Saturday, 5 September 2015




Computer is an integration of hardware and software which can accept, process and generate output for further use by the user. In simple term, computer is just a simple processing device.

In order to process a input by computer, there are numbers of hardware is required to convert the input in the user readable format because computer only understand binary language that is 0 and 1. Here 0 means low and 1 means High.

Logically, the meaning of computer is "a machine who can calculate/ compute".  Either you use computer to calculate numbers or do computing while browsing internet and using applications to satisfy once need.

Lets discuss the major components which makes the computer as a system:

  1. Motherboard:- Motherboard is like a heart of the computer which enable the communication interface between all connected hardware like CPU, RAM, Mouse, Keyboard, Hard Disk, Printer, Scanner, Camera, VDU etc. It creates an communication interface between input devices with CPU and with Output devices to show results.
  2. Central Processing Unit(CPU):- CPU is like a brain of the computer which interprets the input command and based on the processing desire, it transform the input command into output. Whatever we see / listen on the desktop which includes icons, folders, graphics, pictures, movies / websites / music etc. are being processed by CPU only. When we talk about application software, these are just a set of instructions only written in high level language and we install to use it. Please understand all software are only language which we cannot use without CPU, because when we give a command to use browser to surf Internet, browser is a collection of files of various set of instructions written in High Level Language, which our CPU processes and transform them into user understandable format.CPU has 3 units namely, Control Unit , Logical and Arithmetic Unit. Control unit is like a manager of CPU who control the flow of instructions to be processed and directs them either to logical unit or arithmetic unit on the basis of types of instructions.
  3. Random Access Memory(RAM):- RAM is knowns as primary memory of computer system which is also a temporary memory. Lets understand why RAM is called a primary memory. As I already explained about software that is only a collection of files of various sets of instruction written in High Level Language which CPU processes in user readable format, that how machine interacts with humans. RAM provides a space to computer system where these files of specific software can be loaded, so that CPU can do his action of transforming these numbers of files into user readable format. Even Operating system is also a software who also require space in RAM, for further processing by CPU. Now lets understand why RAM is known as Temporary memory, with the help of above explanation, when a user wants to use computer, he gives wake up command by pressing power button, once it is done, OS gets loaded into RAM and CPU starts processing these OS files and the user see the booting up of OS. Once OS is ready, we may give command to start MS-WORD or any other software, since MS-WORD is an application software combination of various sets of instructions, these files gets loaded into RAM and CPU processes. When we give command to close MS-WORD, all those files which required to be processed by CPU, gets off-loaded from RAM. When we give shut down command, whatever applications are open, will be erased from RAM. That is why we call it a temporary memory which is volatile in nature- reads and write multiple times.
  4. Hard Disk (HDD):- HDD is known as secondary device of computer which is used to store data permanently. Here permanently means, whatever software we install, music/video files we save, that stores in HDD and it will remain there until we wish to delete them. HDD plays a very important role in the performance of a computer system because whatever applications we wish to open , any files we wish to view/ use, system loads these files into RAM from HDD only. If HDD read and write speed is slow, then the files will take time to get loaded in RAM, if files are not loaded fully, CPU will not initiate the process, and ultimately user needs to wait for the output to come. And if read and write speed of HDD is high, you can imagine, read and write of data files will be faster and user will get response immediately. That is how we measure the performance of the computer system. Normally there are two types of HDD available with 5200RPM and 7200RPM. Some of the manufacturers are using SSD (Solid State Drive) whose read/write speed is 3 times faster than the normal HDD.
  5. Read Only Memory (BIOS CHIP):- ROM is permanent memory and once data is stored, it is very difficult to delete it. It is also depends upon which types of ROM you are using in the system. BIOS is knows as Basic Input Output System, this is the ROM chip integrated in the motherboard in which few instructions are stored who checks and confirms the availability of primary hardware and software to start the machine. When we switch on the computer, first command will reach to BIOS chip and whatever instructions are stored will get executed automatically. After confirming the required hardware, it instruct the computer to load the Operating system files from HDD into RAM, that process of loading OS files into RAM is  called booting up. In case of any hardware failure which is required and written as instruction in BIOS chip, BIOS inform the user accordingly, so that corrective actions can be initiated by the user or engineer.
The above are the components which are essential to set up processing environment which has to be complemented by Input devices and Output devices.

Input Devices are used to give user instructions to computer whereas output devices are used to show the processed output by the computer.

Input Device includes, Keyboard ,Mouse, Camera, Mic and Scanner etc whereas LCD, printers and speakers are knows as Output device.