Wednesday, January 22

What is Computer Hardware?

Computer hardware are the collection of all the physical or tangible parts that make up a computer system. In other word all the physical parts of computer which can be touched or felt are known as hardware. They are peripheral devices used in computer for specific purpose. Some examples of hardware are keyboard, mouse, monitor, CPU, ROM, RAM etc. Some computer hardware described below.

Keyboard: Keyboard is an input device. It is set of typewriter like keys that enables user to enter data into a computer. Keyboard consist of set of alphabets (A-Z), digits (0,1,2,………9) symbols and functional and control key. When a key is press, an electrical signal produces and it is detect by electronic circuit called keyboard encoder and converted to binary code. Keyboard is also called QWERTY because first six keys on the top row of keyboard contains letter QWERTY.

Mouse: Mouse is an input device that is most often used with a personal computer. Moving a mouse along a flat surface can move the on-screen cursor to different items on the screen. Items can be moved or selected by pressing the mouse buttons (called clicking).    There are two types of mouse they are: mechanical mouse and optical mouse.

Scanner: Scanner is an input device which allows capturing drawing or photographing from hardcopy sources like paper, into electronic form. Using scanner drawings, graphs, photos, text can be converted to digital form by passing optical mechanism.

Joystick: A joystick is an input device that can be used for controlling the movement of the cursor or a pointer in a computer device. The pointer/cursor movement is controlled by direction a lever on the joystick. The input device is mostly used for gaming applications and, sometimes in graphics applications.

Light Pen: A light pen is a light-sensitive computer input device, basically a stylus (like pen), that is used to select text; draw pictures and interact with user interface elements on a computer screen or monitor. It is made of photocell placed in a pen shaped tube which detects the light emitted from the screen.

CPU(Central Processing Unit) :

Processing unit controls and directs all the operation and components of computer system. It is the heart of computer system. It is linked with various peripheral devices like input/out devices, storage devices and so on. Processing unit performs logical comparison, mathematical computation, executes statements and transfer information to different parts of computer.  Processing unit consists of three parts, they are following.

MICR: MICR stands for “Magnetic Ink Character Recognition”. It is a character recognition system that uses special ink and characters. When a document that contains this ink needs to be read, it passes through a machine, which magnetizes the ink and then translates the magnetic information into characters.

Trackball: Trackball is an input device which uses a ball that can rotate in any direction. The user spins (घुमाउनु) the ball in different directions to move the cursor on the screen. An associated electronic circuit detects the direction and speed of the spin.

Monitor: Monitor is an output device of computer that is used to display any types of data and information from computer. It is also known as softcopy output device.  There are different types of monitor they are: CRT, LCD, LED etc.

Printer: A printer is an output device that accepts text and graphic output from a computer and transfers the information to paper, usually to standard size sheets of paper.  It is also known as hardcopy output device.   Printers provide information in a permanent readable form. The printer can be classified into two categories on the way how they print. They are impact printer and non-impact printer.

Plotter: Plotter is the output device used to produce real and good quality graphics and drawing under computer controls. It use ink pen or ink-jet to draw graphics or drawing. Either single color or multicolor pens can be used. It is specially used in scientific and engineering fields. 

Speaker: A speaker is an output device   that connects to a computer to generate sound. The signal used to produce the sound that comes from a computer speaker is created by the computer’s sound card.

Modem: Modem is a communicating device of computer system that used to transmit data and information over a standard telephone line. It has two part, modulator and demodulator. Modulator converts digital signal into analog and demodulator converts analog signal into digital signal. Modem converts input signal into digital and output signal into analog. There are two types of modem, they are: Internal and external modem.

USB: USB is a connecting device of a computer which has higher data transfer rate. It allows interfacing several devices to a single port in a daisy chain ( to link  together in series).It provides interface(जोड्ने बिन्दु ) for peripherals like mouse, keyboard, modem , speaker, printer etc. It provides power lines along with data lines.

RAM: RAM stands for “Random Access Memory” and is the primary memory of computer which is making up of semiconductor chips. This is temporary storage because data and instruction stored in RAM remains as long as power is on. So this is also called the volatile memory. There are two types of RAM, they are:  SRAM and DRAM.

ROM: ROM stands for “Read Only Memory”. ROM is the primary memory of    computer where data and instructions are permanently written. It is a non-volatile memory in which data is stored permanently and cannot be changed by usual programs. ROM is mainly used to store the programs that do not and frequently used. The program stored in ROM is called firmware. Firmware is written by manufactures at manufacturing time.  There are three types of ROM they are: PROM, EPROM, EEPROM.

Hard Disk: Hard disk is a storage device used to store and provides relatively quick access to the large volume of data on electromagnetically charged surfaces.  Hard disk is both input and output device since data can be both stored and retrieved from it. It is non-volatile in nature and is mainly used to store large volume of data permanently. It has read/write facility.  Data in hard disk can be accessed randomly. The main components in hard disk are platters. Platters made up of aluminum coated with iron-oxide on both sides to stored data magnetically.  A hard disk has a storage capacity in terms of gigabyte.

Floppy Disk: Floppy disk is a removable disk so it can be used to transfer small amount of data from one computer to another. The disk is enclosed in a protective plastic cover called disk jacket to protect disk from external damage. Floppy disks are portable magnetic device. It is read/write memory. Data in floppy disk can be accessed randomly.

Flash Memory: Flash memory is a memory storage device for computers and electronics. It is most often used in devices like digital cameras, USB flash drives, and video games. It is quite similar to EEPROM. Flash memory is one kind of Non-volatile random-access memory. It is slower than RAM but faster than hard drives. It is much used in small electronics because it is small and has no moving parts.

Pen Drive: A pen drive, or a USB flash drive, is a portable data-storage device. Pen drives have replaced the floppy drives of old and have become the most popular data-storage devices among consumers. Micro, lightweight and handy, a pen drive can be easily carried and easily transfer data and files from one computer to another computer. Storage capacity of pen drive is MB to GB.

Memory Card: Memory card is a type of storage media that is often used to store photos, videos, or other data in electronic devices. Devices that commonly use a memory card include digital cameras, handheld computers, MP3 players, PDAs, cell phones etc. It is non-volatile memory. There are a handful of different types of memory cards on the market, each varying in size, compatibility, and storage capacity.

DVD: DVD stands for “Digital Versatile Disc“. The DVD can store any kind of digital data and is widely used for software and other computer files as well as video programs watched using DVD players. DVDs offer higher storage capacity than compact discs while having the same dimensions. It can store any type of data such as text, audio-video, graphics etc. Examples of DVD are DVD R, DVD ROM etc.

Blue-Ray Disc: Blue-ray Disc (BD) is a digital optical disc data storage format. It was designed to replace the DVD format, in that it is capable of storing hours of video in high-definition (HDTV 720p and 1080p) and ultra high-definition resolution.

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