Basics of Computer and its Operations

Computer is a device that transforms data into meaningful information. It processes the input according to the set of instructions provided to it by the user and gives the desired output quickly. A Computer can perform the following set of functions:

Accept data
Store data
Process data as desired
Retrieve the stored data as and when required
Print the result in desired format.

Data and Information:

Data: It is the term used for raw facts and figures fed into the computer and along with the set of instructions which enables the computer to convert this raw data into the refined and useful information.

Information: Data represented in useful and meaningful form is information.

Classification of Computers:
Computers can be classified based on the technology being used and the way they are designed to perform the various tasks. Computers can be categorized into Digital, Analog and Hybrid based on their design and working:

Digital Computers : These are the modern computers which are capable of processing information in discrete form. In digital technology data which can be in the form of letters, symbols or numbers is represented in binary form i.e. 0s and 1s. The digital computers are used in industrial, business and scientific applications. They are quite suitable for large volume data processing.
Analog Computers : These computers are used to process data generated by ongoing physical processes. A thermometer is an example of an analog computer since it measures the change in mercury level continuously. Analog computers are well suited to simulating systems. A simulator helps to conduct experiments repeatedly in real time environment. Some of the common examples are simulations in aircrafts, nuclear power plants, hydraulic and electronic networks.
Hybrid Computers : These use both analog and digital technology. It has the speed of analog computer and the accuracy of a digital computer. It may accept digital or analog signals but an extensive conversion of data from digital to analog and analog to digital has to be done. Hybrid Computers are used as a cost effective means for complex simulations.

Classification of Digital Computers

Micro Computers :These are also known as Personal Computers. These type of digital computer uses a microprocessor (a CPU on a single chip) and include both desktops and laptops. These computers can work on small volume of data, are very versatile and can handle variety of applications. These computers are being used as work stations, CAD, multimedia and advertising applications.
Example: portable computers such as PDAs (Personal Digital Assistants) and tablets

Mini Computers :These computers can support multiple users working simultaneously on the same machine. These are mainly used in an organization where computers installed in various departments are interconnected. These computers are useful for small business organizations.

Main Frames : These computers are large and very powerful computers with very high memory capacity. These can process huge databases such as census at extremely fast rate. They are suitable for big organizations, banks, industries etc. and can support hundreds of users simultaneously on the network.

Super Computers : These are fastest and very expensive computers. They can execute billions of instructions per second. These are multiprocessor, parallel systems suitable for specialized complex scientific applications involving huge amounts of mathematical applications such as weather forecasting.

Peripheral Devices

These devices are used for performing the specific functions and are connected to the computer externally. These peripheral devices enable the computer to operate according to the user requirements by feeding data in and out of the computer. Peripheral devices are as follows:

INPUT DEVICES :

Keyboard
Mouse
Light Pen
Optical/magnetic Scanner
Touch Screen
Microphone for voice as input
Track Ball

OUTPUT DEVICES :These devices return processed data that is information, back to the user. Some of the commonly used output devices are:

Monitor (Visual Display Unit)
Printers
Plotter
Speakers

Difference between RAM and Hard-disk

RAM	Hard Disk
RAM is an electronic device	Hard-disk is an electromechanical device
Electronic device are faster in speed	Electro-mechanical device has speed slower than Electronic device.
CPU is an electronic device,so it’s speed can match with RAM.Therefore,CPU and RAM have connections and that connections is known as buses	Hard disk is an electro-mechanical device.Therefore,it’s speed cannot be match by CPU and hence their is no connection between hard-disk and CPU.

CPU process the data, and to process that data we need fast speed memory which is known as RAM.

Types of Software

System Software : These are those software,without which our PC,laptop won’t run, i.e it is must for a device to be operating.
For Example: Linux,Unix,Windows,etc.
Application Software : These are those software,without which our PC,laptop can run, i.e these software are not necessary for a device to be operating.
For Example: Facebook,What’s App,Games.

NOTE: In Earlier times i.e before 1970s,for making both these software we have to learn different languages.
For Example, Assembly language was used for System Software whereas Pascal,Cubel,etc. were used for making Application Software.

Difference between Hacker and Cracker

Hacker : They will just warn you something about malicious activity going around in your computer.It will not steal your information.
Cracker : They will try to steal your Information without informing you.

My Personal Notes

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