DESKTOP AND NOTEBOOK Most personal computers are either desktop PCs (Personal Computers) or notebook PCs . The desktop PC can be found in every company and in most homes. The notebook PC, sometimes called a laptop PC, is a self-contained portable PC designed for mobility use.
Hardware Hardware refers to physical components that make up a computer system. Basically, anything you can see and touch, and would likely break if you threw it out a fifth-story window, is hardware. Examples of hardware are monitor, keyboard, mouse and printer . Hardware also includes the computer’s processor, memory, Hard disk, floppy disk, CD ROM, monitor, keyboard, printer and so on.
Software Software controls the computer hardware and makes it do useful work. Without software a computer is useless machine. Software is the programs and data that a computer uses to carry out certain tasks but it itself is intangible (elusive). Software is kept or store on some hardware device like hard disk or floppy disk. Types of Software:
Operating System Operating System is the most important program that runs on a computer. Every general purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers. For examples Windows Vista, Linux and UNIX
For most of the computer users, what is inside the system unit is a mystery. The system unit is the actual computer; everything else is called a peripheral device . The big box that contains the processing circuitry and storage devices is a crucial part of a computer, without it computer won’t work.
THREE STAGES OF COMPUTING INPUT OUTPUT PROCESSING
INPUT Input is a process in which information is entered into a computer for processing, as from a keyboard or from a file stored on a disk drive. Data entered into the computer via some sort of input device such as the drive, lightpen, keyboard, microphone, mouse, modem, or scanner.
PROCESSING Processing is very important part of a computer. It is also called as “Central Processing Unit (CPU)", is the pretty much the brain of your computer. It processes everything from basic instructions to complex functions. The CPU processes information, performing arithmetic calculation and making basic decisions by comparing information values. Any time something needs to be calculated, it gets sent to the CPU.
OUTPUT Output is information that has been manipulated by the Central Processing Unit (CPU) of the computer and displayed either on the video monitor or printed on paper or film as hard copy or saved on disk in a digital format. Output devices are machines that display information from the computer. Examples of output devices are the monitor and the speakers. Printers are also examples of output devices.
HOW COMPUTER WORKS From the previous three sections you have learned that input devices feed information into the computer, the CPU processes the information and the output devices translate this information back to the user in a form that is easily understood. The smallest unit of information on a computer, the 0's and 1's are referred to as bits. A byte is a combination of 8 bits. All the input supplied to CPU via input devices will changed to binary numbers. Microprocessor processes binary number depending on the program (software) function and send the processed information to output device. The output device like monitor visually show the output where as printer will print on a paper.
EXTERNAL CONNECTION In order to make computer more useful and have more functionality, there must be way to get the data into and out of a computer. To facilitate input/output process computer has different types of ports and connectors. Most common types of connectors and ports are: Serial Parallel Universal Serial Bus(USB) Video Ethernet Sound in/out Game ports
MINI DIN CONNECTOR The original DIN connector was replaced by mini-DIN a long time ago. Most of modern PC has mini-DIN where you can plug your keyboard and mouse .
USB CONNECTOR USB can connect peripherals such as mouse devices, keyboards, joysticks, scanners, digital cameras, printers, external storage, networking components, etc. It is becoming more common and popular choice for connecting computer peripherals
The USB B connector's relatively large size makes it less than optimal for small devices such as cameras. There is smaller mini-B-style connector suitable for small devices like camera and MP3/MP4 players.
FIREWIRE CONNECTOR FireWire consists of 6-wire connector, used for moving data at incredibly high speed, making it the perfect connection for highly specialized applications like streaming videos.
DB connector DB connectors have a slight D shape and used for almost any type of peripheral you can think of except keyboards. Each male DB plug has group of small pins that connect to DB ports. Female DB plugs connect to male DB ports on the system unit. DB connectors have 9 to 37 pins of sockets, although it is rare to see DB connector more than 25 pins.
AUDIO CONNECTOR The most common type of sound connector uses the mini-audio connector, which is found at the system unit of computer. These connectors are used for connecting speaker and microphone.
RJ CONNECTORS The little plastic plug used to connect your telephone cord to the jack is called RJ-11 connector . Slightly bigger than telephone connector is Ethernet connector which is called as RJ-45 connector . Modern PCs uses both RJ-11 to connect to modem and RJ-45 to connect to Local Area Network (LAN).
VGA CONNECTOR VGA connector is used to connect monitor to the system unit. There are two types of Video Graphic Array (VGA) connector , older 15-pin female DB VGA connector or the unique Digital Video Interface (DVI) connector . There is mini-DIN connector, such as S-Video that can connect to TV or video camera.
The newest type of video connector called High-Definition Multimedia Interface (HDMI) has ability to carry both video and audio on the same cable.
PRINTER PORT The printer uses special 25-pin female DB connector called a parallel port . Almost 20 years of domination by parallel ports for connecting printer, now printer come with USB port or even with FireWire.
SERIAL PORT Traditionally the external modem connects to a male 9-pin or 25-pin DB port of system unit called serial port . Today most of external modem connects to USB.