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How Does a Computer Operate?

Text: Numbers

 

I. Put the verbs into Present Perfect Progressive

1. Mr. Johnson (work) for this company for ten years.

2. Those two students (study) English for six months now.

3. The children (watch) TV since dinner time.

4. I’m getting tired. I (drive) this car since 8.00 a.m.

5. It (rain) heavily since two o’clock this afternoon.

6. She (talk) on the phone for fifteen minutes.

7. He (write) his book for five years.

8. They (do) their homework for two hours.

 

II. Complete the sentences with the verbs using Present Perfect Progressive

discuss, walk, do, work, paint, make, study, snow, wait

1. He _______ for two hours, tell him to rest a little.

2 "I _______ a long time for you," said my friend with a displeased air.

3. They_______ a noise since I came here.

4. I'm tired. We______ for six hours already.

5. Your face is dirty with paint. What you______? ____ you_______the house?

6. They_______ this problem for more than two hours.

7. There is a lot of snow in the street as it ___since yesterday.

8. How long _____ your brother_____ as a doctor?

 

III. Read the situations and complete the sentences.

1. The rain started two hours ago. It’s still raining now. It _________________ for two hours.

2. We started waiting for the bus 20 minutes ago. We’re still waiting now. We ______________________ for 20 minutes.

3. I started Spanish classes in December. I’m still learning Spanish now. I ________________________________________.

4. Ann began looking for a job six months ago. She’s still looking now.

Ann ______________________________

5. Mary started working in London on 18 January. She’s still working there. Mary ______________________________.

6. Years ago you started writing to a penfriend. You still write to each other regularly now. We ________________________________.

 

IV. Open the brackets and put the verbs into the proper tense, either the Present Progressive or the Present Perfect Progressive Tense.

1. Don't come in. He (take) an exam. He (take) his exam for half an hour already.

2. Where are the children? — They (play volleyball). They (play volleyball) since two o'clock,

3. 1 (learn) to type for a month and can say that my typing (improve).

4. Nick (come) round to see as tonight.

5. He (stay) at his sister's for six weeks. He (try) to find somewhere to live.

6. We can't dance as my father (work) in the study. He (prepare) a report. He (write) it for the whole day.

7. Do you see what the child (do) with your hat? Òakå it from him.

8. They still (discuss) the article? But they (do) it since twelve o'clock!

9. The prices (go up). They (rise) since 1991,

10. What a strong wind (blow)! It (blow) since yesterday.

 

V. Write two sentences for each situation. Use Present Perfect or Present Perfect Progressive.

VI. Put the verbs into Present Simple, Present Continuous, Present Perfect, Present Perfect Continuous.

1. He (to run) now. He (to run) for ten minutes without any rest.



2. What they (to do) now? — They (to work) in the reading-room. They (to work) there for already three hours.

3. Where he (to be) now? — He (to be) in the garden. He (to play) vol­ley-ball with his friends. They (to play) since break­fast time.

4. I (to live) in St. Petersburg. I (to live) in St. Petersburg since 1990.

5. She already (to do) her homework for two hours; but she (not do) half of it yet.

6. I (to wait) for you since two o'clock.

7. What you (to do)? — I (to read). I (to read) for already two hours. I already (to read) sixty pages.

8. This man (to be) a writer. He (to write) books. He (to write) books since he was a young man. He al­ready (to write) eight books.

9. What you (to do) here since morning?

10. Lena is a very good girl. She always (to help) her mother about the house. Today she (to help) her mother since morning. They already (to wash) the floor and (to dust) the furni­ture. Now they (to cook) dinner together.

 

VII. Read the text and say what kinds of numbers are mentioned.

 

 

Numbers

 

A number is a mathematical object used to count and measure. A symbol that represents a number is called a numeral. In addition to their use in counting and measuring, numerals are often used for labels (telephone numbers), for ordering (serial numbers), and for codes (e.g., ISBNs). In mathematics, the definition of number has been extended over the years to include such numbers as zero, negative numbers, rational numbers, irrational numbers, and complex numbers.

Certain procedures that take one or more numbers as input and produce a number as output are called numerical operations. Unary operations take a single input number and produce a single output number. More common are binary operations, which take two input numbers and produce a single output number. Examples of binary operations include addition, subtraction, multiplication, division, and exponentiation. The study of numerical operations is called arithmetic.

A negative number is any real number that is less than zero. Such numbers are often used to represent the amount of absence. For example, a decrease in some quantity may be thought of as a negative increase. Negative numbers are also used to describe values on a scale that goes below zero, such as the Celsius and Fahrenheit scales for temperature.

Negative numbers are usually written with a minus sign in front. For example, −3 would represent a negative quantity with a magnitude of three, and would be pronounced “minus three”. À number that is greater than zero is called positive; zero is usually thought of as neither positive nor negative.

In mathematics, every real number other than zero is either positive or negative. The positive whole numbers are referred to as natural numbers, while the positive and negative whole numbers (together with zero) are referred to as integers.

Negative numbers appeared for the first time in history in the Nine Chapters on the Mathematical Art (the period of the Chinese Han Dynasty (202 BC. – AD 220).

 

VIII. Mark the sentences as true or false.

· Every real number can be both positive and negative.

· A negative number is any real number that is less than zero.

· There are only binary operations in mathematics.

· The study of numerical operations is called geometry.

· Negative numbers appeared for the first time in history in the eleventh century.

· Exponentiation is a unary operation.

· Addition and multiplication are binary operations, but subtraction is a unary operation.

· The positive and negative whole numbers are called natural numbers.

 

IX. Prepare two questions for the text and ask your groupmates.

 

X. If you were to do a mind map of the text, what scheme would you make?

 

XI. Choose one of the topics and prepare a dialogue.

· You and your friend are thinking of a trip during your holidays. Discuss your plans.

· You spend all your time surfing the Internet. Your friend thinks that is really bad to spend all day long in front of the computer. Discuss the advantages and disadvantages of the Internet in everyday life.

How Does a Computer Operate?

 

Text A. Data Storage Device

A data storage device is a device for recording (storing) information (data).

Recording can be done using virtually any form of energy, spanning from

manual muscle power in handwriting, to acoustic vibrations in phonographic

recording, to electromagnetic energy modulating magnetic tape and optical

discs.

A storage device may hold information, process information, or both. A

device that only holds information is a recording medium. Devices that process

information (data storage equipment) may either access a separate portable (removable) recording medium or a permanent component to store and retrieve information.

Electronic data storage is storage which requires electrical power to store

and retrieve that data. Most storage devices that do not require vision and a

brain to read data fall into this category. Electromagnetic data may be stored in

either an analog or digital format on a variety of media. This type of data is

considered to be electronically encoded data, whether or not it is electronically

stored in a semiconductor device, for it is certain that a semiconductor device

was used to record it on its medium. Most electronically processed data storage

media (including some forms of computer data storage) are considered permanent

(non-volatile) storage, that is, the data will remain stored when power is

removed from the device. In contrast, most electronically stored information

within most types of semiconductor (computer chips) microcircuits are volatile

memory, for it vanishes if power is removed.

With the exception of barcodes and OCR data, electronic data storage is

easier to revise and may be more cost effective than alternative methods due to

smaller physical space requirements and the ease of replacing (rewriting) data

on the same medium. However, the durability of methods such as printed data

is still superior to that of most electronic storage media. The durability limitations

may be overcome with the ease of duplicating (backing-up) electronic data.

Many data storage devices are also media players. Any device that can

store and playback multimedia may also be considered a media player such as

in the case with the HDD media player.

Any input/output equipment may be considered data storage equipment if

it writes to and reads from a data storage medium. Data storage equipment uses

either:

 portable methods (easily replaced),

 semi-portable methods requiring mechanical disassembly tools

and/or opening a chassis, or

 inseparable methods meaning loss of memory if disconnected from

the unit.

A recording medium is a physical material that holds data expressed in

any of the existing recording formats. With electronic media, the data and the

recording medium is sometimes referred to as "software" despite the more

common use of the word to describe computer software.

 

Exercise 1. Match each of the words in the first column with the word from the second column to make five word partnerships from the article:

a. storage medium

b. recording device

c. digital device

d. volatile format

e. semiconductor memory

Exercise 2. Answer the questions:

1) What consumer electronic device uses a portable medium (tape reel)

to store the data?

2) What is a recording medium?

3) What type of data storage requires electrical power to store and retrieve

data?

4) In what format can electromagnetic data be stored?

5) What data storage media are considered permanent storage?

6) Why can electronic data storage be more cost effective than alternative

methods?

7) Can media players be called data storage devices?

8) What methods of recording are used by data storage equipment?

9) What is a recording medium?

Exercise 3. Expand the statements:

1) Recording can be done using virtually any form of energy, spanning

from manual muscle power in handwriting to acoustic vibrations in

phonographic recording.

2) A storage device may hold information.

3) Any device that can store and playback multimedia may also be considered

a media player.

4) Any input/output equipment may be considered data storage equipment.

5) A recording medium is a physical material.

6) With electronic media, the data and the recording medium is sometimes

referred to as "software".

7) With (traditional art) static media, art materials such as crayons may

be considered both equipment and medium.

8) Volatile organic compounds may be used to preserve the environment.

 

Text B. Computer Data Storage

A computer's memory can be viewed as a list of cells into which numbers

can be placed or read. Each cell has a numbered "address" and can store a single

number. The computer can 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 can be placed into memory with equal ease. Since the CPU

does not differentiate between different types of information, it is the software's

responsibility 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 (2^8 = 256); either from 0 to 255 or -128 to

+127. 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 can store any kind of information in memory if it can be represented

numerically. 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 to 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. As 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 contents

of RAM are erased when the power to the computer is turned off, but

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 required software may be stored in ROM. Software stored in ROM is often

called firmware, because it is notionally more like hardware than software.

Flash memory blurs the distinction between ROM and RAM, as it retains its data

when turned off but is also rewritable. It is typically much slower than conventional ROM and RAM however, so its use is restricted to applications where high speed is unnecessary.

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.

 

Exercise 4. What do the following abbreviations stand for? They are all used in the article:

PC CPU ALU RAM ROM BIOS

Exercise 5. Find the words in the article which mean the following. The first and the last letters are given:

1) describes events, numbers, etc. that follow one after another without

an interruption (paragraph 2) c…e

2) to remove something (paragraph 4) e … e

3) to arrange something carefully (paragraph 4) o … e

4) a set of instructions which form part of an electronic device and

which allow it to communicate with a computer or with other electronic

devices (paragraph 4) f … e

5) to intentionally become involved in a difficult situation in order to improve

it or prevent it from getting worse (paragraph 5) i … n

Exercise 6. Answer the following questions:

1) How can computer data storage be defined?

2) How does computer memory work (operate)?

3) What can significantly increase the computer’s speed?

4) What is the difference between RAM and ROM?

5) When is flash memory used?

 

 


Date: 2015-01-02; view: 1048


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