Major Personal Computer

Hardware Components

Used for input, output, processing, and storage, as well as components that allowcommunications within the computer and

provide an electrical supply.

Computer Case

Most input and output devices are outside the computer case, while most processing, storage, communication, and power supply components are contained inside the computer case.

Are all computer cases the same?

Computer cases for personal computers and notebooks fall into three major categories:

• desktop cases, • tower cases, • and notebook cases.

The desktop case sits horizontally on a desktop, often under a monitor. The tower case, which usually sits vertically under the desk, isone to two feet tall. The notebook case is used for notebook computers (also referred to as laptop computers).

CENTRAL PROCESSING UNIT (CPU)

The most important component inside the case is the central processing unit (CPU), also called the microprocessor or processor. As its name implies, the CPU is central to all processing done by the computer. The CPU reads and writes data and instructions to and from storage devices and performs calculations and other data processing.

CPUMany other computer components also must communicate with the CPU. In fact, each hardware input, output, or storage device requires these elements to operate:

• A method to communicate with the CPU.• Software to instruct and control the device.• Electricity to power the device.

A Method to Communicate with the CPU

Every device must have a way to send or receive data to and from the CPU. The CPU might need to control the device by passing instructions to it, or the device might need to request service from the CPU.

A device is useless without software to control it. Each device responds to a specific set of instructions based on its particular functions. The software must have an instruction for each possible action the device is expected to perform, and the software must know how to communicate with a device at the level required by the device. The CPU also must have access to this software in order to interact with the device.

Software to Instruct and Control the Device

Electricity to Power the Device

Devices can receive power from the power supply inside the computer case, or they can have their own power supplied by a power cable connected to an electrical outlet.

Outside the Computer CaseMost input and output devices reside outside the computer case.

PortInput and output devices communicate with components inside the computer case through a wireless connection or through cables attached to the case at a connection called a port.

A port is a physical connector that allows a cable from a peripheral device to be attached to the computer.

Peripheral Device

A peripheral device such as a keyboard, mouse, monitor, or printer, is a device that is not located directly on the motherboard but communicates with the CPU. Peripheral devices often are connected to the computer’s motherboard via a port or wireless connection.

Input and output devices connect to the computer via ports usually found on the back of the computer case. For wireless connections, a wireless device communicates with the system using radio frequency (RF) technology or an infrared port.

Most likely in front of you right now are two of the most popular input devices: the keyboard and the mouse. And instead of a mouse on a laptop computer you normally have a touchpad.

Different people prefer different input devices for doing same task. For instance, many graphic artists prefer to use a stylus and graphics tablet rather than a mouse. It might offer them a greater deal of artistic freedom, or precision while performing their work.

Input Devices

Sufferers of carpal tunnel syndrome often prefer a trackball or stylus to a mouse. Handicapped computer users have invented a wide array of input devices designed to replace the mouse including devices controlled by foot or even eye movement. Not only PCs and mainframes use input devices. Almost all computers feature some kind of input device. Special scanners are used in many stores and warehouses called barcode readers to enter stock and sell items at the cashier. These are input devices as well. Even microphones can technically be called input devices as a computer can respond to them and interpret them as incoming data.

The Future of Input Devices

Corporations and especially government institutions are already implementing the second generation of input devices to improve security. These include retina scanners and/or fingerprint readers to replace or improve accuracy of username and password authentication. You will be seeing more of this kind of biometric authentication in the coming years as a general remedy for weak passwords or leaked passwords.

Output Devices

The monitor and the printer are the two most widely used output devices. The monitor visually displays the output of the computer. The monitor is described by the size of its screen in inches (measured diagonally) and the monitor’s resolution. Resolution refers to the sharpness and clearness of an image. The monitor’s resolution is a function of the number of dots, or pixels, used for display. The greater the number of pixels in an image, the higher the resolution of the image.