Types of Hardware Devices

Power supply(S.M.P.S)Switch Mode Power Supply

A case that holds a transformer, voltage control, and (usually) a cooling fan, and supplies power to the rest of the computer such as For Motherboard,CD-rom,R/w,Floppy drive etc

Storage controllers

Controllers for hard disk, CD-ROM and other drives like internal Zip and Jaz conventionally for a PC are IDE/ATA; the controllers sit directly on the motherboard (on-board) or on expansion cards, such as a Disk array controller. IDE is usually integrated, unlike SCSI which is found in most servers. The floppy drive interface is a legacy MFM interface which is now slowly disappearing. All these interfaces are gradually being phased out to be replaced by SATA and SAS.

Video display controller

It Produces the output for the computer display. This will either be built into the motherboard or attached in its own separate slot (PCI, PCI-E or AGP), in the form of a Graphics Card.

Removable media devicesCD - the most common type of removable media, inexpensive but has a short life-span. CD-ROM Drive - a device used for reading data from a CD. CD Writer - a device used for both reading and writing data to and from a CD. DVD - a popular type of removable media that is the same dimensions as a CD but stores upto 6 times as much information. It is the most common way of transfering digital video. DVD-ROM Drive - a device used for reading data from a DVD. DVD Writer - a device used for both reading and writing data to and from a DVD. DVD-RAM Drive - a device used for rapid writing and reading of data from a special type of DVD. Blu-ray - a high-density optical disc format for the storage of digital information, including high-definition video. Currently a rival of HD DVD. BD-ROM Drive - a device used for reading data from a Blu-ray disc. BD Writer - a device used for both reading and writing data to and from a Blu-ray disc. HD DVD - a high-density optical disc format and successor to the standard DVD. Currently a rival of Blu-ray Floppy disk - an outdated storage device consisting of a thin disk of a flexible magnetic storage medium. Zip drive - an outdated medium-capacity removable disk storage system, first introduced by Iomega in 1994. USB flash drive - a flash memory data storage device integrated with a USB interface, typically small, lightweight, removable and rewritable. Tape drive - a device that reads and writes data on a magentic tape, usually used for long term storage.
Internal storageHardware that keeps data inside the computer for later use and remains persistent even when the computer has no power.

Hard disk

It is use for medium-term storage of data. Solid state drive - a device emulating a hard disk, but containing no moving parts. Disk array controller - a device to manage several hard disks, to achieve performance or reliability improvement.

Sound card

It Enables the computer to output sound to audio devices, as well as accept input from a microphone. Most modern computers have sound cards built-in to the motherboard, though it is common for a user to install a separate sound card as an upgrade.

NetworkingConnects the computer to the Internet and/or other computers.

Modem

It is use for dial-up connections Network card - for DSL/Cable internet, and/or connecting to other computers. Direct Cable Connection - Use of a null modem, connecting two computers together using their serial ports or a Laplink Cable, connecting two computers together with their parallel ports.
Other peripheralsIn addition, hardware can include external components of a computer system. The following are either standard or very common.

Wheel mouseIncludes various input and output devices, usually external to the computer system

InputText input devices Keyboard - a device to input text and characters by depressing buttons (refered to as keys), similar to a typewriter. Pointing devices Mouse - a pointing device that detects two dimensional motion relative to its supporting surface. Trackball - a pointing device consisting of an exposed portruding ball housed in a socket that detects rotation about two axes.

Gaming devices Joystick - a general control device that consists of a handheld stick that pivots around one end two detect angles in two or three dimensions. Gamepad - a general game controller held in the hand that relies on the digits (especially thumbs) to provide input. Game controller - a specific type of controller specialized for certain gaming purposes. Image, Video input devices Image scanner - a device that provides input by analyzing images, printed text, handwriting, or an object. Webcam - a low resolution video camera used to provide visual input that can be easily transfered over the internet. Audio input devices Microphone - an accoustic sensor that provides input by converting sound into an electrical signal

OutputImage, Video output devices Printer - a peripheral device that produces a hard (usually paper) copy of a document. Monitor - device that displays a video signal, similar to a television, to provide the user with information and an interface with which to interact. Audio output devices Speakers - a device that converts analog audio signals into the equivalent air vibrations in order to make audible sound. Headset - a device similar in functionality to computer speakers used mainly to not disturb others nearby.

Hardware Description

Motherboard

The motherboard is the "heart" of the computer, through which all other components interface.
Central processing unit (CPU) - Performs most of the calculations which enable a computer to function, sometimes referred to as the "brain" of the computer. Computer fan - Used to lower the temperature of the computer; a fan is almost always attached to the CPU, and the computer case will generally have several fans to maintain a constant airflow. Random Access Memory (RAM) - Fast-access memory that is cleared when the computer is powered-down. RAM attaches directly to the motherboard, and is used to store programs that are currently running. Firmware is loaded from the Read only memory ROM run from the Basic Input-Output System (BIOS) or in newer systems Extensible Firmware Interface (EFI) compliant Internal Buses - Connections to various internal components. PCI PCI-E USB HyperTransport
CSI (expected in 2008)
AGP (being phased out)
VLB (outdated)
ISA (outdated)
EISA (outdated)
MCA (outdated)
External Bus Controllers - used to connect to external peripherals, such as printers and input devices. These ports may also be based upon expansion cards, attached to the internal buses. Parallel port
Serial port
USB
Firewire
SCSI (On Servers and older machines)
PS/2 (For mice and keyboards, being phased out and replaced by USB.)

Types of various Software

Practical computer system is divide software systems into three major classes:- System software, Programming software & application software, although the distinction is arbitrary, and often blurred.

System software helps run the computer hardware and computer system. It includes operating systems, device drivers, diagnostic tools, servers, windowing systems, utilities and more. The purpose of systems software is to insulate the applications programmer as much as possible from the details of the particular computer complex being used, especially memory and other hardware features, and such accessory devices as communications, printers, readers, displays, keyboards, etc.

Programming software usually provides tools to assist a programmer in writing computer programs and software using different programming languages in a more convenient way. The tools include text editors, compilers, interpreters, linkers, debuggers, and so on. An Integrated development environment (IDE) merges those tools into a software bundle, and a programmer may not need to type multiple commands for compiling, interpreter, debugging, tracing, and etc., because the IDE usually has an advanced graphical user interface, or GUI.

Application software allows end users to accomplish one or more specific (non-computer related) tasks. Typical applications include industrial automation, business software, educational software, medical software, databases, and computer games. Businesses are probably the biggest users of application software, but almost every field of human activity now uses some form of application software. It is used to automate all sorts of functions.

Computer Software

Computer software is so called in contrast to computer hardware, which encompasses the physical interconnections and devices required to store and execute (or run) the software. In computers, software is loaded into RAM and executed in the central processing unit. At the lowest level, software consists of a machine language specific to an individual processor. A machine language consists of groups of binary values signifying processor instructions (object code), which change the state of the computer from its preceding state. Software is an ordered sequence of instructions for changing the state of the computer hardware in a particular sequence. It is usually written in high-level programming languages that are easier and more efficient for humans to use (closer to natural language) than machine language. High-level languages are compiled or interpreted into machine language object code. Software may also be written in an assembly language, essentially, a mnemonic representation of a machine language using a natural language alphabet. Assembly language must be assembled into object code via an assembler.

Computer Harware

Computer hardware is the physical part of a computer, including the digital circuitry, as distinguished from the computer software that executes within the hardware. The hardware of a computer is infrequently changed, in comparison with software and data, which are "soft" in the sense that they are readily created, modified or erased on the computer. Firmware is a special type of software that rarely, if ever, needs to be changed and so is stored on hardware devices such as read-only memory (ROM) where it is not readily changed (and is, therefore, "firm" rather than just "soft").
Most computer hardware is not seen by normal users. It is in embedded systems in automobiles, microwave ovens, electrocardiograph machines, compact disc players, and other devices. Personal computers, the computer hardware familiar to most people, form only a small minority.