieve this information much more quickly than if the data resided in conventional RAM.

System chipset isalso called the "support chipset." This collection of logic circuits is responsible for transferring information to and from all other motherboard circuits, adapter card connectors, and disk drives. Chipset specifications allow for compatibility with PCI (Peripheral Component Interconnect) and ISA (Industry Standard Architecture) buses and the IDE (Integrated Drive Electronics) disk storage interface.

Expansion bus slots typically include PCI, ISA, and AGP (Accelerated Graphics Port) connectors for adapter cards designed to handle audio, video, and other subsystems. Once added, adapter cards fasten to the back of the case with a screw. Without slots, a computer would be limited to the circuitry permanently wired to the motherboard.

Disk interface presents connectors for floppy diskette and IDE hard disk drives. You attach a ribbon cable from a disk interface connector on the motherboard to the hard drive or floppy drive.

Miscellaneous I/O (input/output) ports and connectors. These devices get their name because information is sent in and out of them. Previously there were a lot of different cables to be connected to the board. Newer computers eliminate the need for cables because the connectors are integrated on the board. Modern motherboards also have hardwired USB (Universal Serial Bus) connectors letting you attach USB devices to the computer's back panel. A mouse connector on the motherboard cables to a PS/2-style port at the back of the computer for input devices such as a mouse or trackball. A keyboard connector (typically hardwired to the motherboard) cables to a keyboard port at the panel at the back of the computer so you can attach a keyboard.

The BIOS (Basic Input/Output System) chip holds the code that starts up your computer. Newer systems have a flash BIOS, storing the code on EPROM (erasable programmable read-only memory; memory that can be erased when exposed to ultraviolet light), so users can update a system's existing BIOS with new code.

Miscellaneous parts. This category includes the CMOS (complementary metal-oxide semiconductor, an electronic component used for RAM and fast data switching), real-time clock (the battery-powered device that keeps track of system time and date), plus several configuration jumpers and switches, power connectors, light-emitting diodes, and front-panel electrical connectors.

As the motherboard works, data and timing signals transfer from one connected component to the other by way of interconnected leads etched into the board. These leads are known as the system bus. The power supply, which also connects to the motherboard, distributes power to all system components via the bus. The processor also communicates with motherboard components by sending and receiving instructions and data over the bus.

VII. Answer and discuss the following questions:

1. What is motherboard?

2. How do you understand “layered fabrication techniques” of motherboard?

3. What does form factor influence?

4. What are the main parts of motherboard?

5. With what part the principle “The more, the better” is true and why?

6. What new developments in motherboard fabrication do you know?

VIII. Match the words with their definitions:

1. motherboard 2. traces 3. layered fabrication technique 4. form factor 5. CPU 6. RAM 7. cache 8. system chipset 9. BIOS

a. computer’s central processing and control circuitry b. system for starting up of the computer c. multilayered printed circuit board d. transfers information to and from other circuits and disc drive e. complex “sandwich” fabrication f. copper circuit paths g. size and shape of motherboard h. very fast memory of great capacity i. volatile memory for temporary storage

UNIT 6 “Removable storage”

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

Magnetic, audio, cassette, commercial, option, optical, mechanical, oxide, concentric, mechanism, diameter, controller, digital, design, microscopic, temperature, crystallize, industry, electron, industrial.

II. Translate the following word combinations:

Removable storage, paper punch cards, commercial software, back-up copy, storage capacity, iron oxide, direct-access storage, magnetic medium, flexible plastic film, software application, sealed aluminum box, controller electronics, magnetic domains, highly-filtered vent hole, extremely simple, pie-shaped wedges, magnetic flux patterns.

III. Phrases with prepositions for you to remember:

1. to be coated with – быть покрытым

2. to distinguish from – отличать, различать

3. to turn into – превращать(ся)

4. to detach from – отделять, отсоединять, разъединять

IV. Memorize the following “false friends”:

1. extremely – чрезвычайно, в высшей степени, очень

2. originally – первоначально, изначально, поначалу

V. Translate the following sentences into Russian paying attention to the Absolute Participial Construction:

1. The experiments being demonstrated, all the students watched them with great attention. 2. There are two diagrams in this figure, one of them showing the relation between volume and temperature. 3. A new radio set having been shown to them, they began to examine its details. 4. Electrons leaving the surface, the metal becomes posi­tively charged. 5. We defined the volume, all the measurements having been done with respect to the instruction. 6. The computer performing addition, two numbers to be added come from the memory. 7. Atoms consist of three kinds of particles — electrons, protons and neutrons, the number of particles determining the kind of element. 8. The workers increased the output of measuring instruments, new devices having been applied in all the shops of the plant. 9. The experiment having been carried out, the students left the lab. 10. I was writing the translation, my friend helping me. 11. Part of the energy being changed into heat, not all the chemical energy of the battery is transformed into electric energy.

VI. Choose the sentences with the Absolute Participial Construc­tion from the ones given below. Translate them into Russian:

1. Speaking about the new method of work the engineer told us many interesting details. 2. The temperature of a conductor being raised, the motion of the electrons in the conductor increases. 3. Special instruments measuring cosmic radio signals are being installed in the observatory. 4. Transistors are very sensitive to light, some of them reacting even to star-light. 5. The first man-made satellite having been sent up, it became possible to investigate various types of radiation. 6. Obtaining new data engineers can improve their knowledge. 7. The re­sistance being very large, the current in the circuit was small. 8. When improving the design the constructor made many calculations. 9. A great variety of substances are semi-conductors, germanium and silicon being the most important of them. 10. A series of attempts having been made, Lodygin came to a successful solution of the problem.

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

back-up copy – запасная (резервная) копия

to secure – защищать, обеспечивать безопасность

incredible – невероятный, удивительный

enduring – выдержавший испытание временем

drive – привод, дисковод

direct-access storage – ЗУ с прямым доступом

platter – большой диск

GIF (Graphic Interchange Format) – формат графического обмена

sealed – герметичный, запечатанный

controller electronics – электронное управление

to spin – вращать

to assemble – компоновать, собирать, монтировать

underneath – внизу, ниже (относительно какого-либо объекта)

vent – воздушный клапан

to equalize – уравновешивать, выравнивать

precise – точный, точно установленный

tolerance – устойчивость

hub – центр

edge – край

wedge – что-либо, имеющее форму клина

cluster – кластер, группа, блок

instantly – мгновенно, сразу же

flux - поток

VIII. Read and translate the text:

Removable Storage

Removable storage has been around almost as long as the computer itself. Early removable storage was based on magnetic tape like that used by an audio cassette. Before that, some computers even used paper punch cardsto store information.

We've come a long way since the days of punch cards. New removable storage devices can store hundreds of megabytes (and even gigabytes) of data on a single disk, cassette, card or cartridge. There are several reasons why removable storage is useful: it’s commercial software, you can make back-up copies for storing software and information that you don't need to access constantly, it’s possible to transport data between two computers (e.g. copying information to give to someone else), you can secure information that you don't want anyone else to access.

Modern removable storage devices offer an incredible number of options, with storage capacities ranging from the 1.44 megabytes (MB) of a standard floppy to the upward of 700 gigabyte (GB) capacity of some portable drives. All of these devices fall into one of three categories: magnetic storage, optical storage, solid-state storage.

MAGNETIC

Floppy disc

The most common and enduring form of removable-storage technology is magneticstorage. For example, 1.44-MB floppy-disk drives using 3.5-inch diskettes have been around for about 15 years, and they are still found on many computers sold today. In most cases, removable magnetic storage uses a drive,which is a mechanical device that connects to the computer. You insert the media,which is the part that actually stores the information, into the drive.

Just like a hard drive, the media used in removable magnetic-storage devices is coated with iron oxide.A disk is made from a thin piece of plastic coated with magnetic material on both sides. On the disk there are tracks. The tracks are arranged in concentric ringsso the software can jump from "file 1" to "file 19" without having to fast forward through files 2 through 18. The disk spins like a record and the heads move to the correct track, providing what is known as direct-access storage.

The read/write heads ("writing" is saving new information to the storage media) do not touch the media when the heads are traveling between tracks. There is normally some type of mechanism that you can set to protect a disk from being written to.

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

OPTICAL

CD

The optical storage device that most of us are familiar with is the compact disc (CD). A CD can store huge amounts of digital information (783 MB) on a very small surface. The design that makes this possible is a simple one. The CD surface is a mirror covered with billions of tiny bumps that are arranged in a long, tightly wound spiral. The CD player reads the bumps with a precise laser and interprets the information as bits of data.

The spiral of bumps on a CD starts in the center. CD tracks are so small that they have to be measured in microns(millionths of a meter). Most of the mass of a CD is an injection-molded piece of clear polycarbonate plastic that is about 1.2 millimeters thick. During manufacturing, this plastic is impressed with the microscopic bumps that make up the long, spiral track. A thin, reflective aluminum layer is then coated on the top of the disc, covering the bumps. The tricky part of CD technology is reading all the tiny bumps correctly, in the right order and at the right speed. To do all of this, the CD player has to be exceptionally precise when it focuses the laser on the track of bumps.

When you play a CD, the laser beam passes through the CD's polycarbonate layer, reflects off the aluminum layer and hits an optoelectronic device that detects changes in light. The bumps reflect light differently than the flat parts of the aluminum layer, which are called lands.The optoelectronic sensor detects these changes in reflectivity, and the electronics in the CD-player drive interpret the changes as data bits.

CD-R works by replacing the aluminum layer in a normal CD with an organic dye compound. This compound is normally reflective, but when the laser focuses on a spot and heats it to a certain temperature, it "burns" the dye, causing it to darken. When you want to retrieve the data you wrote to the CD-R, the laser moves back over the disc and thinks that each burnt spot is a bump. The problem with this approach is that you can only write data to a CD-R once. After the dye has been burned in a spot, it cannot be changed back.

CD-RW fixes this problem by using phase change,which relies on a very special mixture of antimony, indium, silver and tellurium. This particular compound has an amazing property. When heated to one temperature, it crystallizes as it cools and becomes very reflective; when heated to another, higher temperature, the compound does not crystallize when it cools and so becomes dull in appearance.

CD-RW drives have three laser settings to make use of this property:

• Read- The normal setting that reflects light to the optoelectronic sensor

• Erase- The laser set to the temperature needed to crystallize the compound

• Write- The laser set to the temperature needed to de-crystallize the compound

Other optical devices that deviate from the CD standard, such as DVD, employ approaches comparable to CD-R and CD-RW.

DVD

DVD,the Digital Versatile Disc, is a high capacity CD-size disc for video, multimedia, games and audio applications. DVD started in 1994 as two competing formats, Super Disc (SD) and Multimedia CD (MMCD). Capacities for the read-only disc range from 4.7GB to 17.1GB. The high quality of video and audio has helped DVD-Video to compete very effectively with VHS.

DVD-Video,which was launched in 1997 in the USA, has become the most successful of all the DVD formats, as it has proved to be an ideal vehicle for distributing video content from the movie industry. It can store a full-length movie in high quality video with surround sound audio on a disc the same size as a CD.

DVD-ROMis beginning to replace the CD-ROM and provide a new high capacity disc format for the computer industry. New PCs are now provided with DVD drives instead of CD drives. The entertainment industry has developed new games consoles (e.g. Sony's PS2 and Microsoft's X-Box) which incorporate DVD-ROM drives for more sophisticated and realistic games applications.

DVD-Audio,which was launched in 2000, is slowly gathering momentum to become the format for very high quality, surround sound music, offering the music industry new revenue opportunities.

Recordable formats such as DVD-RAM,DVD-RWand DVD-Rare now being extensively used in PCs for computer backup and short runs of DVDs and in standalone products such as video recorders and camcorders.The main features of the DVD formats are:

• Backwards compatibility with current CD media. All DVD hardware will play audio CDs and CD-ROMs and most will play CD-Rs and CD-RWs.

• Physical dimensions are identical to the compact disc but each disc comprises two 0.6 mm thick substrates, bonded together.

• Single-layer/dual-layer and single/double sided options are available.

• Up to 4.7 GB read-only capacity per layer, 8.5 GB per side maximum.

• Designed from the outset for video, audio and multimedia, not just audio.

• All formats use a common file system (UDF).

• Digital and analogue copy protection for DVD-Video and DVD-Audio built into the standard.

• Recordable and re-writable versions are part of the family.

Although identical in appearance, DVDs and CDs differ in a number of key physical parameters. To meet the requirements for 133 minutes of high quality video on one side of a single disc requires the use of a thinner (0.6 mm) substrate, two of which are bonded together to form a disc that is thick enough for general use. The use of a sandwich of two substrates allows a range of formats from one layer to four and one or two sides, giving capacities from 4.7 GB to as much as 17.1 GB.

All types of DVD discs (DVD-Video, DVD-ROM and DVD-Audio) contain data in files. These files are accessed using a file system common to all DVD discs. For compatibility with recordable and re-writable versions and with existing operating systems, including Windows9x and later the UDF Bridge Format was chosen.

DVD-ROM is essentially the pre-recorded DVD physical and logical format used for DVD-Video, DVD-Audio and a range of other applications, particularly general computer and multimedia applications, for which it can provide at least 7 times the capacity of a CD-ROM. Applications can include MPEG-2 video, as used on DVD-Video discs, to give added realism to games and richer content for multimedia applications. DVD-ROM drives will also play CD-ROM and CD audio discs and are forecast to replace CD-ROM drives within the next few years. They are already available as add-on drives and built into new PCs.

Copy protection for DVD is only for video and audio content and comprises both digital and analogue methods for preventing users from making perfect copies of the source material.

UNIT 8 “Modems”

1. Read and translate the following international words:

To communicate; to concentrate; to electrify; standard; technique; to manipulate; diagram.

II. Read the text and find English equivalents for the following Russian words and word combinations:

Обрабатывать информацию; двойной язык; связка единиц и нулей; более общий термин; произвольно; в обратном направлении; единственный недостаток.