HARDWARE

Raw information to be processed DATA Raw information to be processed

Information is data that people can understand.

When data is typed in or otherwise entered into the computer. input When data is typed in or otherwise entered into the computer.

output When the computer displays text or graphics on the screen, prints, plays sounds or otherwise communicates to the user.

processing The computer processes data, just as we could process our ingredient to get a tasty cooked meal. Think of the computer program as a recipe with instructions to follow. Raw food goes in as input and, after processing, out comes the well- baked dish.

A computer not only processes data, but can store or save it too.

What is a computer?

computer

A computer is a programmable machine.

hardware Hardware is the physical parts of the computer system – the parts that you can touch and see. A motherboard, a CPU, a keyboard and a monitor are all items of hardware.

Computers come in all sorts of shapes and sizes. Types of computer Computers come in all sorts of shapes and sizes. 

Computers can be grouped into: Microcomputer Mainframe computer Minicomputer Supercomputer

Microcomputer It is usually for individual use, and so it is called a personal computer (PC).

Mainframe computer It is large expensive computer, with huge processing power. It is used by many people at the same time and to carry out intensive tasks.

It is a smaller version of a mainframe computer. Minicomputer It is a smaller version of a mainframe computer.

It is very large mainframe computers. Supercomputer It is very large mainframe computers.

Different types of pc

Personal computer A desktop PC usually has these basic components: Monitor Keyboard A system unit (CPU) Mouse

laptop A laptop computer is about the size of an A4 file. Laptops are increasingly becoming lighter and more potable.

tablet A tablet computer is a laptop computer with a sensitive touch screen that can be used instead of the keyboard.

notebook A notebook computer is a small laptop computer that is about as big as an oversized book. A notebook computer is likely to be half the size of a laptop and is light and easy to carry.

Personal digital assistant(PDA) PDA can fit in one hand or in a pocket, but it is too small for general work. A PDA has a touch- sensitive screen. Although PDAs can be temporarily attached to a keyboard, but we cannot comfortably type a long document into a PDA. A smart phone is a mobile phone with the functions of a PDA.

Input and output devices There are many devices for putting information into the computer and for displaying the information that is output. The peripheral devices attached to a computer system are for input, output or storage.

Input devices Input devices accept data signals, and translate them for usage and storage in the computer system.

keyboards There are different types of Keyboards: QWERTY keyboard. Concept keyboard.

KEYBOARD Advantage : Keyboards are almost always available as an input device. They are widely used at work. Many people know how to use a QWERTY keyboard.

Disadvantage : To use a keyboard efficiently, we need to know the layout and be able to touch- type.

concept keyboard a concept keyboard has a flat touch-sensitive surface. A plastic overlay is placed over this surface. Different regions of the surface is programmed to act as keys Used by people with disabilities, at supermarkets cash points.

Concept keyboard

Concept keyboard

Laptop Desktop Individual unit I/O devices are separately connected to the system. Lighter and portable Heavy and not portable Less expensive More expensive

Pointing devices Pointing devices are used for pointing to and selecting objects on the monitor screen. E.g. Mouse, joystick, tracker ball, light pen

scanner A scanner is an input device that reads printed data (text, pictures) into the computer. Different types of scanners are: A hand-held scanner reads in the data while being dragged over it. A flatbed scanner reads in the data that is laid on the scanner’s flat surface and is captured into the computer. A sheet-fed scanner reads the data from the paper as it goes through the device.

Light pen Light pen is an input device like a pen that can be used to draw on the computer screen or to point at objects.

Sensors Sensors are input devices used to input data about the environment into the computer. E.g. light sensor, temperature sensor, pressure sensor.

Monitor Monitor is the Visual Display Unit of the computer. Three types of monitors are: Cathode Ray Tube (CRT) monitors Liquid Crystal Display (LCD) monitors Touch Screen

printers Ink Jet Printer Laser Printer It works by spraying ink onto a page. It uses laser light to make patterns. Less Expensive and slow in speed More Expensive and prints quickly Print quality is lesser than laser print outs. Gives excellent quality pictures. It is based on liquid ink. Laser is based on thermal technology. Ink cartridges needs to be replaced often. Toner of the laser Printer need not to change much often