Part 1 The computer icon

Part 1 The computer



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UNIT 2


^ History of computers


When you read the following text, you will probably meet words and expressions that are new to you. First try to understand their meaning from the context - read the same passage a few times. When you have read the hole text, check new words in a dictionary. Those words in bold typeface are explained in the Glossary at the end of this book.


1. Let us take at the history of the computers that we know today. The very first calculating device used was the ten fingers of a man’s hands. This, in fact, is why today we still count in tens and multiples of tens. Then the abacus was invented, a bead frame in which the beads are moved from left to right. People went in using some form of abacus well into the 16 th century and it is still being used in some parts of the world because it can be understood without knowing how to read.


2. During the 17 th and 18 th centuries many people tried to find easy ways of calculating. J.Napier, a Scotsman, devised a mechanical way of multiplying and dividing, which is how the modern slide rule works. Henry Briggs used Napier' s ideas to produce logarithm tables which all mathematicians use today. Calculus another branch of mathematics, independently invented by both Sir Isaac Newton, an Englishman, and Leibnitz, a German mathematician.


3. The first resl calculating machine appeared in 1820 as the result of several people' s experiments. This type of machine, which saves a great deal of time and reduces the possibility of making mistakes, depends on р series of ухя4юющхф gear wheels. In 1830 Charles Babbage, an Englishman, desigJied р macliine that was called “The analytical engine”. This machine, which Babbage showed at the Paris Exhibition in 1855, was an attempt to cut out the human being altogether, except for providing the machine with the necessary facts about the problem to be solved. He never finished this work, but many of his ideas were the bases for building today's computers.


4. In 1930, the first analog computer was built by an American named Vannevar Bush. This devise was used in World War II to help aim guns. Mark I, the name given to the first digital computer, was completed in 1944. The men responsible for this invention were Professor Howard Aiken and some people from IBM. This was the first machine that could figure out long lists of mathematical problems, all at р very fast rate. In 1946 two engineers at the University of Pennsylvama, J. Eckert and J. Mauchly, built the first digital computer using parts called vacuum tubes. They named their new invention ENIAC. Another important advancement in computers came in 1947, when John von Newmann developed the idea of keeping instructions for the computer inside the computer's memory.


5. The generation of computers, which used vacuum tubes, came out in 1950. Univac1 is an example of these computers which could perform thousands of calculations per second. In 1960, the second generation of computers was developed and these could perform work ten times faster then their predecessors. The reason for this extra speed was the use of transistors instead of vacuum tubes. Second generation computers were smaller, faster and more dependable than first generation computers. The first generation computers appeared on the market in 1965. These computers could do р million calculations р second, which 1000 times au many as first generation computers. Unlike second generations computers have now arrived, and the integrated circuits that are being developed have been greatly reduced in size. This is due microminiaturization, which means that the circuits are much smaller than before; as many as 1000 tiny circuits now fit on to a single chip. A chip is р square or rectangular piece of silicon, usually from 1/10 to 1/5 inch, upon which several layers of an integrated circuit are etched or imprinted, after which the circuits is encapsulated in plastic, ceramic or metal. Fourth generation computers are 50 times faster than third generation computers and can complete approximately one million instructions per second.


6. At the rate computer technology is growing, today' s computers might be obsolete by 1985 and most certainly by 1990. It has been said that it transport technology had developed as rapidly as computer technology, a trip across the Atlantic Ocean today would take a few seconds.

Exercises

1. Main idea

Which statement best expresses the main idea of text? Why did you eliminate the other choices?

1. Computers, as we know them today, have gone through many changes.

2. Today' s computer probably won' t be around for long.

3. Computers have had a very short history.


^ 2.Understanding the passage

Decide whether the following statements are true or false (T/F} by referring to the information in the text. Then make the necessary changes so that the false statements become true.

T F

__ __1 The abacus and the fingers are two calculating devices still in use today.

__ __2 The slide rule was invented hundreds of years ago.

__ __3 During the early 1880, many people worked on inventing р mechanical calculating machine.

__ __4 Charles Babbage, an Englishman, could well be called the father of computers.

__ __5 The first computer was invented and built in the USA.

__ __6 Instructions used by computers have always been kept inside the computers memory.

__ __7 Using transistors instead of vacuum tubes did nothing to incresse the speed at which calculations were done.

__ __8 As computers evolved, their size decreased and their dependability increased.

__ __9 Today' s computers have more circuits than previous computers.

__ __10 Computer technology has developed to a point from which new developments in the field will take a long time to come.


^ 3. Locating information

Find the passages in the text where the following ideas are expressed . Give the line references.


___1 During the same period in history, logarithm tables and calculus were developed.

___2 It wasn' t until the 19 th century that р calculating machine was invented which tried to reduce manpower.

___3 Integrated circuitry has further changed computers.

___4 People used their fingers to count.

___5 The computers of the future may be quite different from those in use today.

___6 Today' s computer circuits can be put on р chip.

___7 Then an instrument with beads was invented for counting before р mechanical way for multiplying and dividing was devised.

___8 Transistors replaced vacuum tubes.


^ UNIT 3

Characteristics


When you read the following text, you will probably meet words and expressions that are new to you. First try to understand their meaning from the context - read the same passage р few times. When you have read the hole text, check new words in a dictionary. Those words in bold typeface are explained in the Glossaiy at the end of this book.


1 Computers are machines designed to process, electronically, specially, prepared pieces of information which are termed data. Handing or manipulating the information that has been given to the computer, in such ways as doing calculations, adding information or making.

2 All computers have several characteristics in common, regardless of make or design.

Information, in the form instructions and data, is given to the machine; after which the machine acts on it, and a result is then returned. The information presented to the machine is the input; the internal manipulative operations, the processing; and the result, the output. These three basic concepts of input, processing, output occur in almost every aspect of human life whether at work or at play. For example, in clothing manufacturing, the input is the pieces of cut cloth, the processing is the sewing together of these pieces, and the output is the finished garment.




3 Figure 3.1 shows schematically the fundamental hardware components in a computer system the centerpiece is called either the computer, the processor, or, usually, the central processing unit (CPU). 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. Attached to the CPU are the various peripheral devices such as card readers and keyboards (two common examples of input devices). When data of programs need to be saved for long periods of time, they are stored on various secondary memory devices of storage devices such as magnetic tapes or magnetic disks.

4 Computers have often been thought of as extremely large adding machines, but this is a very narrow view of their function. 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 has no known limit on the kinds of things it can do ; its versatility is limited only by the imagination of those using it.

5 In the late 1950 and early 1960 when electronic computers of the kind in use today were being developed, they 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 that computing power has become portable, more compact, and cheaper.

6 In only a very short period of time, computers have greatly changed the way in which many kinds of work are performed. Computers can remove many of the routine and boring tasks from our lives, thereby leaving us with more time for interesting, creative work. It goes without saying that computers have created whole new areas of work that did not exist before their development.

Exercises

^

1 Main idea


Which statement or statements best expresses the main idea of the text? Why did you eliminate the other choices?

___1 Computers have changed the way in which we live.

___2 All computers have an input, р processor, an output and р storage device.

___3 Computers have decreased man' s workload.

___4 All computers have the same basic hardware components.

^ 2. Understanding the passage

Decide whether the following statements are true or false (T/F} by referring to the information in the text. Then make the necessary changes so that the false statements become true.

T F

__ __1 All information to be processed must be prepared in such a way that the computer will understand it.

__ __2 Because of the complex electronic circuitry of р computer, data can be either stored or moved about at high speeds.

__ __3 Not all computers can process data given to them and produce results.

__ __4 The basic concepts of data processing are restricted to computers alone.

__ __5 The processor is the central component of р computer system.

__ __6 All other devices used р computer system are. attached to the CPU.

__ __7 Memory devices are used for storing information.

__ __8 Computers are very much restricted in what they can do.

__ __9 Computers today cost less, are smaller, and need fewer people to operate them than in the past.

__ __10 Computers haven' t changed our working conditions very much.


^ 3. Locating information

Find the passages in the text where the following ideas are expressed . Give the line references.

___1 All computers are basically the same.

___2 Then arithmetic and/or decision-making operations are performed.

___3 Computers are limited by man’s imagination more than anything else.

___4 All the equipment used in р computer system is the hardware.

___5 Computers are electronic machines used for processing data.

___6 If programs or data need to be kept for р long time. they are stored on tapes or disks.

___7 First the computer accepts data.

___8 Finally, new information is presented to the user.

^

4 Contextual reference


Look back at the text and find out what the words in bold typeface refer to.

1 which are termed data

2 or moving them

3 the machine acts on it

4 they are stored on

5 it is not р single-purpose machine

6 the kinds of things it can do

7 of those using it

8 they were very expensive to own

9 moreover, their size and reliability

10 that did not exist

^

4 Understanding words


Refer back to the text and find synonyms (i.e. words with a similar meaning) for the following words.

1 called

2 tremendous

3 ideas

4 react

5 take away

6 taken away


Now refer back to the text and find antonyms (i.e. words with an opposite meaning) for the following words.


1 wide

2 limited

3 immovable

4 after


UNIT 4

^
Computer capabilities and limitations


When you read the following text, you will probably meet words and expressions that a new to you. First try to understand their meaning from the context - read the same passage a few times. When you have read the hole text, check new words in a dictionary. Those words in bold typeface are explained in the Glossary at the end of this book.


1 Like all machines, a computer needs to be directed and controlled in order to perform р task successfully. Until such time as 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 recognized, its usefulness cannot be thoroughly understood.

2 In the first place, 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.

3 Secondly, computers can process information at extremely rapid rates. For example, modern computers can solve certain classes of arithmetic problems millions of times faster than a skilled mathematician. Speeds for performing decision-making operations are comparable to those for arithmetic operations but input-output operations, however, involve mechanical motion and hence require more time. On a typical computer system, cards are read at an average speed of 1000 cards per minute and as many as 1000 lines can be printed at the same rate.

4 Thirdly, computers may be programmed to calculate answers to whatever level of accuracy is specified by the programmer. In the spite of newspaper headlines such as "Computer Fails" 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.

5 In the fourth place, general-purpose computers can be programmed to solve various types of problems because of 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 р number of little problems - one after another.

6 Finally, a computer, unlike a human being, has no intuition. A person may suddenly find the answer to р problem without working out too many of the details, but a computer can only proceed as it has been programmed to.

7 Using the very limited capabilities possessed by all computers, the task of producing a university payroll, for instance, can be done quite easily. The following kinds of thing need be done for each employee on the payroll. First: Input information about the employee such as wage rate, hours worked, tax rate, unemployment insurance, and pension deductions. Second: Do come simple arithmetic and decision making operations. Third: Output a few printed lines on a cheque. By repeating this process over and over again, the payroll will eventually be completed.

Exercises
^

1 Main idea


Which statement or statements best expresses the main idea of the text? Why did you eliminate the other choices?

___1 The most elaborate of computers must be programmed in order to be useful.

___2 It is important to know what a computer can and cannot do.

___3 A computer is useless without a programmer to tell it what to do.

^

2 Understanding the passage


Decide whether the following statements are true or false (T/F) by referring to the information in the text. Then make the necessary changes so that the false statements become true.

T F

__ __1 A computer cannot do anything until it has been programmed.

__ __2 A computer is р useless machine if its capabilities and limitations are unknown.

__ __3 A computer can repeat the same operation over and over again forever if permitted.

__ __4 The speed at which different computer components function is considered to be one of the limitations of a computer.

__ __5 Computers do not usually make mistakes unless they break down.

__ __6 A computer can think and solve problems by itself.

__ __7 A computer is a single-purpose machine in that it cannot be programmed to solve various types of problems.

__ __8 Computers can solve big problems by following a series of simple steps.

__ __9 A computer usually solves problems by doing some mathematical and decision making operations.

__ __10 Computers are used because they are fast and extract.

^

3 Locating information


Find the passages in the text where the following ideas are expressed . Give the line references.

1 A computer can do the same operation millions of times without stopping.

2 A computer must work out the details of a problem before reaching a solution.

^ 3 A computer needs to be told what to do.

4 Computers can solve all kinds of different problems.

5 Knowledge of a computer's capabilities and limitations is important.

6 A computer can process information very rapidly.

7 Computers are exact and dependable.

8 Input and output devices operate more slowly than the arithmetic and decision-making devices.

^

4 Contextual reference


Look back at the text and find out what the words in bold typefase refer to.


1 no matter how capable it is

2 to those for arithmetic operations

3 they are man-made machines

4 they sometimes malfunction

5 because of their flexibility

6 one after another

7 as it has been programmed to

8 the following kinds of things need to be done

9 by repeating this process

^

5 Understanding words


Refer back to the text and find synonyms (i.e. words with р similar meaning) for the following words.

1 job

2 comprehended

3 clever

4 cases

5 salary sheet


Now refer back to the text and find antonyms (i.e. words with an opposite meaning) for the following words.

6 basic

7 exceptional

8 run well

9 slowly

10 employer


^ 6 WORD FORMS

First choose the appropriate form of the words to complete the sentences. Then check the differences of meaning in your dictionary.


1 repetition, repeat, repetitive, repeatedly, repeating

a. A computer can do __________________operations without getting tired or bored .

b. There are some people who____________________ arrive late to class whenever they’re working on a program because they forget the time.

c. ___________________ , which can be a boring and unproductive task has been eliminated with the use of computers.

d. A computer can _____________________ the same operation over and over again accurately without becoming bored or tired.


2 comparison, compare, comparable, comparatively, comparative

a. Renting a computer isn’ t ____________________to owning one.

b. Computers can __________________numbers.

c. There is sometimes very little ______________________ to be made between two different brand-name microcomputers.

d. The difference in price of microcomputers from different manufactures can be ___________________ small.


^ 3 repairs, repaired, repairable, repair

a. When the computer is down it needs to be ______________________ .

b. Electronic equipment often takes a long time to _____________________ .

c. ____________________ to a computer system are often done by the same company who manufactured the system.


^ 4 accuracy, accurate, accurately

a. A computer is always________________ in its results if well prepared.

b. ___________________ is one of the advantages of using computers in research or a statistical analysis.

c. Computers can produce results quickly and _____________________ .


^ 7 a CONTENT REVIEW

__1 decision-making operations a. can solve different types of problems

__2 programmer b. all the equipment needed input, process and output information

__3 general-purpose computers c. those which compare numbers

__4 computer d. decides what the program is to be.


7 b CONTENT REVIEW

Decide which of the following statements are computer capabilities or limitations. (С or L in each box).

___1 directed and controlled

___2 must be told what to do

___3 capable of doing repetitive operations

___4 never gets bored or tired

___5 fast and careful

___6 input-output operations are slower

___7 very accurate and dependable

___8 man-made machine

___9 can solve different types of problems

___10 finds р solution after working out all the details

___11 can' t think for itself

___12 producing a payroll is an easy task

^

8 FOCUS REVIEW


Focus C Organizing information

On a separate sheet, organize the information in Unit 4, "Computer Capabilities and Limitations", under main idea(s), major details and minor details.


UNIT 5

Hardware and software

1. In order to use computers effectively to solve problems in our environment, computer systems 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.

2. 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 that direct the processing of data.




3. Figure 5.1 shows diagrammatically the basic components of computer hardware joined together in a computer system. The centerpiece is called 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 manipulation are performed, and to the internal memory in which data and instructions are stored during the actual execution of programs. The various peripherals, which include input output devices, various secondary memory devices, and so on, are attached to the CPU.

4. 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 system supplier as part of a computer product designed to answer a specific need in certain areas. These complete hardware/software products are called turnkey systems.

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

Exercises

^

1 Main idea


Which statement or statements best expresses the main idea of the text? Why did you eliminate the other choices?

1 Only hardware is necessary to make up a computer system.

2 Software alone doesn’t' constitute a computer system.

3 A computer system needs both hardware and software to be complete.


^ 2 UNDERSTAWDING THE PASSAGE

Indicate whether the following ideas are stated or not stated (S/NS) in the text.

S NS

__ __1 A system implies a good mixture of parts working together.

__ __2 Input and output devices operate more slowly than the decision-making devices.

__ __3 The control unit and the arithmetic-logical unit are part of the processor.

__ __4 The "computer" is the hardware.

__ __5 Software is the programs on cards, tapes and disks.

__ __6 The processor is usually referred to as the CPU.

__ __7 The word "computer" means the processor and the internal memory.

__ __8 Systems software is usually referred to as programs.

__ __9 Complete hardware/software products are called turnkey systems.

__ __10 Computers process specially prepared items of information.


3 Locating information

Find the passages in the text where the following ideas are expressed . Give the line references.


____1 The hardware consists of the physical devices of the computer.

____2 In order to solve problems, an appropriate computer system must be developed.

____3 The "computer" is the CPU and the internal memory.

____4 The success or failure of a computer system depends on the proper mixture of hardware and software.

____5 These are two parts to a computer system.

____6 Computer software can be divided into two parts.

____7 The software is the programs.

____8 The peripheral devices are attached to the CPU.


^ 4 Contextual references

Look back at the text and find out what the words in bold typeface refer to.


1 Computer systems may discussed in two parts

2 that are thought of

3 that control and coordinate

4 and that direct the processing

5 in which calculations

6 in which data and instructions

7 The former is often simply referred to

8 These, when brought into

9 provided along with

10 for which it was originally acquired


4 Understanding words

Refer back to the text and find  synonyms (i.e. words with a  similar meaning) for the following words.

1 developed

2 infers

3 joined

4 chosen

Now refer back to the text and find antonyms (i.e. words with an opposite meaning) for the following words.

5 segregated

6 useless

7 narrow

8 well


^ 6 WORD EORMS

First choose the appropriate form of the words to complete the sentences. Then check the differences of meaning in your dictionary.


1 integration, integrate, integrated, integrating

a. Some computer manufactures have __________________both input and output devices into one terminal.

b. The success of any computer system depends on the ____________________of all its parts to form a useful whole.

c. ______________ input and output devices into one peripheral has reduced the area needed for a computer installation.


^ 2 coordination, coordinate, coordinated, coordinating, coordinator

a. The control unit of a processor the flow of information between the arithmetic unit and the memory.

b. __________________ the many activities in a computer department is the job of the department head.

c. The________________ of a language institute has assistants to help him and may have access to a computer to help him with the _______________of the many programs, timetables, space and student result.


^ 3 diagram, diagrammatic, diagrammatically, diagrammed

a. Very often manufactures provide_________________ representation of the internal workings of a computer.

b. A_________________ is a drawing that shows how something is arranged rather than what it actually looks like.

c. A few ideas have been__________________ for you in this book.


^ 4 interchange, interchangeable, interchangeably, interchanged

a. The words "arithmetic-logic" and "arithmetic-logical" can be used__________________.

b. There is often an_________________ of ideas among computer scientists.

c. There is a big difference between an input and an output. These cannot be____________________.


^ 5 division, divide, divisible

a. It is often difficult for computer science students to___________________ proportionally between studying and programming.

b. There is always a _________________of labour within a computer company.

c. Are all numbers _________________by three?


^ UNIT 7

Microcomputers


1 Until the mid-l960s, digital computers were powerful, physical large and expensive. What was really needed thought, were computers of less power, a smaller memory capacity and without such a large array peripheral equipment. This need was partially satisfied by the rapid improvement in performance of the semi-conductor devices {transistors), and their incredible reduction in size, cost and power; all o which led to the development of the minicomputer or mini for shot. Although there is no exact definition of minicomputers, it is generally understood to refer to a computer whose mainframe is physically small, has a fixed word length between 8 and 32 bits and cost less than U.S. $100,000 for the central processor. The amount of primary storage available optionally in microcomputer system ranges from 32-512 Kbytes; however, some systems allow this memory to be expanded even further.

2 A large number of peripheral have been developed especially for use in systems built around minicomputers; they are sometimes referred to as miniperipherals. These include magnetic tape cartridges and cassettes, small disk units and a large variety of printers and consoles.

3 Many minicomputers are used merely for a fixed application and run only a single program. This is changed only when necessary either to correct errors or when a change in the design of the system is introduced. Since the operating environment for most minis is far less varied and complex than large mainframes, it goes without saying that the software and peripheral requirements differ greatly from those of a computer which runs several hundred ever-changing jobs a day. The operating systems of minis also usually provide system access to either a single user or to a limited number of users at a time.

4 Since many minis are employed in real-time processing, they are usually provided with operating systems that are specialized for this purpose. For example, most minis have an interrupt feature, which allows a program to be interrupted when they receive a special signal indicating that any one of a number of external events, to which they are a reprogrammed to respond, has occurred. When the interrupt occurs, the computer stores enough information about the job in process to resume operation after it has responded to the interruption. Because minicomputer system have been used so often in real-time applications, other aspects of their design have changed; that is, they usually possess the hardware capability to be connected directly to a large variety of measurement instruments, to analog and digital converters, to microprocessors, and ultimately, to an even larger mainframe in order to analyse the collected data.

^

1 Main idea


Which statement or statements best expresses the main idea of the text? Why did you eliminate the other choices?

1 Minicomputers are not as effec6ve as mainframes.

2 Minicomputers are useful as mainframes.

3 Minicomputers are not as big and expensive as mainframes.

4 Minicomputers will not be of any use in the future.


^ 2 UNDERSTANDING THE PASSAGE

Indicate whether the following ideas are stated or not stated (S/NS) in the text.

S NS

__ __1. The rapid development of transistors led to the development of minicomputers.

__ __2. A minicomputer is said to be very much the same as a mainframe.

__ __3. Special peripheral devices have been developed to go with minicomputers.

__ __4. Minicomputers can understand more than one computer language.

__ __5. Mainframe operating system usually provide access to a number of users as the same time.

__ __6. Minicomputers have specialized features because of the operations they execute.


UNlT 8

Microcomputers


1 The early 1970s saw the birth of the microcomputer, or micro for short. The central processor of the micro, called the microprocessor, is built as a single semiconductor device; that is, the thousands of individual circuit elements necessary to perform all the logical and arithmetic functions of a computer are manufactured as a single chip. A complete microcomputer system is composed of a microprocessor, a memory and peripheral equipment. The processor, memory and electronic controls of the peripheral equipment are usually put together on a single or on a few printed circuit boards. Systems using microprocessors can be hooked up together to do the work that until recently only minicomputer systems were capable of doing. Micros generally have somewhat simpler and less flexible instruction sets than minis, and are typically much slower. Different micros are available with 4-, 8- 12-, 16-bit word lengths. Similarly, minis are available with word lengths up to 32 bits. Although minis can be equipped with much larger primary memory sizes, micros are becoming more powerful and converging with microcomputer technology.

2 The extremely low once of micros has opened up entirely new areas of application for computers. Only 20 years or so ago, a central processing unit of medium capability sold for a few hundred thousands dollars, and now some microprocessors sell for as cheaply as $10. Of course, by the time you have a usable microcomputer system, the once will be somewhere between $500 and $10,000 depending on the display unit, secondary storage, and whatever other peripherals are needed.

3 The available range of microcomputer systems is evolving more rapidly than minicomputers. Because of their incredibly low price, it is now possible to use only a small fraction of the computer's capability in a particular system application and still be far ahead financially of any other way of getting the job done. For example, thousands of industrial robots are in use today, and the number is growing very rapidly as this relatively new industry improves the price and performance of its products by using the latest microcomputers.

4 Even thought the software available for most microcomputer system is very limited - more so than for minis - it does not discourage their use in the many high-volume, fixed applications for which programming is essentially a ”one shot deal” as is the case in the space shuttle program. In addition to their extensive use in control systems of all types, they are destined for many new uses from more complex calculators to automobile engine operation and medical diagnostics. They are already used in automobile emission control systems and are the basis of many TV game attachments. There is also a rapidly growing market for personal computers whose application potential in education is only just beginning to be exploited.

5 It would seem that the limits for microcomputer applications have by no means been reached. There are those who predict that the home and hobby computer markets will grow into a multi-billion dollar enterprise within a decade or so. It would also appear that performance of microprocessors could well increase ten-fold before 1990 while prices for micros could decrease by as much.


Exercises
^

1 Main idea


Which statement or statements best expresses the main idea of the text? Why did you eliminate the other choices?

1 Microcomputers will be everywhere in the future.

2 There are no limits to what microcomputers can do.

3 Microcomputers are cheap, reliable and efficient.

4 Microcomputers are far superior to minicomputers.


^ 2 UNDERSTANDING THE PASSAGE

Indicate whether the following ideas are stated or not stated (S/NS) in the text.

S NS

__ __1 Microcomputers were developed after minicomputers.

__ __2 The processor of a microcomputer is printed on a chip.

__ __3 A mainframe uses more power than a microcomputer.

__ __4 Microcomputers can do the work done by minicomputers.

__ __5 Microcomputers have the same memory capacity as minicomputers and can be hooked up to a variety of peripherals.

__ __6 Microcomputers are cheaper than minicomputers.

__ __7 Many different types of industries are using microcomputers to do their work.

__ __8 Microcomputers are now used in sophisticated toys and games.

__ __9 Because of microminiaturization, mainframes now occupy less space.

__ __10 By the end of this century microcomputers will be cheaper, better and probably usedin every aspect of life.


3 Locating information

Find the passages in the text where the following ideas are expressed. Give the line references.


___1. Microcomputers can do work that until quite was done by minicomputers.

___2. Microcomputers are mainly used for single-purpose jobs.

___3. The integrated circuitry of a microcomputer has been reduced to a chip.

___4. Microcomputer technology will continue to improve.

___5. Microcomputers are smaller, simpler and less flexible than minicomputers.

___6. Microcomputers are very recent development in computer technology.

___7. Microcomputer systems are increasing faster than minicomputers.

___8. In the future, microprocessors will be cheaper, and their capacity and performance will be greater.


4 Contextual references

Look back at the text and find out what the words in bold typeface refer to.


^ 1 that until recently

2 because of their incredibly low price

3 performances of its products

4 it does not discourage their use

5 for which programming is essentially

6 in addition to their extensive use

7 they are destined for many new uses

8 whose application potential

9 who predict that


UNIT 9

The central processing unit




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. Manufactures design the CPU to control and carry out the 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 memory and can store the results of manipulations back into the memory unit for later reference.

3 In digital computers the CPU can be divided into two functional units called the control unit 10 (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 systems, selects instructions and data from memory, interprets the 15 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 is 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 20 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 р console, where manual control operations can 25 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.

Exercises


1 Main idea

Which statement or statements best expresses the main idea of the text? Why did you eliminate the other choices?


___1. Main storage is not a part of the processor.

___2. The CPU is made up of the control unit, the arithmetic-logical unit and internal memory.

___3. The CPU is composed of the arithmetic-logical unit and control unit only.


^ 2 UNDERSTANDING THE PASSAGE

Indicate whether the following ideas are stated or not stated (S/NS) in the text.

T F

__ __1The 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 in 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.


^ 3 Locating information

Find the passages in the text where the following ideas are expressed . Give the line references.


___1 The processor is the control unit and arithmetic-logical unit.

___2 The processor operates on information that is in internal storage.

___3 The CPU directs all the activities of the computer.

___4 The control unit coordinates the sequencing of events within the processor.

___5 The word "computer" usually refers to the CPU plus internal memory.

___6 The CPU can get information from memory and put old or new information back into memory.

___7 The arithmetic-logical unit does the calculations and decision-making operations.


4 Contextual reference

Look back at the text and find out what the words in bold typeface refer to.


^ 1 for their particular computer .

2 it determines which operations

3 these two units are made up of

4 that can be in one of two states

5 that directs the sequence

6 in which the actual arithmetic operations

7 it also performs some kind of

8 unit and the arithmetic-logical unit operate

9 where manual control operations

10 it is used mainly when the computer


5 Understanding words

Refer back to the text and find synonyms (i.e. words with р similar meaning) for the following words.


1 specific

2 decides

3 job

4 movement

5 situated

6 get

Now refer back to the text and find antonyms (i.e. words with an opposite meaning) for the following words.

7 exceptional

8 generally

9 not needed

10 taken out

11 shut down


^ 6 WORD FORMS

First choose appropriate form of the words to complete the sentences. Then check the differences of meaning in your dictionary.


1 function, functional, functionally

a. Learning to program is a _____________ part of any course in computer science.

b.The central processing unit has many_____________ .

c.In order for the computer to _____________ properly, there should be no fluctuation in the electric current.


^ 2 sequence, sequential, sequentially

a. The control unit of the CPU directs the _____________ operations of the system.

b. Data must be presented ______________ to the processor unless the computer is programmed otherwise.

c. A program must be a detailed account of the _________________ the processor must follow to solve the problem.


^ 3 logic, logical, logically

a.To be a good programmer, one must be _________________ in ones approach to a problem.

b. The ________________ operations performed by the arithmetic-logical unit are under the control unit.

c. A program must be _________________ organized if successful results are to be obtained.

1   2   3




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