Вводный курс
Текст 1
The digital age
We are now living in what some people call the digital agе, meaning that computers have become an essential part of our lives. Young people who have grown up with PCs and mobile phones are 5 often called the digital generation. Computers help students to perform mathematical operations and improve their maths skills. They are used to access the Internet, to do basic research and to communicate with other students around the world. Teachers use projectors and interactive whiteboards to give presentations and teach sciences, history or language courses. PCs are also used for administrative purposes - schools use word processors to write letters, and databases to keep records of students and teachers. A school website allows teachers to publish exercises for students to complete online.Students can also enrol for courses via the website and parents can download official reports.
Mobiles let you make voice calls, send texts, email people and download logos, ringtones or games. With a built-in camera you can send pictures and make video calls in face-to-face mode. New smartphones combine a telephone with web access, video, a games console, an MP3 player, a personal 25 digital assistant (PDA) and a GPS navigation system, all in one.
In banks, computers store information about the money held by each customer and enable staff to access large databases and to carry out financial transactions at high speed.They also control the cashpoints, or ATMs (automatic teller machines), which dispense money to customers by the use of a PIN-protected card. People use a Chip and PIN card to pay for goods and services. Instead of using a 35 signature to verify payments, customers are asked to enter a four-digit personal identification number (PIN), the same number used at cashpoints; this system makes transactions more secure. With online banking, clients can easily pay bills and transfer 40 money from the comfort of their homes.
Airline pilots use computers to help them control the plane. For example, monitors display data about fuel consumption and weather conditions. In airport control towers, computers are used to 45 manage radar systems and regulate air traffic. On the ground, airlines are connected to travel agencies by computer. Travel agents use computers to find out about the availability of flights, prices, times, stopovers and many other details.
1. Определите, какой частью речи являются следующие слова (существительным, глаголом, прилагательным, наречием):
perform, word processor, online, download, built-in, digital, store, financial, monitor, data.
Подберите определение для каждого слова
a keep, save
b execute, do
с monetary
d screen
e integrated
f connected to the Internet
g collection of facts or figures
h describes information that is recorded or broadcast using computers
i program used for text manipulation
j copy files from a server to your PC or mobile
2. Переведите словосочетания на русский язык
perform operations, accsess the Internet, do research, make calls, send texts, display data, write letters, store information, complete exercises, carry out transactions.
3. Составьте словосочетания и перведите их на русский язык
| give | a | money | |
| keep | b | a PIN | |
| access | с | databases | |
| enter | d | presentations | |
| transfer | e | records |
4. Используя словосочетания из упражнений 2и 3, заполните пропуски в предложениях. Переведите полученные предложения на русский язык.
1 Thanks to Wi-Fi, it's now easy to............................................from cafes, hotels, parks and many other public places.
2 Online banking lets you..................................................................between your accounts easily and securely.
3 Skype is a technology that enables users to...............................................over the Internet for free.
4 In many universities, students are encouraged to...............................using PowerPoint in order to make their talks more visually attractive.
5 The Web has revolutionized the way people.........................................- with sites such as Google and Wikipedia, you can find the information you need in seconds.
6 Cookies allow a website to.................................................on a user's machine and later retrieve it; when you visit the website again, it remembers your preferences.
7 With the latest mobile phones, you can..................................................with multimedia attachments - pictures, audio, even video.
Текст 2.
What is a computer?
A computer is an electronic machine which can accept data in a certain form, process the data, and give the results of the processing in a specified format as information.
First, data is fed into the computer's memory. Then, when the program is run, the computer performs a set of instructions and processes the data. Finally, we can see the results (the output) on the screen or in printed form (see Fig. 1 below).
A computer system consists of two parts: hardware and software. Hardware is any electronic or mechanical part you can see or touch. Software is a set of instructions, called a program, which tells the computer what to do. There are three basic hardware sections: the central processing unit (CPU), main memory and peripherals
Perhaps the most influential component is the central processing unit. Its function is to execute program instructions and coordinate the activities of all the other units. In a way, it is the'brain'of the computer. The main memory (a collection of RAM chips) holds the instructions and data which are being processed by the CPU. Peripherals are the physical units attached to the computer. They include storage devices and input/ output devices.
Storage devices (hard drives, DVD drives or flash drives) provide a permanent storage of both data and programs Disk drives are used to read and write data on disks. Input devices enable data to go into the computer's memory. The most common input devices are the mouse and the keyboard. Output devices enable us to extract the finished product from the system. For example, the computer shows the output on the monitor or prints the results onto paper by means of a printer.
On the rear panel of the computer there are several ports into which we can plug a wide range of peripherals - a modem, a digital camera, a scanner, etc. They allow communication between the computer and the devices. Modern desktop PCs have USB ports and memory card readers on the front panel.
1. Найдите определение для каждого термина
| 1 software 2 peripherals 3 main memory 4 hard drive (also known as hard disk) computer system 5 hardware 6 input 7 ports 8 output 9 central processing unit (CPU) | a the brain of the computer b physical parts that make up a computer system с programs which can be used on a particular d the information which is presented to the computer e results produced by a computer f input devices attached to the CPU g section that holds programs and data while they are executed or pressed h magnetic device used to store information i sockets into which an external device may be connected |
2. Перед вами названия основных типов компьютеров. Найдите аналоги их названию в русском языке.
Laptop, desktop PC, PDA, mainframe, tablet PC
Являются ли следующие утверждения верными?
1 A mainframe computer is less powerful than a PC.
2 A mainframe is used by large organizations that need to process enormous amounts of data.
3 The most suitable computers for home use are desktop PCs.
4 A laptop is not portable.
5 Laptops are not as powerful as desktop PCs.
6 Using a stylus, you can write directly onto the screen of a tablet PC.
7 A Personal Digital Assistant is small enough to fit into the palm of your hand.
8 A PDA does not allow you to surf the Web.
3. Для проведения классификаций в английском языке используются следующие словосочетания:
•... are classified into X types/categories
•... are classified by...
•... can be divided into X types/categories
Digital computers can be divided into five main types: mainframes, desktop PCs, laptops, tablet PCs and handheld PDAs.
•... include(s)...
•... consist(s) of...
The basic configuration of a mainframe consists of a centra) system which processes immense amounts of data very quickly.
• There are X types/classes of...
• X is a type of...
A tablet PC is a type of notebook computer.
Используя данные выше словосочетания, заполните пропуски в предложениях. Предлоджения переведите на русский язык.
1 A computer............................................ hardware and software.
2 Peripherals................................. three types: input, output and storage devices.
3 A word processing program................................................software which lets
the user create and edit text.
4 ….........................................of network architectute: peer-to-peer, where all
computers have the same capabilities, and client-server (e.g. the Internet), where servers store and distribute data, and clients access this data.
Текст 3.
How screen displays work
Displays, often called monitors or screens, are the most-used output device on a computer. They provide instant feedback by showing you text and graphic images as you work or play.
Most desktop displays use Liquid Crystal Display (LCD) or Cathode Ray Tube (CRT) technology, while nearly all portable computing devices, such as laptops, incorporate LCDs. Because of their slimmer design and lower energy consumption, LCD monitors (also called flat panel or flat screen displays) are replacing CRTs.
Basic features
Resolution refers to the number of dots of colour, known as pixels (picture elements), contained in a display. It is expressed by identifying the number of pixels on the horizontal and vertical axes. A typical resolution is 1024x768.
A pixel is a combination of red, green and blue subpixels
Two measurements describe the size of your display: the aspect ratio and the screen size. Historically, computer displays, like most televisions, have had an aspect ratio of 4:3 - the width of the screen to the height is four to three. For widescreen LCD displays, the aspect ratio is 16:9, very useful for viewing DVD movies, playing games and displaying multiple windows side by side. High-definition TV also uses this format.The viewable screen size is measured diagonally, so a 19"screen measures 19" from the top left to the bottom right.
Inside the computer there is a video adapter, or graphics card, which processes images and sends signals to the monitor. CRT monitors use a VGA (video graphics adapter) cable, which converts digital signals into analogue signals. LCD monitors use a DVI (digital video interface) connection.
Colour depth refers to the number of colours a monitor can display. This depends on the number of bits used to describe the colour of a single pixel. For example, an old VGA monitor with an 8-bit depth can generate 256 colours and a SuperVGA with a 24-bit depth can generate 16.7 million colours. Monitors with a 32-bit depth are used in digital video, animation and video games to get certain effects.
Display technologies
An LCD is made of two glass plates with a liquid crystal material between them. The crystals block the light in different quantities to create the image. Active-matrix LCDs use TFT (thin film transistor) technology, in which each pixel has its own switch. The amount of light the LCD monitor produces is called brightness or luminance, measured in cd/m2(candela per square metre).
A CRT monitor is similar to a traditional TV set. It contains millions of tiny red, green and blue phosphor dots that glow when struck by an electron beam that travels across the screen and create a visible image.
PCs can be connected to video projectors, which project the image onto a large screen. They are used for presentations and home theatre applications.
In a plasma screen, images are created by a plasma discharge which contains noble (non-harmful) gases. Plasma TVs allow for larger screens and wide viewing angles, making them ideal for movies.
Organic Light-Emitting Diodes (OLEDs) are thin-film LED displays that don't require a backlight to function. The material emits light when stimulated by an electrical current, which is known as electroluminescence.They consume less energy, produce brighter colours and are flexible - i.e. they can be bent and rolled up when they're not being used.
1. Переведите следующие термины: resolution, pixel, aspect ratio, colour depth, video adapter, plasma screen
Найдите определение для каждого термина
1 the smallest unit on a display screen or bitmapped image (usually
a coloured dot)
2 an expansion card that generates the video signal sent to a
computer display
3 the width of the screen in proportion to its height
4 also called gas discharge display
5 the number of pixels contained in a display, horizontally and
vertically
6 the number of bits used to hold a colour pixel; this determines
the maximum number of colours that can be displayed
2. Ответьте на вопросы
1 What do CRT and LCD stand for?
2 How is the screen size measured?
3 What technology is used by active-matrix LCDs?
4 Which unit of frequency is used to measure the brightness of a display?
5 What substance produces light and colour when hit by electrons in a CRT monitor?6 What are the three advantages of OLED displays?
Текст 4
Databases
A database is a collection of related data, and the software used in databases to store, organize and retrieve the data is called the database management system,
or DBMS. However, we often use the word database to cover both meanings. A database can manage any type of data, including text, numbers, images, sound, video and hyperlinks (links to websites).
Information is entered into the database via fields. Each field holds a separate piece of information, and the fields are grouped together in records.Therefore, a record about an employee might consist of several fields which give their name, address, phone number, date of birth, salary and length of employment with the company.
Records are grouped together into files which hold large amounts of information. Files can easily be updated -you can always change fields, add new records or delete old ones. An electronic database is much faster to consult and update than a card index system and occupies a lot less space. With the right software, you can keep track of stock, sales, market trends, orders and other information that can help your company stay successful.
A database program lets you create an index - a list of records ordered according to the content of certain fields. This helps you to search the database and sort
records into numerical or alphabetical order very quickly. Modern databases are relational - that is, they are made up of related files: customers and orders, vendors and purchases, students and tutors, etc.Two database files can be related as long as they have a common field. A file of students, for example, could include a field called Tutor ID and another file with details of the tutors could include the same field. This key field can be used to relate the two files. Databases like Oracle, DB2 and MySQL can manage these relationships.
A database query function allows you to extract information according to certain conditions or criteria. For example, if a managing director wanted to know all the customers that spend more than?8,000 per month, the program would search on the name field and the money field simultaneously.
The best database packages also include network facilities, which can make businesses more productive. For example, managers of different departments can have direct access to a common database. Most aspects of the program can be protected by user-defined passwords and other security devices. For example, if you wanted to share an employee's personal details but not their commission, you could protect the commission field.
Текст 5
Computer languages
Unfortunately for us, computers can't understand spoken English or any other natural language. The only language they can understand directly is machine code, which consists of 1 s and Os (binary code).
Machine code is too difficult to write. For this reason, we use symbolic languages to communicate instructions to the computer. For example, assembly languages use abbreviations such as ADD, SUB, MPY to represent instructions. The program is then translated into machine code by a piece of software called an assembler. Machine code and assembly languages are called low-level languages because they are closer to the hardware.They are quite complex and restricted to particular machines. To make the programs easier to write, and to overcome the problem of intercommunication between different types of computer, software developers designed high-level languages, which are closer to the English language. Here are some examples:
■ FORTRAN was developed by IBM in 1954 and is still
used for scientific and engineering applications.
■ COBOL (Common Business Oriented Language) was developed in 1959 and is mainly used for business applications.
■ BASIC was developed in the 1960s and was widely used in microcomputer programming because it was easy to learn. Visual BASIC is a modern version of the old BASIC language, used to build graphical elements such as buttons and windows in Windows programs.
■ PASCAL was created in 1971. It is used in universities to teach the fundamentals of programming.
С was developed in the 1980s at AT&T. It is used to write system software, graphics and commercial applications. С++ is a version of С which incorporates object-oriented programming: the programmer concentrates on particular things (a piece of text, a graphic or a table, etc.) and gives each object functions which can be altered without changing the entire program. For example, to add a new graphics format, the programmer needs to rework just the graphics object. This makes programs easier to modify.
■ Java was designed by Sun in 1995 to run on the Web
Java applets provide animation and interactive features on web pages.
Programs written in high-level languages must be translated into machine code by a compiler or an interpreter. A compiler translates the source code into object code - that is, it converts the entire program into machine code in one go. On the other hand, an interpreter translates the source code line by line as the program is running.
It is important not to confuse programming languages with markup languages, used to create web documents. Markup languages use instructions, known as markup tags, to format and link text files. Some examples include:
■ HTML, which allows us to describe how information will be displayed on web pages.
■ XML, which stands for Extensible Markup Language. While HTML uses pre-defined tags, XML enables us to define our own tags; it is not limited by a fixed set of tags.
■ VoiceXML, which makes Web content accessible via voice and phone. VoiceXML is used to create voice applications that run on the phone, whereas HTML is used to create visual applications (for example, web pages).
<xml>
< name> Andrea Finch </name>
< homework> Write a paragraph describing the С language </homework>
</xml>
In this XML example we have created two new tags: <name> and <homework>
Текст 6
Email Protocols
Although the format of a mail message, as transmitted from one machine to another, is rigidly defined, different mail protocols transfer and store messages in slightly different ways.The mail system you're probably used to employs a combination of SMTP and P0P3 to send and receive mail respectively. Others may use IMAP4 to retrieve mail, especially where bandwidth is limited or expensive.
Simple Mail Transfer Protocol
SMTP is used to transfer messages between one mail server and another. It's also used bv email programs on PCs to send mail to the server. SMTP is very straightforward, providing only facilities to deliver messages to one or more recipients in batch mode. Once a message has been delivered, it can't be recalled or cancelled. It's also deleted from the sending server once it's been delivered. SMTP uses 'push' operation, meaning that the connection is initiated by the sending server rather than the receiver. This makes it unsuitable for delivering messages to desktop PCs, which aren't guaranteed to be switched on at all times. In host-based mail systems, such as Unix and Web mail, SMTP is the only protocol the server uses.
Received messages are stored locally and retrieved.
In case of Web mail, the message is then translated into HTML and transmitted to your browser. SMTP is the only protocol for transferring messages between servers. How they're then stored varies from system to system.
Post Office Protocol
POP is a message-retrieval protocol used by many PC mail clients to get messages from a server, typically your ISP's mail server. It only allows you to download all messages in your mailbox at once. It works in 'pull' mode, the receiving PC initiating the connection. PC-based POP3 mail clients can do this automatically at a preset interval. When you use your Web mail account to access a POP3 mailbox, the mail server opens a connection to the P0P3 server just as a PC-based application would. The messages are then copied into your Web mailbox and read via a browser.
Since POP3 downloads all the messages in your mailbox, there's an option to leave messages on the server, so that they can be picked up from different machines without losing any. This does so mean that you'll get every message downloaded every time you connect to the server. If you don't clean out your mailbox regularly, this could mean long downloads. When using a Web mail account torttrlevt POP3 mail, be careful about leaving 55 messages on the server - if too many build up, each download will take a long time and fill up your inbox. Many Web mail systems won't recognise messages you've already downloaded, so you'll get duplicates of ones you haven't deleted.
Internet Mail Access Protocol
MAP is similar in operation to POP, but allows you more choice over what messages you download. Initially, only message headers are retrieved, giving information about the sender and subject. You can then download just those messages you want to read. You can also delete individual messages from the server, and some MAP servers let you organise your mail into folders. This makes download times shorter and there's no danger of losing messages.
Текст 7
THE ANATOMY OF A VIRUS
A biological virus is a very small, simple organism that infects living cells, known as the host, by attaching itself to them and using them to reproduce itself. This often causes harm to the host cells.
Similarly, a computer virus is a very small program routine that infects a computer system and uses its resources to reproduce itself. It often does this by patching the operating system to enable it to detect program files, such as COM or EXE files. It then copies itself into those files. This sometimes causes harm to the host computer system.
When the user runs an infected program, it is loaded into memory carrying the virus. The virus uses a common programming technique to stay resident in memory. It can then use a reproduction routine to infect other programs. This process continues until the computer is switched off.
The virus may also contain a payload that remains dormant until a trigger event activates it, such as the user pressing a particular key. The payload can have a variety of forms. It might do something relatively harmless such as displaying a message on the monitor
screen or it might do something more destructive such as deleting files on the hard disk.
When it infects a file, the virus replaces the first instruction in the host program with a command that changes the normal execution sequence. This type of command is known as a JUMP command and causes the virus instructions to be executed before the host program. The virus then returns control to the host program which then continues with its normal sequence of instructions and is executed in the normal way.
To be a virus, a program only needs to have a reproduction routine that enables it to infect other programs. Viruses can, however, have four main parts. A misdirection routine that enables it to hide itself; a reproduction routine that allows it to copy itself to other programs; a trigger that causes the payload to be activated at a particular time or when a particular event takes place; and a payload that may be a fairly harmless joke or may be very destructive. A program that has a payload but does not have a reproduction routine is known as a Trojan.
Текст 8
Safe Data Transfer
Secure transactions across the Internet have three goals. First, the two parties engaging ma transaction (say, an email or a business purchase) don't want a third party to be able to read their transmission. Some form of data encryption is necessary to prevent this. Second, the receiver of the message should be able to detect whether someone has tampered with it in transit. This calls for a message-integrity scheme. Finally, both parties must know that they're communicating with each other, not an impostor. This is done with user authentication.
Today's data encryption methods rely on a technique called public-key cryptography. Everyone using a public-key system has a public key and a private key. Messages are encrypted and decrypted with these keys. A message encrypted with your public key can only be decrypted by a system that knows your private key.
For the system to work, two parties engaging in a secure transaction must know each other's public keys. Private keys, however, are closely guarded secrets known only to their owners. When I want to send you an encrypted message fuse your public key to turn my message into gibberish. I know that only you can turn the gibberish back into the original message, because only you know your private key. Public- key cryptography also works in reverse - that is only your public key can decipher your private key's encryption.
To make a message tamper-proof (providing message integrity), the sender runs each message through a message-digest function. Thi function within an application produces a number called a message-authentication code (MAC). The system works because it's almost impossible for an altered message to have the same MAC as another message. Also, you can't take a MAC and turn it back into the original message.
The software being used for a given exchange produces a MAC for a message before it's encrypted. Next, it encrypts the MAC with the sender's private key. It then encrypts both the message and the encrypted MAC with the recipient's public key and sends the message.
When the recipient gets the message and so decrypts it, they also get an encrypted MAC. The software takes the message and runs it through the same message-digest function that the sender used and creates its own MAC. Then it decrypts the sender's MAC. If the two are the same, then the message hasn't been tampered with.
The dynamics of the Web dictate that a user-authentication system must exist. This can be done using digital certificates.
A server authenticates itself to a client by sending an unencrypted ASCII-based digital, certificate. A digital certificate contains information about the company operating the server, including the server's public key. The digital certificate is 'signed' by a trusted digital-certificate issuer, which means that the issuer has investigated the company operating the server and believes it to be legitimate. If the client trusts the issuer, then it can trust the server. The issuer 'signs' the certificate by generating a MAC for it, then encrypts the MAC with the issuer's private key. If the client trusts the issuer, then it already knows the issuer's public key.
The dynamics and standards of secure transactions will change, but the three basic tenets of secure transactions will remain the same. If you understand the basics, then you're already three steps ahead of everyone else.
Текст 9