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Chapter 1: Hardware 1 Chapter 1: Hardware 1 Chapter 1: Hardware Chapter 1: Hard

Chapter 1: Hardware 1 Chapter 1: Hardware 1 Chapter 1: Hardware Chapter 1: Hardware You need to know: • A computer follows a set of instructions (a program) to input, process, store and output data and information. • Hardware is equipment, e.g. a PC and its component parts, e.g. a keyboard, monitor and mouse. • Computers are desktop PCs, laptops, tablets, hand-held computers, games consoles, embedded computers, mainframe computers or supercomputers. • Input devices include the keyboard and pointing devices, e.g. a mouse or trackpad. • Output devices include monitors, printers and speakers. What is a computer? A computer is an electronic machine that inputs data, processes it under the control of a stored program, and outputs information. While the data is being processed, data can be retrieved from or saved on backing storage. Data is raw, unprocessed information. Information is data that people understand. In order to understand data, you may have to interpret it: The number 30112012 is data that can be interpreted as: • A date 30/11/2012 • A sum of money $301,120.12 The interpreted data, that is the date or the sum of money, is the information. Data input Program instructions and data Data is retrieved or saved Process Data output • Input – data is entered into the computer. • Process – a computer is controlled by a program, that is, a sequence of instructions. It processes the input data automatically following these instructions. • Store – the program and data are stored, e.g. on a hard disk, for later retrieval. • Output – the computer communicates to the user, e.g. it displays graphics on the screen. Figure 1.1 Flow of data Page 1 of 40 2 Chapter 1: Hardware Types of computer Computers can be: • PCs (personal computers) – a microcomputer for individual use. • Mainframe computers – large computer, with huge processing power. • Minicomputers – smaller version of a mainframe. • Supercomputers – very large mainframe. Different types of PC • Desktop – has these basic components: monitor, keyboard, system unit and mouse. • Laptop – a portable computer slightly larger than A4 size. • Tablet (or pad) – a very small portable computer with a touch-sensitive screen and no keyboard. • Notebook – a small laptop computer. • Netbook – very small laptop optimised for Internet and email access. • Hand-held computer, e.g. smart phone – fits into one hand and has a touch-sensitive screen. Can be temporarily attached to a keyboard. • Games console – a PC designed for playing games, e.g. Xbox. Has these features: • Graphics displayed very quickly • Large hard disk • Game controller, e.g. joysticks, buttons • Internet connection for online games. • Embedded computer – designed for and built into equipment to perform specialised functions, e.g. a single microchip that controls a DVD player. Processors A processor or microprocessor is built into a microchip that also has memory and other components built into it. The microchip itself is often referred to as the ‘processor’. If there is more than one processor built into the microchip, then the microchip is referred to as the ‘processor’ and processors built into it are referred to as ‘cores’. An important feature of a processor is the speed at which it processes instructions. If you have more and faster cores, with a larger on-board cache, applications will run more quickly. Here is a microprocessor description: Intel Core 2 Duo E8600 Processor (3.33GHz, 1333MHz FSB, 6MB cache). This has two cores and their speed is 3.33GHz. The front side bus (FSB) transfers data between the processor and memory at a speed of 1333MHz. A 6MB cache of RAM memory is built into the microprocessor. Figure 1.2 An Intel Core 2 Duo microprocessor Page 2 of 40 3 Chapter 1: Hardware The processor you need depends on what you are going to do. For occasional word processing and email, an Intel Pentium Dual Core processor might be sufficient but for playing online multimedia games a faster Intel Pentium Quad Core processor is needed. Input and output devices • The peripheral devices attached to a computer system are for input, output or storage. • An input device is for putting in data to the computer. • An output device displays information from the computer. Input device Output device Keyboard Monitor Mouse Printer Scanner Speakers and headphones Input devices Keyboards A QWERTY keyboard is used with most PCs and laptops. To use a keyboard efficiently, you need to know the layout and be able to touch- type. Numeric keyboards only have keys to input numbers and special characters. An example of a numeric keypad is an automated teller machine (ATM), also known as a cashpoint. Pointing devices Compared with a keyboard, pointing devices make it easier to point and click but are harder to use to input text. • Mouse – an optical mouse detects movement using light but some do this using a small rubber ball. • Joystick – a lever that gives you similar control to a mouse. Joysticks are built into game consoles, which are mainly used for input but may have limited output, e.g. they vibrate. • Tracker ball – like an upside-down ball mouse with the ball on the top. Move the ball with your thumb. • Trackpad – a pad below the space bar on a laptop. Move your fingers across its surface and the pointer moves on the screen. • Graphics tablet – a flat rectangular pad 15 to 76 cm (6 to 30 inches) wide. Move a stylus along its surface to produce line drawings. Mainly used for computer-aided design. Figure 1.3 An automated teller machine (ATM) or cashpoint showing the numeric keypad Figure 1.4 Graphics tablet and puck being used to trace a drawing Page 3 of 40 4 Chapter 1: Hardware Scanners A scanner converts printed images on paper into electronic form: • Hand-held scanner – reads the image while being dragged over it. • Flatbed scanner – the image is laid fl at on the scanner’s surface. • Sheet-fed scanner – reads the image as the paper goes through the sheet feeder. Scanners may read only particular types of image, e.g. a bar code scanner. Optical Mark Recognition (OMR) An OMR reader recognises a mark made on paper so there is no need to type in the data. The mark’s position determines its meaning. Marks must be very clear, or they may not be recognised. Optical Character Recognition (OCR) OCR is used to input printed or handwritten characters without typing in the data. The characters are converted to text that can be word processed. This text needs to be checked carefully as character recognition is not always accurate. Magnetic ink character recognition (MICR) MICR is used to input specially shaped characters printed in magnetic ink. Forms can be pre-printed with data which can be read by a computer, but printing in magnetic ink is more expensive. OCR vs MICR • OCR and MICR both read printed characters. • OCR uses refl ected light while MICR uses magnetic fi eld patterns. • OCR recognises handwriting and different types of printed text but MICR only recognises specially shaped characters. Figure 1.5 A bar code scanner Figure 1.6 MICR uses uniquely shaped characters printed in magnetic ink When you describe the difference between two technologies, each point you make should mention both technologies. TOP TIP ✓ Page 4 of 40 5 Chapter 1: Hardware Magnetic stripe cards • Information is stored on a magnetic stripe on a plastic card. The data recorded on the magnetic stripe can be input directly into a computer. Stripe cards can be used to control access. A disadvantage of stripe cards is that the data may be affected by electromagnetic radiation and data can also be copied or edited. Smart cards • A smart card is a plastic card with a microprocessor chip embedded in it. • Bank and credit cards are usually smart cards, i.e. Chip and PIN (personal identification number) cards. • They are used to pay for goods in shops and to withdraw cash at cashpoints. Cashpoints are specialised computer terminals with a small screen, numeric keyboard and smart card reader. • Oyster® cards are smart cards in widespread use in London to pay for travel. They are preloaded with cash credits online. • Smart cards can also be affected by electronic radiation and can be copied or edited but they are generally more secure than data recorded on a magnetic stripe. Digital cameras, digital video cameras and webcams • A digital camera stores pictures on a memory card. These can be transferred to a computer or TV . Digital cameras have a small LCD screen or traditional viewfinder. The camera forms pictures from a mass of very small dots of different colours. Picture quality is related to the density of the dots. • A digital video camera or camcorder records moving images with sound. Recordings can be saved on a memory card or built-in hard uploads/Geographie/ ict-revision-guide.pdf