The Cyber Cops

Computer Hardware


A computer has two aspects – Hardware and Software.

Whatever you can touch in your computer is hardware. A monitor, a keyboard, a mouse, a speaker, everything is an example of a hardware.

We can describe hardware in three categories – input devices, processing devices, output devices.

Input Devices

This hardware takes input from the user to be used for further processing.



It is safe to assume that whoever has seen a computer has seen keyboard. A keyboard is the most basic input device of a modern computer. You can use a computer without a mouse, but the keyboard is an absolute necessity. A keyboard is basically a set of keys. You press a key and the equivalent input is sent to the computer. Almost all consumer keyboards are QWERTY keyboards (name based on the first five keys Q,W,E,R,T,Y). You will see the letters as the centre of a keyboard, then there are a row of numbers above that. You will notice function keys over that (F1, F2,F3….F11, F12). These function keys serve as shortcuts to specific tasks, or trigger specific actions. Apart from that there are several keys with specific actions.



A mouse is an integral part of a consumer desktop. The mouse was introduced to the user with the introduction of graphical user interface. A mouse is useless in a command line interface (CLI), but operating systems with graphical user interface (GUI) without a mouse is almost unimaginable. A mouse has three primary buttons – left click, scroll wheel, right click. There are also special mouse with several programmable buttons, but three button mouse is the most common one.



Microphones are used to give voice input. Voice commands, voice instructions are fed through mics.

Touch screen

Touch screen device

Touch screens are primary mode of input in tablets and smartphones. A touch screen uses virtual keyboard where users type, and touch itself replaces mouse. Nowadays many laptops come with a touch screen.

Optical Mark Reader

You may know optical mark reader as OMR. OMR sheets are used in various MCQ exams. The examinees mark boxes with pencils/pens. OMR projects light on an OMR sheet, where there is marked with pen/pencil, the light reflects brighter there, and the OMR detects that.

Optical Character Reader

OCR Photo

Optical character reader or OCR are like OMR, but advanced. OCR is used to read something written on paper using ink. When you go to update your bank pass book, and OCR reads the data and feed it to the machine.

Magnetic Ink Character Reader

Magnetic ink character reader or MICR is used to verify documents. MICR reads characters on documents written using magnetic ink, and verifies the authenticity of the document.

Magnetic Stripe Reader

Magnetic stripe reader or MSR is used to read data on your debit card or credit or any type of card where data is stored using magnetic stripes.

Barcode Reader

Bar code scanner photo

Barcode reader are using in shops or malls or in any place where information needs to be extracted from barcodes and QR codes.

Apart from these, there are punch card readers, light pen, etc.

Processing Unit

The processing unit, as explained before, calculated and performs any given task. The Central Processing Unit or CPU sits on the Motherboard, and the Motherboard connects all the different components of the hardware.

The CPU handles all the tasks and calculations, this is the brain of the computer. The CPU gets the instruction from the RAM, does the required calculations and send the results back. The CPU is a microchip. CPUs are generally air-cooled, or water cooled, but low powered CPUs (all mobile devices and certain laptops) use a fanless design because the power consumption is very low. Some CPU come with integrated GPU (Graphical Processing Unit).

The Chipset on the motherboard connects the CPU to other components such. The RAM (Random Access Memory) holds the data which is actively accessed by the CPU, to know more about RAM, click here.

The ROM (Read Only Memory) on the motherboard stores the BIOS (Basic Input Output System) which executes the first functions to run the computer. There is also a CMOS battery on the motherboard that powers the CMOS memory, which holds the date and time information.

The CPU connect to other components through Buses. For example, USB means Universal Serial Bus, that means you connect your pendrive or data cable through a Bus.

A computer also requires a GPU or Graphical processing unit. The GPU handles the graphical processing, as the name implies. GPUs are used to run intensive games, or processes that require graphical acceleration.

Output Devices

Output devices display the result of the task user gave to the computer. There are two types of outputs – Soft copy output and hard copy output.

Soft copy output means you cannot physically touch the output, you can only see or hear the output. Hard copy output means you can physically touch the output. Soft copy output devices are Display unit or monitor, and speakers. Hard copy output unit is printer.


Monitor photo

Visual outputs are displayed on the monitor. Old monitors used cathode ray tube technology, that is why those monitors were called CRT Monitors. CRT monitors were large in size and had a box like shape. Later LCD monitors gained popularity. LCD monitors are flat, and thinner than CRT monitors. LCD monitors use a LED backlit panel which emits light, and the panel in front of that displays colour. In recent years, OLED has gained popularity. OLED or Organic LED does not use a backlight to display, in an OLED panel, individual pixels can turn on or off, so the panel shows absolute black colour rather than a gray black, and more contrast. OLED displays are more common in TVs and Smartphones.


Speaker photo

Speakers deliver sound output.


Printer photo

Printers can print visual outputs on paper. A printer provides you with hard copy output. There are different types of printers that uses different technology to print as follows:

  • Laser Printer: Laser printer can print high quality texts and photographs. It uses a laser beam to print image.
  • Inkjet Printer: Inkjet printer propells ink droplets on paper to create the output. These types of printers are most common.
  • Dot-Matrix Printer: Dot-Matrix printer uses small pins to transfer ink onto the paper.
  • Drum Printer: Drum printer uses a cylinder, which is horizontally mounted, and uses a stamp like method to print.
  • Other than these, there are chain printers, dye-sublimation printers, thermal printers, solid ink printers, liquid in electrostatic printers etc. But laser printers and inkjet printers are most common nowadays.

For Wikipedia entry on Computer hardware, click here.

For more posts on Computer basics, click here.

For more posts in The Cyber Cops project, click here.


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