Computers today: Учебно-методическое пособие для вузов

ФЕДЕРАЛЬНОЕ АГЕНТСТВО ПО ОБРАЗОВАНИЮ ГОСУДАРСТВЕННОЕ ОБРАЗОВАТЕЛЬНОЕ УЧРЕЖДЕНИЕ ВЫСШЕГО ПРОФЕССИОНАЛЬНОГО ОБРАЗОВАНИЯ «ВОРОНЕЖСКИЙ ГОСУДАРСТВЕННЫЙ УНИВЕРСИТЕТ»

COMPUTERS TODAY Учебно-методическое пособие для вузов

Составитель: В.И. Гурьянова

Издательско-полиграфический центр Воронежского государственного университета 2009

Утверждено научно-методическим советом факультета РГФ 9 декабря 2008 г., протокол № 4

Рецензент: кандидат филологических наук, доцент кафедры английской филологии факультета РГФ Н.В. Костенко

Учебное пособие подготовлено на кафедре английского языка факультета романо-германской филологии Воронежского государственного университета.

Предназначено для студентов 1 курса дневного отделения факультета прикладной математики, информатики и механики.

Для специальностей: 010501 – Прикладная математика и информатика, 010901 – Механика.

Введение Предлагаемое учебное пособие предназначено для самостоятельной работы студентов 1 курса факультета прикладной математики, информатики и механики над литературой по специальности на английском языке. В пособие включена подборка оригинальных текстов по профилю будущей специальности, часть которой подвергнута незначительной обработке по соображениям методического характера. Тексты снабжены заданиями, направленными на формирование навыков как быстрого информативного, так и изучающего чтения литературы по специальности и умений аннотирования и реферирования. В пособие включен список фраз-клише для составления аннотаций к текстам. Части пособия «Before you read» и «After you read» ставят целью предварить и, соответственно, подытожить работу с текстами и обеспечивают развитие навыков ведения беседы на профессиональные темы. Пособие может быть использовано для работы в аудитории.

Part I. Before you read 1. Do you use computers? Why do you use them? What do you like about them and what do you not like? Do you think you are a computerliterate person? 2. Here is Bill Gates’ opinion about computers. To what extent do you agree with it? Is this true now? How can computers become even more useful in future? “Our computers will be our telephones, our post-office, our library and our books”. 3. Why do you think so many men are keen on computers? Write a few sentences about it. 3

Part II. Practise reading the texts. Follow the instructions 1. Look at the headings of all the texts below and decide whether all of them cover the same topic. According to the headings, is it possible to classify the texts into some basic subtopics? Comment on the point. 2. Judging by the headings, can you work out roughly what each text may be about?

Text 1 1. Read the text below carefully. Is there anything in the text that you find particularly interesting or new? Tell the rest of the class about it. 2. These expressions appear in the text. What ideas do you think the author puts across through them?  Opened up a new era  These human computers  The decisive step to a full-blown computing machine  The so called Church-Turing thesis  It comes from the Latin version 3. Note down all the words and expressions in the text which have a specific technical or scientific meaning connected with computers and computations. 4. Which paragraphs of the text can the words below be included into? Using them, write 2-3 sentences to expand the main topics of those paragraphs: abacus, sliding rule, the greatest common divisor, two numbers, Euclid’s algorithm. 4

Computers Computer is an electronic device that can receive a program and then carry out this program by calculating numerical information. The modern world of high technology is possible mainly due to the development of the computer. Computers have opened up a new era in manufacturing by means of automation, and they have enhanced modern communication systems. Electronic computers have been around since the end of World War II. Before that time, computers were people working in big insurance companies or ballistic research laboratories performing long and tedious calculations. These human computers used desk calculators to perform simple subtasks of addition and multiplication, combining these subtasks into the computation of more complex functions. During the war, new artillery weapons were developed at such a pace that the human computers were falling far behind in computing the necessary firing tables. As a result, the U.S. government was interested in supporting attempts to construct “an automatic calculator”. Early machines such as Aiken’s Mark 1 used electromagnetic relay technology. The decisive step to a full-blown computing machine was taken when the machines were made electronic, and with the capability of storing programs in their memories. The electronic representation of data made it possible to change the contents of registers much faster than in the mechanical machines. The idea of looking at computational procedures as data and of storing programs in memory made it possible and easy to change the function to be computed. Electronic computers were built to replace human computers. They were designed as technical devices to be fed with numbers and computational procedures. They could compute according to prescribed procedures and deliver the computed results as output. 5

Classical computer science has linked human computing and machine computing in the so-called Church-Turing thesis: Everything that a human being can compute can be computed by a machine. According to this thesis, our intuitive understanding of computation refers to the set of computations that can be formally prescribed. Closely related to this idea is the concept of an algorithm. An algorithm is a set of rules or instructions for getting a desired output from a given input. The word “algorithm” originated in the Middle East. Curiously enough it comes from the Latin version of the last name of the Persian scholar Abu Jafar Mohammed ibn Musa al-Khowaresmi (Algorithmi) whose textbook on arithmetic (825 A.D.) employed for the first time Hindu positional decimal notation and gave birth to algebra as an independent branch of mathematics. It was translated into Latin in the 12th century and had a great influence for many centuries on the development of computing procedures. The name of the textbook’s author became associated with computations in general and used as a term “algorithm”. Personal computing is a partnership between the person and the computer. Believe it or not, a personal computer is easier to operate than a car. It’s even easier to operate than a telephone, which comes with no instructions at all. Suddenly, personal computers invaded our world. It’s not surprising that it takes most of us a while to get comfortable with a comparatively new technology that so quickly arrived on the scene.

Text 2 1. Read the text “Using computers”. Do you think the style of the text is:  Serious and analytical?  Enthusiastic and persuasive?  Ironical and amusing?  Positive and optimistic?  Negative and critical?

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2. Here are some ideas in note form. Using information from the text below expand them into a short paragraph. Begin with the sentence given: There are various things that you can do using your computer

work with texts

effective tools

study things

children

modify

pilots

combine

money

help and liberate

construction design

to be trained

boring tasks

3. Some parts of the text are about problems computers cause. Find these parts and translate them into Russian (in writing).

Using computers Think of the first time you succeeded in making a computer do what you intended it to do. Think of the feeling it gave you to be in control of a powerful machine. Before getting too excited, don’t forget the times you had to struggle to make the computer do what you wanted. You could not get the right result, or, worse, there was no reaction at all. Remember the direct way in which mistakes 7

or inconsistencies in your first programs were revealed and the difficulties you sometimes had when you were trying to correct the programs? You knew that something was wrong, but you had no idea what it was. Computers are fascinating because they are fast, powerful, and extremely versatile machines, and because they are programmable. They will obey our most whimsical commands, provided they can interpret them. It is really magic: They do exactly what we tell them to do. But, of course, we have to think and express ourselves clearly; we have to be careful with our words. We can use computers to play with texts and immediately see the consequences. It is easy to reuse text and to experiment with different formulations and the sequence in which we present our argument. There is no guarantee, of course, that texts produced on computers are better in quality, or clearer and richer. Nevertheless, computers are extremely effective tools for producing, modifying, and combining texts, and they offer us fascinating opportunities to play and to experiment, while we try to be convincing, clear or even poetic. We can also use computers to explore the world without having to suffer real-world consequences. Kids fight monsters without ever getting hurt. Pilots are trained in flight simulators without the hazards and high costs. Investments are evaluated without running the risk of losing fortunes. And bridges and highways are designed and tested without the risk of collapses or the inconvenience of traffic jams. In general, we use computers to process, communicate, store, and keep track of information. Computers also provide us with new and useful opportunities, and they liberate us from many laborious and boring tasks. It is not surprising that the development of computer systems raises difficult questions. We use computers to automate administrative tasks and to mechanize and automate production processes. But how can we make sure that the good qualities of the traditional manual way of doing things are not lost? And what about the people who lose their jobs because of the computer? 8

Computers provide us with data that give us a basis for decision making – but to what extent can we rely on those data? Are the data up-to-date and correct? What kinds of interpretations were made when the data were originally registered? What about the uncertainties introduced by our own interpretations? Computers are used to monitor and control complex technical systems to minimize errors and avoid breakdowns and catastrophes. But computer systems are themselves complex artifacts that introduce new source of error and uncertainty. And what about political issues? Do we want to use computers to keep track of people’s every move and opinion? Do we want to use them to develop advanced military systems in outer space? All these questions concern quality. People are concerned with the quality of work as computers replace old work habits and introduce new ones. We have to worry about the quality of data and information when computers are used, as they so often are, to provide decision support.

Text 3 1. Before you read the text below, check that you understand the following words and phrases: in order to do smth, to solve problems, to devise, to imply, a useful whole, to recognize, the processing of data, to direct, to join together, either … or, to refer, the actual execution of programs, to attach to the CPU, system software, applications software, the former, the latter, along with, monstrosity, incapable, to acquire. 2. Read the text, then answer the questions:  What is a computer system?  What are the 2 main parts of a computer system?  What components of computer hardware are mentioned in the text?  What is software? 9

 What are the 2 main types of software?  What’s the difference between system software and applications software?  What does the successful work of a computer depend on? 3. State the most important ideas in each paragraph. Identify the relationships between these ideas and make up the plan of the text. 4. Summarize the text using your plan.

Hardware and software In order to use computers effectively to solve problems in our environment, computer systems are devised. A “system” implies a good mixture of integrated parts working together to form a useful whole. Computer systems may be discussed in two parts. The first part is hardware: the physical, electronic, and electromechanical devices that are thought of and recognized as ‘computers’. The second part is software – the programs that control and coordinate the activities of the computer hardware and direct the processing of data. The basic components of computer hardware are joined together in a computer system. The central part is called either the computer, the processor, or usually the central processing unit (CPU). The term “computer” usually refers to those parts of the hardware in which calculations and other data manipulations are performed, and to the internal memory in which data and instructions are stored during the actual execution of programs. Various peripherals, which include input and/or output devices, various secondary memory devices, and so on, are attached to the CPU. Computer software can be divided into two very broad categories – system software and applications software. The former is often simply referred to as ‘systems’. These, when brought into internal memory, direct the computer to perform tasks. The latter may be provided along with the hardware by a systems supplier as part of a computer product designed to meet specific needs in certain areas. 10

The success or failure of any computer system depends on how skillfully and cleverly the hardware and software components are selected and combined. A poorly chosen system can be a monstrosity incapable of performing the tasks for which it was originally acquired.

Text 4 1. Read the text below quickly and make up its plan on the basis of its heading and subheadings. Put the plan down into your copy-book. 2. Read the text more carefully and prepare a short talk using the items of your plan as starting points. 3. Look through the text again and find the paragraph: 1) that compares computers, 2) that describes 2 main types of memory. Do the written translation of these parts of the texts.

Computer and its components When you mention the word “technology”, most people think about computers. Computers take numerous physical forms. Early electronic computers were the size of a large room, consuming as much power as several hundred modern personal computers. Today, computers can be made small enough to fit into a wrist watch and be powered from a watch battery. Society has come to recognize personal computers and their portable equivalent, the laptop computer, as icons of the information age; they are what most people think of as “a computer”. However, the most common form of computer in use today is by far the embedded computer. Embedded computers are small, simple devices that are often used to control other devices-for example, they may be found in machines ranging from fighter aircraft to industrial robots, digital cameras, and even children’s toys. The ability to store and execute programs makes computers extremely versatile and distinguishes them from calculators. The Church-Turing thesis is a 11

mathematical statement of this versatility: Any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore, computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks as long as time and storage capacity are not considerations. A general purpose computer has four main sections: the arithmetic and logic unit (ALU), the control unit, the memory, and the input and output devices (collectively termed I/O). These parts are interconnected by buses, often made of groups of wires. The control unit, ALU, registers, and basic I/O (and often other hardware closely linked with these) are collectively known as a central processing unit (CPU). Early CPUs were comprised of many separate components but since the mid-1970s CPUs have typically been constructed on a single integrated circuit called a microprocessor. Control unit The control unit (often called a control system or central controller) directs the various components of a computer. It reads and interprets (decodes) instructions in the program one by one. The control system decodes each instruction and turns it into a series of control signals that operate the other parts of the computer. Control systems in advanced computers may change the order of some instructions so as to improve performance. A key component common to all CPUs is the program counter, a special memory cell (a register) that keeps track of which location in memory the next instruction is to be read from. Since the program counter is conceptually just another set of memory cells, it can be changed by calculations done in the ALU. Adding 100 to the program counter would cause the next instruction to be read from a place 100 locations further down the program. Instructions that modify the program

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counter are often known as “jumps” and allow for loops (instructions that are repeated by the computer) and often conditional instruction execution. It is noticeable that the sequence of operations that the control unit goes through to process an instruction is in itself like a short computer program – and indeed, in some more complex CPU designs, there is another yet smaller computer called a micro sequencer that runs a microcode program that causes all of these events to happen. Arithmetic/logic unit (ALU) The ALU is capable of performing two classes of operations: arithmetic and logic. The set of arithmetic operations that a particular ALU supports may be limited to adding and subtracting or might include multiplying or dividing, trigonometry functions (sine, cosine, etc) and square roots. Some can only operate on whole numbers (integers) whilst others use floating point to represent real numbers-albeit with limited precision. However, any computer that is capable of performing just the simplest operations can be programmed to break down the more complex operations into simple steps that it can perform. Therefore, any computer can be programmed to perform any arithmetic operation-although it will take more time to do so if its ALU does not directly support the operation. An ALU may also compare numbers and return Boolean truth values (true or false) depending on whether one is equal to, greater than or less than the other (“is 64 greater than 65?”). Memory A computer’s memory may be viewed as a list of cells into which numbers may be placed or read. Each cell has a numbered “address” and can store a single number. The computer may be instructed to “put the number 123 into the cell numbered 1357” or to “add the number that is in cell 1357 to the number that is in cell 2468 and put the answer into cell 1595”. The information stored in memory may represent practically anything. Letters, numbers, even computer instructions may be placed into memory with equal ease. Since the CPU does 13

not differentiate between different types of information, it is up to the software to give significance to what the memory sees as nothing but a series of numbers. In almost all modern computers, each memory cell is set up to store binary numbers in groups of eight bits (called a byte). Each byte is able to represent 256 different numbers; either from 0 to 255 or –128 to +128. To store larger numbers, several consecutive bytes may be used (typically, two, four or eight). When negative numbers are required, they are usually stored in two’s complement notation. Other arrangements are possible, but are usually not seen outside of specialized applications or historical contexts. A computer may store any kind of information in memory as long as it can be somehow represented in numerical form. Modern computers have billions or even trillions of bytes of memory. The CPU contains a special set of memory cells called registers that can be read and written too much more rapidly than the main memory area. There are typically between two and one hundred registers depending on the type of CPU. Registers are used for the most frequently needed data items to avoid having to access main memory every time data is needed. Since data is constantly being worked on, reducing the need to access main memory (which is often slow compared to the ALU and control units) greatly increases the computer’s speed. Computer main memory comes in two principal varieties: random access memory or RAM and read-only memory or ROM. RAM can be read and written to anytime the CPU commands it, but ROM is pre-loaded with data and software that never changes, so the CPU can only read from it. ROM is typically used to store the computer’s initial start-up instructions. In general, the content of RAM is erased when the power to the computer is turned off while ROM retains its data indefinitely. In a PC, the ROM contains a specialized program called the BIOS that orchestrates loading the computer’s operating system from the hard disk drive into RAM whenever the computer is turned on or reset. In embedded computers, which frequently do not have disk drives, all of the software required to perform the task may be stored in ROM. Software that is stored in ROM is often called firmware because it is notion14

ally more like hardware than software. Flash memory blurs the distinction between ROM and RAM by retaining data when turned off but being rewritable like RAM. However, flash memory is typically much slower than conventional ROM and RAM so its use is restricted to applications where high speeds are not required. In more sophisticated computers there may be one or more RAM cache memories which are slower than registers but faster than main memory. Generally computers with this sort of cache are designed to move frequently needed data into the cache automatically, often without the need for any intervention on the programmer’s part. Input/output (I/O) I/O is the means by which a computer receives information from the outside world and sends results back. Devices that provide input or output to the computer are called peripherals. On a typical personal computer, peripherals include inputs like the keyboard and mouse, and outputs such as the display and printer. Hard disks, floppy disks and optical disks serve as both inputs and outputs. Computer networking is another form of I/O. Practically any device that can be made to interface digitally may be used as I/O.

Text 5 1. Read the text below and say what characteristics are implied by its heading? Prove it using information from the text. 2. Now read the text more carefully and incorporate the extra information into the text. Where do you think should it go? 1. So programs and data, which pass through the CPU, must be loaded into the main (internal) memory in order to be processed. 2. When the user runs an application, the microprocessor looks for it on secondary storage devices (disks) and transfers a copy of the application into the RAM area. 3. By freeing people from routine work, computers greatly change the content of labour. Computer modelling eliminates the need of man’s presence 15

in harmful and dangerous conditions. Computer-aided design (CAD) is used in industry as part of the process of planning how to make such things as cars, aircraft, buildings, etc. 3. These sentences are wrong. Make any necessary corrections to them. 1. Man created the machine to fulfil his own requirements and it can think both logically and figuratively. 2. Moreover, it can have feelings, desires and emotions. 3. The mechanical and electronic components of a computer are known as software. 4. The internal operations are performed outside the computer. 5. When programs need to be stored temporarily, they are loaded onto secondary storage devices. 6. A computer is a machine used for a limited number of purposes. 7. It has always been cheap to have a computer. 8. Computers can hardly replace man in performing boring tasks and functions. 4. Translate into Russian the paragraph describing the three main stages in computer operation.

The computer characteristics Computers are electronic machines that process information. They are capable of communicating with the user, of performing arithmetic operations, and of making decisions. However, they are incapable of thinking. They accept data and instructions as input, and after processing the information, they output the results. When talking about computers, both hardware and software need to be considered. The former refers to the actual machinery, whereas the latter refers to the programs that control and coordinate the activities of the hardware. Computers are machines designed to process specially prepared pieces of information, which are termed data. Handling or manipulating the information 16

that has been given to the computer, in such ways as performing calculations, adding information or making comparisons is called processing. Computers are made up of millions of electronic devices capable of storing data or moving them at enormous speed, through complex circuits with different functions. All computers have several characteristics in common, regardless of their design. Information, in the form of instructions and data, is given to the machine after which the machine acts on it, and the result is then returned. The information presented to the machine is the input; the internal operations – the processing; and the result is the output. These three basic concepts of input, processing and output occur in almost every aspect of human life whether at work or at play. The term “computer” includes those parts of hardware in which calculations and other data manipulations are performed and the high-speed internal memory in which data and calculations are stored during actual execution of programs. When data or programs need to be saved for long periods of time they are stored in various secondary memory devices or storage devices. Computers have long been thought of as extremely large adding machines, but this is not true. Although a computer can only respond to a certain number of instructions it is not a single-purpose machine since these instructions can be combined in an infinite number of sequences. Therefore, a computer can do an unlimited number of things; its versatility is limited only by the imagination of those using it. In the late 1950s and early 1960s computers were very expensive to own and run. Moreover, their size and reliability were such that a large number of support personnel were needed to keep the equipment operating. This has all changed now. Computing power has become portable, more compact, and cheaper. In a very short period of time computers have greatly changed the way of doing everything. Computers can remove many of the routine and boring tasks from our lives. It goes without saying that computers have created a lot of new areas of work that did not exist before their development.

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Text 6 1. Read through the text below quickly and decide which are computer capabilities and which are limitations. 2. Where would you divide the text into paragraphs? Why? 3. How could you fit the following sentences into the text? How do you think they can improve it? 1. Actually all operations can be handled at any speed, it depends on the capability and sometimes the number of processors involved. 2. Such computer failures can be caused by different things, including program errors, that is why compiling a program requires great attention of a programmer. 3. Any computer operates exactly according to the program, so programmability is the fundamental trait of a digital computer found in machines of any era.

Computer capabilities and limitations As we know, computers have memories and can solve problems, but they can’t really think. That is, no machine has the capacity to reason and learn as we humans do. They can’t learn to recognize a particular person, for example, from an angle they’ve never seen before, the way even a baby can. They cannot make anything but yes-no decisions and they certainly can’t independently figure out how to solve problems without specific instructions from human programmers. Like all machines, a computer needs to be directed and controlled in order to perform a task successfully. Until a program is prepared and stored in the computer’s memory, the computer knows absolutely nothing, not even how to accept or reject data. Even the most sophisticated computer, no matter how capable it is, must be told what to do. Until the capabilities and the limitations of a computer are not recognized, its usefulness cannot be understood. In the first place, 18

it should be recognized that computers are capable of doing repetitive operations. A computer can perform similar operations thousands of times, without becoming bored, tired, or even careless. Secondly, computers can process information at extremely rapid rates. Thirdly, computers may be programmed to any level of accuracy specified by the programmer. These machines are very accurate and reliable, especially when the number of operations they can perform every second is considered. Because they are man-made machines, they sometimes malfunction or break down and have to be repaired. However, in most instances when the computer fails, it is due to human error and is not the fault of the computer at all. In the fourth place, general-purpose computers can be programmed to solve various types of problems due to their flexibility. One of the most important reasons why computers are so widely used today is that almost every big problem can be solved by solving a number of little problems – one after another. Finally, a computer, unlike a human being, has no intuition. A person may suddenly find the answer to a problem without working out too many of the details, but a computer can only proceed as it has been programmed to.

Text 7 1. The text below is about one of the most popular devices. Look through the text and think of a more appropriate heading for it. 2. Read the text carefully and find the phrases that mean:  portable indicating device  wire connected to the back panel  was devised in the early…  the most important (prevailing) type  detected changes in position  saves energy  wired mouse  electrical wire 19

 wireless mice  IR or radio-frequency technologies  the main button  to call a list of options 3. Is there anything in the text that you find particularly interesting or that you didn’t know before? What is it? 4. Note down all the facts connected with different periods of mice development and tell the rest of the class about them. 5. The last sentences of the text have been blanked out. What do you think they can be?

Input system A mouse is a hand-held pointing device used in computing. It is designed to sit under one hand of the user so as to detect movement. It usually has buttons and/or other devices which allow the user to perform different system-dependent operations. Douglas Engelbart of Stanford Research Institute invented the mouse pointing-device in 1963. This mouse used 2 gear-wheels perpendicular to each other. The name “mouse” was derived from the resemblance of early models to the rodent with the same name. These early models had a cord attached to the rear part of the device which looked like the tail of the mouse. Since those early days, several types of mice have evolved. One of these types is the mechanical mouse. The so-called ball mouse was invented in the early 1970s and became the predominant form used with personal computers throughout the 1980s and 1990s. Another type of mechanical mouse had two plastic “feet” on the bottom which sensed movement. Optical mice which used a light-emitting diode and photodiodes to detect movement were developed in the early 1980s. Due to its ability to embed more powerful image processing chips inside, the mouse was able to detect motion on a wide variety of surfaces, which also eliminated the need for a special mouse-pad. Nowadays, optical mice work by using an optoelectronic sensor to take pictures of the surface on which the mouse operates. Laser mice came out as early as 20

1998. In 2004, Logitech and Agilent Technologies introduced a laser mouse that used a small laser, which increased the resolution of the image taken by the mouse. Laser mice are wireless, which conserves power. 3D mouse was introduced in the late 1990s. It was wireless and was worn on a ring around a finger. It was discontinued because it did not provide sufficient resolution. Cabled mice typically use a thin electrical cord to transmit their input. Cordless mice transmit data through infrared radiation or radio. The mouse’s buttons have changed very little over the years, varying mostly in shape, number and placement. Most mice usually have between one and three buttons. Two-button mice are the most common. The primary button is located on the left hand side of the mouse, for the benefit of right-handed users. The second button is usually used to invoke a contextual menu in the computer’s software user interface, and is located on the right side.

Text 8 1. The text “Computer Software” includes a number of subheadings. Look through them and say what those parts of the text that go with them might be about. 2. Here are key words and expressions from two parts of the text. Read the text and find the parts these expressions are from. How do the words fit together? а) free of charge, downloading, to try out the program, a request for payment, distribution license. б)to store software, loaded into RAM, machine language, processor instructions, sequence of instructions, high-level languages, compiled or interpreted, assembly language, computer science, difference engine. 3. Computer software is various. Can you think of some kinds of it? Read the proper part of the text to find the answer. 4. Did you find any new or interesting facts in the text? Share them with the rest of the class. 21

Computer software Software, consisting of programs, enables a computer to perform specific tasks, as opposed to its physical components (hardware) which can only do the tasks they are mechanically designed for. The term includes application software such as word processors which perform productive tasks for users, system software such as operating systems, which interface with hardware to run the necessary services for user-interfaces and applications, and middleware which controls and coordinates distributed systems. Relationship to computer hardware Computer software is so called in contrast to computer hardware, which encompasses the physical interconnections and devices required to store and execute (or run) the software. In computers, software is loaded into RAM and executed in the central processing until. At the lowest level, software consists of a machine language specific to an individual processor. A machine language consists of groups of binary values signifying processor instructions (object code), which change the state of the computer from its preceding state. Software is an ordered sequence of instructions for changing the state of the computer hardware in a particular sequence. It is usually written in high-level programming languages that are easier and more efficient for humans to use (closer to natural language) than machine language. High-level languages are compiled or interpreted into machine language object code. Software may also be written in an assembly language, essentially, a mnemonic representation of a machine language using a natural language alphabet. Assembly language must be assembled into object code via an assembler. Types Practical computer systems divide software systems into three major classes: system software, programming software and applications software, although the distinction is arbitrary, and often blurred. 22

System software helps run the computer hardware and computer system. It includes operating systems, device drivers, diagnostic tools, servers, utilities and more. The purpose of system software is to insulate the application program as much as possible from the details of the particular computer complex being used, especially memory and other hardware features, and such accessory devices as communications, printers, readers, displays, keyboards, etc. Programming software usually provides tools to assist a programmer in writing computer programs and software using different programming languages in a more convenient way. The tools include text editors, compilers, interpreters, linkers, debuggers, and so on. An Integrated Development Environment (IDE) merges those tools into a software bundle, and a programmer may not need to type multiple commands for compiling, debugging, tracing, etc., because the IDE usually has an advanced graphical user interface, or GUI. Application software allows end users to accomplish one or more specific tasks. Typical applications include industrial automation, business software, educational software, medical software, databases, and computer games. Businesses are probably the biggest users of application software. It is used to automate all sorts of functions. Application software is often purchased separately from computer hardware. Sometimes applications are bundled with the computer, but that does not change the fact that they run as independent applications. Applications are almost always independent of the operating system, though they are often tailored for specific platforms. Most users think of compilers, databases, and other “system software” as applications. License Software license gives the user the right to use the software in the licensed environment, some software comes with the license when purchased off the shelf, or OEM license when bundled with hardware. Software can also be in the form of freeware or shareware. 23

Freeware Freeware is copyright computer software which is made available for use free of charge, for an unlimited time, as opposed to shareware where the user is required to pay (e.g. after some trial period or for additional functionality). Authors of freeware often want to “give something to the community”. But they also want credit for their software and to retain control of its future development. Sometimes when programmers decide to stop developing a freeware product, they will give the source code to another programmer or release the product’s source code to the public as free software. Shareware Shareware is a marketing method for computer software. Shareware program is typically obtained free of charge, either by downloading from the Internet or on magazine cover-disks. A user tries out the program, and thus shareware has also been known as “try before you buy”. A shareware program is accompanied by a request for payment, and the software’s distribution license often requires such a payment.

Text 9 1. Look at the heading of the text below and decide the extension to what part of the previous text it might be. 2. Read the text, find out what it describes and think of a more appropriate heading. 3. Analyse the overall structure of the text and classify ideas into main topics and details. Put the information down into your copy-book as a plan. 4. What do you think the purpose of this text is? Give reasons for your opinion. 1) to show the difference between types of software; 2) to encourage people to use OS; 24

3) to compare OSs; 4) to show details about OS; 5) to describe purpose of OS. 5. Summarize the text according to your plan.

System software The concept of an operating system (abbreviated OS) is a difficult one to explain. In essence, an operating system is a program which supervises a computer, and which is necessary to make the computer run efficiently enough to be of practical use. The actual computer machinery (the “hardware”) and the programs used in individual application (the “application software”) are not enough in themselves to make the computer run easily. In order for an instruction to be transmitted to the computer and for the computer to carry out that instruction well, a program which supervises the computer is also needed. A good analogy is a company or government department in which it is not enough to have only the people who do the actual work; administrators to run the organization are also needed. There are different types of operating systems for different purposes and computer systems. Many of them pretend to have the following characteristics: 1. Global. 2. Aimed at multiple users. 3. Interactive. 4. Time sharing. 5. Multi-programming. Let us now examine what these terms mean. 1. A global operating system is not intended only for one specialized use, but can be used in many different applications. On one occasion it might be used for office automation, on another occasion for controlling experimental apparatus, and on still another occasion for developing new programs. 25

2. A multi-user system permits a number of different users to use the computer at the same time, permits a number of terminals to be connected to one computer. Each user has exclusive use of one terminal from which he or she gives the computer instructions. When a user inputs an instruction from a terminal, an answer comes back from the computer immediately. 3. An interactive system permits a “conversation” between the user and the CPU. This interaction may be displayed on a CRT (cathode ray tube, which is similar to a television screen), or it may be printed out on paper by a teletypelike printer. 4. Time sharing means that when two or more jobs are done on the computer at the same time, a small amount of CPU time is given to each job in succession. The computer does only a little of each job at a time. The operating system has to keep track of how far along each job is and start the work from that point when the job’s turn comes up. The rate at which a human being can feed input into a computer is very slow compared to the rate at which the computer can process it. In the time it takes the human to get his input typed in, the computer can do other work and then get back to him. This means that any one user does not have to worry about being made to wait very long, and it eliminates the waste of CPU time that would occur without time sharing. Time sharing system is sometimes abbreviated to TSS. 5. Multi-programming concept is based on user’s jobs and computer tasks. From the viewpoint of a computer (strictly speaking, a CPU), a task is a work unit. From a user’s viewpoint, a work unit is a job (program) or a command. One job consists of one task or several tasks, and one task may invoke other tasks in turn. A word “process” is used in the same sense as a task. A multi-programming (or multi-job) system permits a single user to run several programs (jobs) at the same time. A user can create another job before he completes the previous job.

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Text 10 1. Read through the text below quickly and say whether you agree with its heading. 2. Define the topics of all the paragraphs by their first sentences. Which paragraphs are about OS and which – about files? 3. Read the text carefully. Where would you divide the text into logical parts? Explain why? 4. These are expressions from the text. Expand them into statements denoting ideas from the text.  interface between the hardware and software  allocation and usage of hardware resources  different operating systems  a file folder in a desk drawer  a unique name  filenames and directories  working directory  small or capital letters  process personal and business information  keep backup copies of valuable information 5. Read the text again and describe it in outline.

Operating systems and files An OS performs basic tasks on your computer, acting as an interface between the hardware and software on the system. Its primary purpose is to support the programs that perform tasks on your computer, such as word processing, e-mail, and database management. The OS is the software that controls the allocation and usage of hardware resources such as memory, central processing unit (CPU) time, disk space, and peripheral devices. The OS is the foundation on which applications are built, and 27

provides a software platform on top of which other programs can run. Every computer must have an OS to function, even if it is simply the boot files from DOS or Windows. Different operating systems will use different file systems to access the storage media and keep track of the locations in which data has been stored; the file system is the way the OS organizes and accesses the files on a disk. Being a collection of information, a file on your disk can be compared to a file folder in a desk drawer. For example, file folders might contain business letters from clients and important memos from associates. File on your disk could also contain business letters and memos. All programs, texts and data on your disk reside in files and each file has a unique name. You refer to files by their filenames. You create a file each time you enter and save data or text at your terminal. Files are also created when you write programs and save them on your disks. The names of files are kept in directories on a disk. These directories also contain information about the size of the files and the dates they were created and updated. The directory you are working in is called your working directory. The name of a typical MS-DOS file looks like this: newfile.doc. The name of the file consists of two parts. The filename is newfile and the filename extension is .doc. A filename can be from 1 to 8 characters long. The filename extension is optional, and can be three or fewer characters. You can type any filename in small or capital letters. Directory information (name, size, date and time) about the file newfile.doc is displayed on your screen. If drive A is the default drive, MS-DOS automatically searches the disk in drive A for the filename new file; so it is not necessary to type the drive name. A drive name is needed if you want to tell MS-DOS to look through a different drive to find a file. Your filenames will probably be made up of letters and numbers, but other characters are also allowed. Valid characters for filename extensions are the same as those for filenames. MS-DOS treats some devices names specially, and certain three-letter names are reserved for the names of these devices. These three-letter names cannot be used as filenames, but they can be used as extensions. MS-DOS is powerful and useful 28

tool when you process personal and business information because with any computer errors can occur and the information may be misused. If you are doing work that cannot be replaced or requires a high level of security, you should take steps to ensure that your programs are protected from being used, modified or even deleted by other users. Simple measures – such as: removing your disks when they are not in use, keeping backup copies of valuable information, and installing your equipment in a secure facility – can help you to keep your files safe.

Text 11 1. Look quickly over the text “Malicious Software (Malware)”. What type of malware does the largest part of the text describe? 2. Imagine someone knows nothing about computer viruses. Think of some useful vocabulary items for them to learn and put them down into your copy-book. Be ready to explain what they mean. 3. Find in the text and translate those parts which refer to the history of computer viruses. 4. Summarize the text.

Malicious software (Malware) Malware is a broad category of software designed to infiltrate or damage a computer system. Types of malware include spyware, adware, Trojan horses, worms, and true viruses. While modern anti-virus software works to protect computers from this range of threats, computer viruses make up only a small subset of malware. A computer virus is a computer program that can copy itself and infect a computer without permission or knowledge of the user. The original may modify the copies or the copies may modify themselves, as occurs in a metamorphic virus. A virus can only spread from one computer to another when its host is taken to the uninfected computer, for instance by a user sending it over a network or carrying it on a remov29

able medium such as a floppy disk, CD, or USB drive. Additionally, viruses can spread to other computers by infecting files on a network file system or a file system that is accessed by another computer. Viruses are sometimes confused with computer worms and Trojan horses. A worm, however, can spread itself to other computers being transferred as part of a host. A Trojan horse is a file that is harmless until executed. In contrast to viruses, Trojan horses do not insert their code into other computer files. Many personal computers are now connected to the Internet and to local-area networks, facilitating their spread. Today’s viruses may also take advantage of network services such as the World Wide Web, e-mail, and file sharing systems to spread, blurring the line between viruses and worms. Furthermore, some sources use an alternative terminology in which a virus is any form of self-replicating malware. The term comes from the term virus in biology. A computer virus reproduces by making, possibly modified, copies of itself in the computer’s memory, storage, or over a network. This is similar to the way a biological virus works. Some viruses are programmed to damage the computer by damaging programs, deleting files, or reformatting the hard disk. Others are not designed to do any damage, but simply replicate themselves and perhaps make their presence known by presenting text, video, or audio message. Even these benign viruses can create problems for the computer user. They typically take up computer memory used by legitimate programs. As a result, they often cause erratic behavior and can result in system crashes. In addition, many viruses are bugridden, and these bugs may lead to system crashes and data loss. There are many viruses operating in the Internet today, and new ones are discovered every day. The first PC virus was a boot sector virus called Brain, created in 1986 by two brothers from Pakistan. The brothers reportedly created the virus to deter pirated copies of software they had written. Before computer networks became widespread, most viruses spread on removable media, particularly floppy disks. In the early days of the personal computer, many users regularly exchanged information and programs on flop30

pies. Some viruses spread by infecting programs stored on these disks, while others installed themselves into the disk boot sector, ensuring that they would be run when the user booted the computer from the disk. Traditional computer viruses emerged in the 1980s. Since the mid-1990s, macro viruses have become common. Most of these viruses are written in the scripting languages for Microsoft programs such as Word and Excel. These viruses spread in Microsoft Office by infecting documents and spreadsheets. Since Word and Excel were also available for Mac OS, most of these viruses were able to spread on Macintosh computers as well. Most of these viruses did not have the ability to send infected e-mail. Those viruses which did spread through e-mail took advantage of the Microsoft Outlook COM interface. A virus may also send a web address link as an instant message to all the contacts on an infected machine. If the recipient, thinking the link is from a friend (a trusted source) follows the link to the website, the virus at the site may be able to infect this new computer and continue propagating.

Text 12 1. Read the text below, consider it as a whole and make up its plan according to the overall structure of the text. 2. Read the text more carefully and choose one answer (a, b) for questions I–VIII. I.Who is personally responsible for the running of the Internet? a. Different countries claim responsibility for the Internet. b. No person is actually responsible for the upkeep and running the Net. II.What does the remote server provide to the users? a. Distant server machine serves the user’s machine with collections of information for the computer. b. Remote server machine provides new types of PC and hardware to the user’s local client machine. 31

III.Why is the Web the most rapidly growing part of the Internet? a. Because it supports hypertext to access some Internet protocols. b. Because it supports modern advanced technologies. IV.What is Usenet News? a. It’s a piece of information received by millions of computer users. b. It’s a world-wide notice-board system of exchanging information on different topics. V.How can IRC be accessed? a. Through a special software program. b. By using a special type of a computer system. VI.How quick is e-mail? a. Messages can arrive within some minutes or so. b. Information is received in some seconds. VII.What may be incorporated into Telnet programs? a. Different things, including multimedia and graphics. b. Only text. VIII.Why are tags used with HTML? a. For document formatting. b. For adding new tags to the upgraded variants of the language. 3. Shorten the material of the text and restate main ideas leaving out details. Use a prepared plan of the text to help you.

The Internet The Internet is a computer network made up of thousands of networks worldwide. No one knows exactly how many computers are connected to the Internet. It is certain, however, that they number millions and millions. No one is in charge of the Internet. There are organizations which develop technical aspects of this network and set standards for creating applications on it, but no 32

governing body is in control of it. The Internet backbone, through which Internet traffic flows, is owned by private companies. All computes on the Internet communicate with one another using the Transmission Control Protocol/Internet Protocol suite, abbreviated to TCP/IP. Computers on the Internet use client/server architecture. This means that the remote server machine provides file and services to the user’s local client machine. Software can be installed on a client computer to take the latest access technology. An Internet user has access to a wide variety of services: electronic mail, file transfer, vast information resources, interest group membership, interactive collaboration, multimedia displays, real-time broadcasting, breaking news, shopping opportunities, and much more. The Internet consists primarily of a variety of access protocols. Many of these protocols feature programs that allow users to search for and retrieve material made available by the protocol. Components of the Internet World Wide Web The World Wide Web (abbreviated as the Web or WWW) is a system of Internet servers that supports hypertext to access several Internet protocols on a single interface. Almost every protocol type available on the Internet is accessible on the Web. This includes e-mail, FTP, Telnet, and Usenet News. In addition to these, the World Wide Web has its own protocol: Hypertext Transfer Protocol, or HTTP. The operation of the Web relies primarily on hypertext as its means of information retrieval. Hypertext is a document containing words that are called links selectable by the user. A single hypertext document can contain links to many documents. In the context of the Web, words or graphics may serve as links to other documents, images, video, and sound. Links may or may not follow a logical path, as each connection is programmed by the creator of the source document. Overall, the Web contains a complex virtual web of connections among a vast number of documents, graphics, sounds. 33

Because of the Web’s ability to work with multimedia and advanced programming languages, the Web is the fastest-growing component of the Internet. FTP FTP stands for File Transfer Protocol. This is both a program and the method used to transfer files between computers. Anonymous FTP is an option that allows users to transfer files from thousands of host computers on the Internet to their personal computer account. FTP sites contain books, articles, software, games, images, sounds, multimedia, course work, data sets, and more. Whenever you download software from a Web site to your local machine, you are using FTP. Usenet News Usenet News is a global electronic bulletin board system in which millions of computer users exchange information on a vast range of topics. The major difference between Usenet News and e-mail discussion groups is the fact that Usenet messages are stored on central computers, and users most connect to these computers to read or download the messages posted to these groups. This is different from e-mail distribution, in which messages arrive in the electronic mailboxes of each list member. Usenet itself is a set of machines that exchanges messages, or articles, from Usenet discussion forums, called newsgroups. Usenet administrators control their own sites, and decide which (if any) newsgroups to sponsor and which remote newsgroups to allow into the system. There are thousands of Usenet newsgroups in existence. While many are academic in nature, numerous newsgroups are organized around recreational topics. Much serious computer-related work takes place in Usenet discussions. A small number of e-mail discussion groups also exist as Usenet newsgroups. Chat & instant messaging 34

Chat programs allow users on the Internet to communicate with each other by typing in real time. They are sometimes included as a feature of a Web site, where users can log into the “chat room” to exchange comments and information about the topics addressed on the site. Chat may take other, more wideranging forms. For example, America Online is well known for sponsoring a number of topical chat rooms. Internet Relay Chat (IRC) is a service through which participants can communicate to each other on hundreds of channels. These channels are usually based on specific topics. While many topics are frivolous, substantive conversations are also taking place. To access IRC, you must use an IRC software program. A variation of chat is the phenomenon of instant messaging. With instant messaging, a user on the Web can contact another user currently logged in and type a conversation. Most famous is America Online’s Instant Messenger. ICQ, MSN, and Yahoo also offer chat programs. E-mail Electronic mail, or e-mail, allows computer users locally and worldwide to exchange messages. Each user of e-mail has a mailbox address to which messages are sent. Messages sent through e-mail can arrive within a matter of seconds. A powerful aspect of e-mail is the option to send electronic files to a person’s e-mail address. Non-ASCII files, known as binary files, may be attached to e-mail messages. These files are referred to as MIME attachments. MIME stands for Multimedia Internet Mail Extension, and was developed to help email software handle a variety of file types. For example, a document created in Microsoft Word can be attached to an e-mail message and retrieved by the recipient with the appropriate e-mail program. Many e-mail programs, including Eudora, Netscape Messenger, and Microsoft Outlook, offer the ability to read files written in HTML, which is itself a MIME type. 35

Telnet Telnet is a program that allows you to log into computers on the Internet and use online databases, library catalogs, chat services, and more. There are no graphics in Telnet sessions, just text. To Telnet to a computer, you must know its address. This can

consist of words (locis.loc.gov) or numbers

(140.147.254.3). Some services require you to connect to a specific port on the remote computer. In this case, type the port number after the Internet address. Example: telnet nri.reston.va.us 185. HTML Producing hypertext for the Web is accomplished by creating documents with a language called Hypertext Markup Language, or HTML. With HTML, tags are placed within the text to accomplish document formatting, visual feature such as font size, italics and bold, and the creation of hypertext links. Graphics and multimedia may also be incorporated into an HTML document. HTML is an evolving language, with new tags being added as each upgrade of the language is developed and released. For example, visual formatting features are now often separated from the HTML document and placed into ‘Cascading Style Sheets’ (CSS). This has several advantages – including the fact that an external ‘style’ sheet can centrally control the formatting of multiple documents. The World Wide Web Consortium (W3C), led by Web founder Tim Berners-Lee, coordinates the efforts of standardizing HTML. The W3C now calls the language XHTML and considers it to be an application of the XML language standard. The World Wide Web consists of files, called pages or home pages, containing links to documents and resources throughout the Internet.

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Part III. After you read 1. Look again through all the texts you have read and choose subject(s) that is (are) closest to you and most interesting. Write a message about it for a bulletin board. 2. Bill Gates once said: “The Internet … will open the doors to most of the world’s information.” What problems will there be or do already exist? What do you think? 3. Talk about possible uses of the Internet. Which of these is most interesting to you? Why? e-mail, chat, games, shopping, information 4. Work with a partner. Talk about one of these subjects: Computers and … a) families

b) businesses

c) friends

d) countries

Phrases-cliché used to summarize the texts The text deals with the problem of … The subject-matter of the text is … The most important questions touched upon in this text are … It is specially noted that … The text (information) is of great help (interest) to … The most essential point is … The author is (is not) right in saying that … The author’s point of view is … The text gives a detailed analysis of … As the title implies, the text describes … In the end we come to the conclusion … I can conclude by saying … As a final point, I’d like to note (say) … To sum up, I can say … 37

References 1. Gates B. The Road Ahead / B.Gates et al. – N.Y. : Viking, 1995. – 286 p. 2. Grussendorf M. English for Presentations / M. Grussendorf. – English for Presentations. – Oxford : University Press, 2007. – 80 p. 3. O’Dell F. English Panorama. Student’s Book / F.O’Dell. – English Panorama. Student’s Book. – Cambridge : University Press, 1997. – 176 p.

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Contents Введение ........................................................................................................... 3 Part I. Before you read ...................................................................................... 3 Part II. Practise reading the texts ...................................................................... 4 Part III. After you read ..................................................................................... 37 Phrases-cliché used to summarize the texts ................................................... 38 References ......................................................................................................... 39

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Учебное издание

COMPUTERS TODAY Учебно-методическое пособие для вузов

Составитель: Гурьянова Вера Ивановна

Редактор Л.М. Носилова

Подписано в печать 16.03.09. Формат 60×84/16. Усл. печ. л. 2,3 Тираж 100 экз. Заказ 431. Издательско-полиграфический центр Воронежского государственного университета. 394000, г. Воронеж, пл. им. Ленина, 10. Тел. 208-298, 598-026 (факс) http://www.ppc.vsu.ru; e-mail: [email protected] Отпечатано в типографии Издательско-полиграфического центра Воронежского государственного университета. 394000, г. Воронеж, ул. Пушкинская, 3. Тел. 204-133 40