In this topic we discuss the major hardware components of a microcomputer system, which are used for input, output, processing, storage, electrical supply and communication.

  Most input and output devices are outside the computer case.  Most processing and storage components are contained inside the case.  The most important component in the case is the central processing unit (CPU) is called the processor and microprocessor.

  As its name implies, the device is central to all processing done by the computer.  Data received by input devices is read by the cpu , and output from the cpu is written to output devices.   The cpu writes data and instruction in storage devices and performs calculation and other data processing.

 Whether inside or outside the case and regardless of the function the device performs,  each hardware input, output, or storage device require these elements to operate:

A method for the CPU to communicate with the device

·        The device sends data to or receives data from the CPU.  The CPU might need to control the device by passing instruction to it or the device might need to request service from the CPU.
·        Software to instruct and control the device.
·        A device is useless without software to control it.  The software must know how to communicate with the device at the detailed level of the specific device, and the cpu must have access to this software in order to interact with the device.  Each device responds to a specific set of instructions based on the devices functions.  The software must have an instruction for each possible action you expect the device to accomplish.
·        Electricity to power the device
·        Electronic devices require electricity to operate.  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.


An input device is any device that provides input to a computer.  There are dozens of possible input devices but the two most common ones are a keyboard and mouse.  Every key you press on the keyboard and every movement or click you make with the mouse sends a specific input signal to the computer.

  These commands allow you to open programs, type messages, drag objects, and perform many other functions on your computer.

Since the job of a computer is primarily to process input, computers are pretty useless without input devices.  Just imagine how much fun you would have using your computer without a keyboard  or mouse.  Therefore, input devices are a vital part of the computer system.

While most computer come with a keyboard and mouse, other input devices may also be used to send information to the computer.  Some examples include joysticks, MIDI keyboards, microphones, scanners, digital cameras, webcams, card readers, UPC scanners, and scientific measuring equipment.

  All these devices send information to the computer and therefore are categorized as input devices.  Peripherals that output data from the computer are called output devices.

KEYBOARD – The keyboard is the primary input device of a computer.  The keyboard that are standard today are called enhanced keyboard and hold 104 keys.  
Ergonomic keyboards are curved to make them more comfortable for hands and wrists.

In addition, some keyboards come equipped with a mouse port used to attach a mouse to the keyboard, although it is more common for the mouse port to be on the computer case.  Electricity to run the keyboard comes from inside the computer case and is provided by the wires in the keyboard cable.

MOUSE – A mouse is a pointing device used to move a pointer on the screen and to make selections.  The bottom of the mouse has a rotating ball or an optical sensor that
tracks movements and controls the location of the pointer.  The one two or three buttons on the top of the mouse serve different purposes for different software.  Windows vista uses the left mouse button to execute a command and the right mouse button display a shortcut menu of commands related to the item.

TOUCH SCREEN – Touch screen is a monitor or other flat surface with sensitive panel directly on the screen that registers the touch of a finger as input.  Instead of being touch sensitive, some touch screens also use beams across the screen to create a grid that is interrupted by a presence of finger near the screen.

A touch screen allows a user to interact with a device without mouse or keyboard for input and is often used in public environment where the users may only need to access the general information, such as direction to a room in a building.

SCANNER An optical scanner is a hardware input device that allows a user to take on image or text and convert it into a digital file, allowing the computer to read or display the scanned object.  A scanner can be connected to a computer using USB, firewire, parallel or SCSI port.

Other scanners include: sheetfed scanner, which is a scanner that scans paper fed into it, handheld scanner, which is a scanner that held and drag on the page that is used to scan it, and a card scanner, which is a small scanner capable of scanning business cards.

BAR CODE READER –Barcode lines of different widths and sizes representing data and read will determine what the scanned object is.  Barcodes are often used to organize and index information or prices about an object.  Barcode used by the U.S. postal service that helps speed the delivery of mail is another perfect example about how are barcode codes is used.  Barcodes are widely used by supermarket to price the goods.

A KVM switch is a hardware device that allows a user to control multiple computers from one or more keyboard, video monitor and mouse.  Although multiple computers are connected to the KVM, typical a smaller number of computers can be controlled at any given time.  Modern devices have also the added the ability to share other peripherals like USB devices and audio.

MICROPHONE –A microphone is a hardware peripheral originally invented by Emile Berliner in 1877 that allows computer users to input audio into their computers.

When referring to the computers and security, biometrics is the identification of a person by the measurement of the biological features.  For example, a user identifying them a computer or building by their finger print or voice is considered biometrics identification.  When compared to a password, this type of system is much difficult to fake since it is unique to the person.  Below is a listing of all known biometric devices.   Other common methods of a biometrics scan are a person’s hand, face, iris and retina.

A gamepad, game controller or video game controller is a peripheral device designed to be connected to a computer or console gaming system.  It has multiple buttons and may have one or two mini joysticks.  A gamepad is used for playing video games of many types, including sports, first person shooters, role playing and others.  Gamepads is the primary peripheral device used for console gaming like xbox 360, play station 3 and Nintendo w2


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