What is Computer Hardware? | Introduction to Computer

COMPUTER HARDWARE

Computers made up of pieces of electronic circuits for performing calculations. Hardware of a computer consists of electronic devices, the parts we can see and touch. The term device refers to any piece of hardware used by the computer, such as a keyboard, monitor, mouse etc. Various hardware parts inside computer cabinet are: motherboard, ports and interfaces, expansion slots, ribbon cables, memory chips, storage devices, processor.

Hardware Parts of a Computer System:

• Motherboard
• CPU
• Bus
• Storage (Memory)
• Input/Output devices
• Storage devices (Disks)
• Graphics
• 3D
• Sound card
• Video card
• CD/DVD Writer
• Network cards
• Ports

One of the most important parts of the computer is motherboard. It is the backbone of entire computer system. Also motherboard is responsible for the characteristics of a computer. Computer can also be defined by its motherboard. Motherboard holds all the important components (Processor, Circuitry, and Memory) that define computer system. Also have provisions to put graphic, sound, network cards, peripherals etc. The CPU is also called the Processor. It manages all the devices and performs actual processing of data. Examples of CPUs are:

• Pentium
• PIV
• Pentium Dual Core
• Core2Duo
• Corei3, Corei5, Corei7

BUS

Buses are interconnecting units of a computer. Buses can be broadly classified as:

• System bus (Internal bus)
• Expansion bus
• External ports

System bus: connects components inside the motherboard like CPU. System bus consists of address, data and Control bus. Address of I/O device or memory is carried by the address bus. Data to be transferred is carried by the data bus. Command to access memory or I/O device is carried by the control bus.

External Bus: Expansion bus connects external devices to the computer. It connects different external devices, peripherals, expansion slots, I/O ports and drive connections to the rest of the computer. External bus is also known as expansion bus. The external devices like Monitor, Keyboard, and Printer connect to Ports on the back of computer.

Input devices accept data and instructions from the user. The keyboard and mouse are examples of input devices. Output devices return processed data back to the user. The monitor and printer are examples.

Memory & Storage

Memory consists of chips (RAM and ROM) attached to the motherboard. Memory devices can be classified as cache memory, primary memory, and secondary memory.

Storage devices hold data not currently being used by CPU. Data is commonly stored on a magnetic or optical disk. Each type uses a special medium for storing data on its surface. A disk drive is a device that reads data from and writes data to a disk. Most modern computers feature a hard disk drive and an optical disk drive. The most common storage devices are: CDROM and DVD-ROM drives.

• Hard disk
• CD-ROM, DVD
• Flash memory (Pen drives)
• Floppy disk
• Tape drive

PORTS

Port serves as contact point between computer and I/O devices. Computer can send or receive data using these ports. Examples of various ports are: keyboard ports, mouse ports, USB ports, and microphone/speaker ports. Hardware ports may be physically male or female. Different ports are physically identifiable by their different size of pins, shapes etc.

Hardware PORTS are available for:

• Mouse
• Keyboard
• Monitor
• Network
• Modem
• Audio ports
• Serial port,
• Parallel port
• USB port.

INPUT DEVICES

A computer would be useless without input devices. Input data is provided through input devices, such as keyboard, mouse. Input can also be provided by scanning images, voice recording, video recording etc. All input devices must translate the input into a form that is understandable by the computer i.e., machine readable form (binary or machine language). Some popular input devices are listed below.

• Keyboard
• Mouse
• Scanner
• Microphone
• CD-ROM
• Joystick

According to the way of input, input devices are categorized as shown below:

Common input device: Keyboard

Pointing input devices: Mouse, Trackball, Joystick, Light Pen, Touch screen

Audio input devices: Microphone, Sound card, Speech recognition system

Video input device: Video camera, Digital camera

Optical input devices: Scanner, OCR Optical Character Recognition), MICR (Magnetic Ink Character recognition), OMR (Optical Mark Recognition), Barcode reader

Brief description of some input devices are provided below:

Keyboard: common input device

The design of keyboard is similar to a standard type writer. Standard keyboard contains 101 Keys. Some keyboards have 110 keys, where extra keys are designed to work with windows OS.

Keyboard has 5 sections:

Typing keys (1,2,3,….., A, B, C, …..etc)

Numeric keypad (numeric keys on the right side)

Function Keys (F1, F2,…F12.on top)

Control Keys (ctrl, alt etc….)

Special Purpose Keys (Enter, Shift, Spacebar etc….)

When a key is pressed, keyboard interacts with a keyboard controller & keyboard buffer. Keyboard controller is a hardware, which connects keyboard to motherboard. Keyboard controller stores the code of pressed key in keyboard buffer and informs the computer software that an action has happened on the keyboard. The computer software checks and reads the keyboard buffer and passes the code of the pressed character to the system software.

Mouse: common pointing devices

Here input data is not typed. Data is entered by pointing the mouse to a location on the computer screen. Mouse may also be used to position the cursor on the screen, move an object by dragging, select object by clicking. Cursor can be positioned at any location on the screen by simply moving the mouse. Various operations that can be performed with Mouse device are:

• Pointing
• Left click
• Right click
• Drag & drop

OUTPUT DEVICES

A computer interacts with the external environment via I/O devices attached to it. Input device is used for providing data and instructions to the computer. After processing the input data, computer provides output to the user via output device. I/O devices that are connected to the computer machine are also called peripheral devices.

Some popular output devices are listed below:

• Monitor
• Speakers
• Headphones
• Printer – Dot Matrix, Ink Jet, Laser

INPUT/OUTPUT DEVICES

Some devices function as both input and output devices. These I/O devices provide input to computer as well as get output from computer. Hard disk drive, USB drive, Floppy disk drive, CD drive, DVD drive are examples of devices, which can be used for inputting and outputting purpose.