Introduction Of Computer System

Classification of computer

All modern computers and computing devices use microprocessors whose speeds and storage 
capacities are skyrocketing day by day. The developmental benchmark for computers is now 
their size. Computers are now classified on the basis of their use or size:

 Desktop
 Laptop
 Tablet
 Server
 Mainframe
 Supercomputer
Let us look at all these types of computers in detail.



Desktop

Desktop computers are personal computers (PCs) designed for use by an individual at a 
fixed location. IBM was the first computer to introduce and popularize use of desktops. A 
desktop unit typically has a CPU (Central Processing Unit), monitor, keyboard and mouse.
Introduction of desktops popularized use of computers among common people as it was 
compact and affordable.
The foremost design consideration here was 
user friendliness.



Laptop

Despite its huge popularity, desktops gave way to a more compact and portable personal 
computer called laptop in 2000s. Laptops are also called notebook computers or simply 
notebooks. 
Laptops run using batteries and connect to networks using Wi-Fi (Wireless 
Fidelity) chips. 
They also have chips for energy efficiency so that they can conserve power 
whenever possible and have a longer life. 
Modern laptops have enough processing power and storage capacity to be used for all office 
work, website designing, software development and even audio/video editing.


Tablet

After laptops computers were further miniaturized to develop machines that have processing 
power of a desktop but are small enough to be held in one’s palm. Tablets have touch sensitive 
screen of typically 5 to 10 inches where one finger is used to touch icons and invoke 
applications. 
Keyboard is also displayed virtually whenever required and used with touch strokes. 
Applications that run on tablets are called apps. They use operating systems by Microsoft 
(Windows 8 and later versions) or Google (Android). Apple computers have developed their 
own tablet called iPad which uses a proprietary OS called iOS



Server

Servers are computers with high processing speeds that provide one or more services to other 
systems on the network. 
They may or may not have screens attached to them. 
A group of

computers or digital devices connected together to share resources is called a network.
Servers have high processing powers and can handle multiple requests simultaneously. Most 
commonly found servers on networks include:
 File or storage server
 Game server
 Application server
 Database server
 Mail server
 Print server



Mainframe 

Mainframes are computers used by organizations like banks, airlines and railways to handle 
millions and trillions of online transactions per second. Important features of mainframes are:
 Big in size
 Hundreds times faster than servers, typically hundred megabytes per second
 Very expensive
 Use proprietary OS provided by the manufacturers

 In-built hardware, software and firmware security features


Supercomputer

Supercomputers are the fastest computers on Earth. They are used for carrying out 
complex, fast and time intensive calculations for scientific and engineering applications. 
Supercomputer speed or performance is measured in teraflops, i.e. 1012 floating point 
operations per second. 
Chinese supercomputer Sunway TaihuLight is the world’s fastest supercomputer with a 
rating of 93 petaflops per second, i.e. 93 quadrillion floating point operations per second.
Most common uses of supercomputers include:
 Molecular mapping and research
 Weather forecasting
 Environmental research

 Oil and gas exploration