Computer Hardware and Functionality of the Computer
What is a computer? A computer is an electronic machine that processes information - in other words, an information processor. It takes in raw information (or data) at one end (input), processes it, stores it until it is necessary (memory) and then spits out the results at the other end (output). Your keyboard and mouse, for example, are input units - ways of getting information into your computer that it can process, if you use a microphone and voice recognition software, that's another form of input. Your computer stores all your documents and files on a hard-drive: a huge magnetic memory. But smaller, computer-based devices like digital cameras and cell-phones use other kinds of storage such as flash memory cards. As for output, your computer has a screen and stereo loudspeakers. You may have an ink-jet or laser printer too to make an output. Your computer's processor (CPU) is a microchip buried deep inside. It works amazingly hard and gets incredibly hot in the process. That's why your computer has a little fan blowing away - to stop its brain from overheating!
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. Peripherals are the physical units attached to the computer. They include storage devices and input/output devices.
Computer case. The computer case contains the most important components of the computer: the motherboard, the processor, random access memory modules, the hard drive etc.
· Motherboard. The motherboard is the part of the computer where such things as the processor, memory modules, expansion cards and external devices are attached. This means that the motherboard controls the functions of different components.
· Processor. The processor can be considered to be the 'engine' of the computer because it executes the lion's share of the information processing; the processor fetches commands and necessary information from the RAM, carries out the tasks specified by the commands, and returns the processed information to the RAM. The speed of a computer depends largely on the speed of the processor.
· Random Access Memory. The RAM is a memory storage that functions during computer use and is especially utilized by the processor. In modern computers, the amount of RAM is around 4-16 GB depending on the type and purpose of the computer. The RAM consists of one or more memory modules. When the computer is started, the operating system is loaded into the RAM (an operating system is a program that controls the devices and programs in a computer). The computer also loads the files being processed - music, assignments, videos etc - to the RAM. If there is enough RAM, the computer executes requested tasks quickly. This is why it is a good idea to add to the memory by buying more memory modules as the need arises.
· Hard drive. The hard drive is the permanent memory of the computer where saved files remain even when the computer is turned off. This is why the hard drive is used for saving files. The capacity of hard drives varies; currently the typical capacity is 500 - 1000 GB, but hard drives of over 1500 GB, i.e. 1,5 terabit, are also available. However, the capacity of the internal hard drives in laptop computers is often less than that.
· Display and display adapter. Most computer displays are so-called LCD displays (Liquid Crystal Display), where the image display is produced by liquid crystals between two transparent sheets. Display sizes range between only a few inches in handheld apparatuses to large 24 inch desktop displays. One of the most important features of the display is its resolution, i.e. how many pixels (picture elements) the image consists of.
Keyboard. A standard keyboard has 102 keys. The keys are divided into alphabetical (a-z), numerical (1-0) and special (Function, Ctrl, Alt etc keys). Special keys are located among the alphabetical ones.
· Ctrl (Control) is used in combination with other keys for different
actions. The combinationCtrl+C, for example, copies the chosen data to the memory;
· Alt (Alternative) is used like the Ctrl key. Sometimes both these keys are used in combination: Ctrl+Alt+Del, for example, brings up the task manager (in Windows XP);
· Alt Gr (Alternative Graphics) produces the 'third character' of the keys, e.g. @, $, £ and }.With this key, you can also create the ~ character (important for the Internet);
· Shift: capitalizes letters and the special characters on the numerical keys, among
· Caps Lock locks the capitalization of letters. This function is connected with an A or Caps lock pilot light on the keyboard. It turns on the light when the function is in use;
· Tab: the tabulator is mainly used in word processing: each time you press the tab button, the cursor moves to the next tab stop on the same row;
· Backspace: removes the characters to the left of the cursor, i.e. what you just wrote. This key can also be used to remove a larger portion of text;
· Enter by pressing this key you can change paragraphs or e.g. accept a function.
The keyboard also has the rarely used keys Print Screen, Scroll Lock and Pause.
Pointing devices. Traditionally, most programs have been designed to be used with a mouse. The mouse cursor seen on the screen of the computer moves along with the mouse. The cursor can be used to select menu commands and areas, as well as activating different objects by clicking the mouse keys.
· Mouse. You can attach a traditional mouse with or without a cord to any computer. Cordless mice use radio waves to relay movement from the mouse to the computer (for this mouse, a small radio receiver is attached to the computer).
· Touchpad. Almost all laptop computers have a touchpad which is used to move the cursor. Some models also have a so-called pointing stick. In addition, portable computers have keys with the clicking function of a mouse. The touchpad is a pad where you can control the cursor by moving your finger along the pad. Tapping the pad serves the same function as clicking a mouse.
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 USS ports and memory card readers on the front panel.
Ex. 1. Answer the questions:
1. What is a computer? 2. How can a computer be characterized from the point of view of its constituent parts? Give brief characteristics of each one. 3. Why is a computer said to simulate a calculator? How do they differ?
Ex. 2. Match these words from the text (1-9) with the correct meanings (a-i).
Ex. 3. Look at the list of the following terms and put each one in an appropriate column of the table. The first one has been done for you.
Ex. 4. Listen and complete the extract from the conversation.
Assistant: Do you need any (1) ...
Paul: Um, yes, we're looking for a Mac computer. Have you got any fairly basic ones?
Assistant: Yes, sure. If you'd like to come over here.
Paul: What different (2) ... are there?
Assistant: At the moment we've got these two models: the iMac, which is a desktop computer with an Intel Core 2 Duo processor (3) ... at 2.33 gigahertz, and the portable MacBook, which has a processor (4) ... at 2.0 gigahertz. Core Duo technology actually means two cores, or processors, built into a single chip, offering up to twice the speed of a traditional chip.
Sue: So they're both very (5) ... which has more RAM? ... ,then. And which one has more memory, I mean.
Assistant: Well, the iMac has two gigabytes of RAM, which can be (6) ... up to three gigabytes, and the MacBook has one gigabyte, expandable to two gigabytes. It all depends on your needs. The iMac is (7) ... for home users and small offices. The MacBook is more (8) ... if you travel a lot.
Ex. 5. Work in pairs. One of you wants to buy a computer, the other is the shop assistant. Use the prompts and product descriptions below to role play the conversation.
Ex. 6. Input devices are the pieces of hardware which allow us to enter information into the computer (keyboard, digital camera, mouse, joystick, webcam, microphone, scanner, graphics tablet, touch screen, lightpen, barcode reader, touchpad, trackball). Which input device would you use for these tasks?
1) to play computer games;
2) to copy images from paper into a computer;
3) to read price labels in a shop;
4) to select text and click on links on web pages;
5) to enter drawings and sketches into a computer;
6) to input voice commands and dictate text;
7) to draw pictures or select menu options directly on the screen;
8) to take and store pictures and then download them to a computer.
Ex. 7. Complete each sentence by choosing from the following devices: touch screen, trackball, touchpad, webcam.
1. A ... is a stationary device that works like a mouse turned upside down. You roll the ball with your hand to move the pointer on the screen. 2. Interactive ... are used in museums, information centres and Internet kiosks. You use your finger to point directly to objects on the screen. 3. A ... is used to send live video images via the Internet. 4. A ... is found on notebook PCs. You use it by pressing the sensitive pad with a finger.
Ex. 8. Read the passage and complete these sentences with the correct 'mouse action'.
A mouse is a hand-held device that lets you move a pointer (or cursor) and select items on the screen. It has one or more buttons to communicate with the PC. A scroll wheel lets you move through your documents or web pages. The pointer looks like an I-bar, an arrow or a pointing hand. An optical mouse has an optical sensor instead of a ball underneath. A cordless (wireless) mouse has no cable; it sends data via infrared signals or radio waves.
- to click, press and release the left button;
- to double-dick, press and release the left button twice;
- to drag, hold down the button, move the pointer to a new place and then release the button;
- to right-click, press and release the right button; this action displays a list of commands.
1. To start a program or open a document you ... on its icon - that is, you rapidly press and release the mouse button twice. 2. If you want to select a menu option, you just ...on the left button. 3. If you want to find the commands for a particular text, image, etc., you have to ... on it. 4. If you want to move an object, press the button and ...the object to the desired location.
Ex. 9. Read the passage and complete these sentences with words written in bold type.
A printer is a device that prints your texts or graphics on paper. The output on paper or acetate sheets is called printoutor hard copy. A program in your computer, called the printer driver, converts data into a form that your printer can understand. A print spooler stores files to be printed when the printer is ready. It lets you change the order of documents in the queue and cancel specific print jobs. The output quality, or resolution, is measured in dpi or dots per inch. The speed of your printer is measured in pages per minute (ppm). In a network, users can share a printer connected to a print server, a computer that stores the files waiting to be printed.
1. The differences in ... are noticeable: the more dots per inch, the clearer the image. 2. A print resolution of between 600 .... and 2,400 ... ensured that even text as small as 2 pt was legible. 3. Passengers with an electronic ticket will need a ... of ticket confirmation or a boarding pass to be admitted to secured gate areas. 4. The key advance of recent years is printing speed: the latest generation of ink-jets prints black-and-white text at 15 ... ... ... (...). 5. With appropriate software, you can view the images on a computer, manipulate them, or send them to a ... and produce excellent quality colour copies. 6. A ... ... is a dedicated computer that connects a printer to a network. It enables users to share printing resources. 7. A ... ... is a utility that organizes and arranges any documents waiting to be printed. 8. In computers, a .... ... is a program installed to control a particular type of printer.
Ex. 10. Read the passage and complete the sentences with the comparative or superlative form of the adjectives in brackets.
A dot-matrix printer uses a group, or matrix, of pins to create precise dots. A print head containing tiny pins strikes an inked ribbon to make letters and graphics. This impact printing technology allows shops, for example, to print multi-part forms such as receipts and invoices, so it's useful when self-copying paper is needed. It has two important disadvantages: noise and a relatively low resolution (from 72 to 180 dpi).
An ink-jet (also called bubble-jet) printer generates an image by spraying tiny, precise drops of ink onto the paper. The resolution ranges from 300 to 1,200 dpi, suitable for small quantities or home use. A standard ink-jet has a three-colour cartridge, plus a black cartridge. Professional ink-jets have five-colour cartridges, plus black; some can print in wide format, ranging from 60 cm up to 5 metres (e.g. for printing advertising graphics). Some ink-jet based printers can perform more than one task. They are called multi-function printers because they can work as a scanner, a fax and a photocopier as well as a printer. Some units accept memory cards and print photos directly from a camera.
A laser printer uses a laser beam to fix the ink to the paper. A laser works like a photocopier; a powder called toner is attracted to paper by an electrostatic charge and then fused on by a hot roller. Laser printers are fast and produce a high resolution of 1,200 to 2,400 dpi, so they are ideal for businesses and for proofing professional graphics work.
A professional image-setter is a typesetting printer that generates very high-resolution output (over 3,540 dpi) on paper or microfilm. It's used for high-quality publications.
A plotter is a special type of printer which uses ink and fine pens held in a carriage to draw detailed designs on paper. It's used in computer-aided design, maps, 3-D technical illustrations, etc.
1. Dot-matrix printers are ... (chip) than laser printers. 2. Professional image-setters have ... (high) resolution that's why they are used for high-quality publications. 3. Ink-jet printers are ... (slow) than laser printers. 4. Laser printers are ... (expensive) than ink-jet printers. 5. My printer is ... (bad) in the world. It never works when I need it.
Ex. 12. Read the passage and answer the following question: which device or format would be most suitable for storing these things?
1. The operating system and the programs on a home computer. 2. An electronic encyclopedia for children. 3. A movie in digital format. 4. The music tracks by your favorite artist Panasonic portable DVD player. 5. All the files generated by a company in one day. 6. The photos taken with a digital camera.
Magnetic storage. Magnetic devices store data magnetically. A disk drive spins the disk at high speed and reads its data or writes new data onto it.
- A floppy disk drive uses 3.5 inch diskettes which can only hold 1.44 MB of data; it's often called A: drive and is relatively slow. It is not used today. It is an out-of-date (outdated) device.
- Most PCs have one internal hard disk, usually called C: drive, which can hold several gigabytes of data. It's used to keep the operating system, the programs and the user's files easily available for use. When you format a disk, or prepare it for use, its surface is divided into concentric circles called tracks. Each track is further divided into a number of sectors. The computer remembers where information is stored by noting the track and sector numbers in a directory. The average time required for the read/write heads to move and find data is called access time; it is measured in milliseconds (ms). Don't confuse 'access time' with 'transfer rate', the rate of transmission of data from the disk to the CPU (e.g. 15 megabytes per second).
A portable hard drive is an external unit with the drive mechanism and the media all in one scaled case. You can use it to make a backup, a spare copy of your files, or to transport data between computers.
Optical storage. Optical drives use a laser to read and write data, so they are not affected by magnetic fields; but they are slower than hard drives. Modern DVD recorders accept all CD and DVD formats.
CDs (compact discs) can store up to 650-700 MB of data.
- CD-ROMs (read only memory) are 'read-only' units, so you cannot change data stored on them (e.g. a dictionary or a game).
- CD-R (recordable) discs are write-once devices which let you duplicate CDs.
- CD-RW (rewritable) discs enable you to write onto them in multiple sessions, like a hard disk.
DVDs (digital versatile discs) are similar in size to CDs (both are 1.2 mm thick), but they differ in structure and capacity. DVDs have more tracks and more pits (tiny holes) per track, and can store from 4.7 GB to 17 GB of data, movies, high-definition sound, etc. so they will probably replace CDs.
DVD formats include:
- DVD-ROM (read-only memory)
- DVD-R or DVD+R (recordable only once)
- DVD-RW or DVD+RW (rewritable, so it can be erased and reused many times). Portable DVD players let you watch movies or TV, play games and listen to music, wherever you are. They usually run on batteries, have a widescreen (rectangular 16:9 format) LCD and support multi-format playback, allowing you access to many file formats including DVD video, JPEG pictures, MP3 music, etc. They have two built-in stereo speakers, or headphones if you don't want to disturb other people.
Removable flash memory. Flash memory is solid-state, rewritable memory; it is non-volatile, so it retains data when the power is turned off. This explains its popularity in small devices. Flash memory cards such as CompactFlash or Secure Digital are found in cameras, PDAs and music players. Flash drives, also known as thumb or pen drives, are connected to a USB port of the computer. They let you save and transfer data easily.
Ex. 13. Summarize the text using the following words:
raw information, input/output, storage, printers, a computer case, a keyboard, pointing devices, hardware/software, peripherals, magnetic storage, optical storage.
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