TYPES OF COMPUTERS
Computers can be classified based on their
principles of operation or on their configuration. By configuration, we mean
the size, speed of doing computation and storage capacity of a computer.
Types of Computers based on Principles of Operation
There are three different types of computers
according to the principles of operation. Those three types of computers are
- Analog Computers
- Digital Computers
- Hybrid Computers
Analog Computers
Analog Computer is a computing device that works
on continuous range of values. The results given by the analog computers will
only be approximate since they deal with quantities that vary continuously. It
generally deals with physical variables such as voltage, pressure, temperature,
speed, etc.
Digital Computers
On the other hand a digital computer operates on
digital data such as numbers. It uses binary number system in which there are
only two digits 0 and 1. Each one is called a bit.
The digital computer is designed using digital
circuits in which there are two levels for an input or output signal. These two
levels are known as logic 0 and logic 1. Digital Computers can give more
accurate and faster results.
Digital computer is well suited for solving
complex problems in engineering and technology. Hence digital computers have an
increasing use in the field of design, research and data processing.
Based on the purpose, Digital computers can be
further classified as,
- General Purpose Computers
- Special Purpose Computers
Special purpose computer is one that is built for
a specific application. General purpose computers are used for any type of
applications. They can store different programs and do the jobs as per the
instructions specified on those programs. Most of the computers that we see
today are general purpose computers.
Hybrid Computers
A hybrid computer combines the desirable features
of analog and digital computers. It is mostly used for automatic operations of
complicated physical processes and machines. Now-a-days analog-to-digital and
digital-to-analog converters are used for transforming the data into suitable
form for either type of computation.
For example, in hospital’s ICU, analog devices
might measure the patients temperature, blood pressure and other vital signs.
These measurements which are in analog might then be converted into numbers and
supplied to digital components in the system. These components are used to
monitor the patient’s vital sign and send signals if any abnormal readings are
detected. Hybrid computers are mainly used for specialized tasks.
Types of Computers based on Configuration
There are four different types of computers when
we classify them based on their performance and capacity. The four types are
- Super Computers
- Mainframe Computers
- Mini Computers
- Micro Computers
Super Computers
When we talk about types of computers, the first
type that comes to our mind would be Super computers. They are the best
in terms of processing capacity and also the most expensive
ones. These computers can process billions of instructions per second.
Normally, they will be used for applications which require intensive numerical
computations such as stock analysis, weather forecasting etc. Other uses of
supercomputers are scientific simulations, (animated) graphics, fluid dynamic calculations,
nuclear energy research, electronic design, and analysis of geological data
(e.g. in petrochemical prospecting). Perhaps the best known super computer
manufacturer is Cray Research. Some of the "traditional"
companies which produce super computers are Cray, IBM
and Hewlett-Packard.
As of July 2009, the IBM Roadrunner, located at
Los Alamos National Laboratory, is the fastest super computer in the world.
If you want to know more advanced details about super
computers, refer to SuperComputers
Mainframe Computers
Mainframe computers can also process data at very
high speeds vi.e., hundreds of million instructions per second and they are
also quite expensive. Normally, they are used in banking, airlines and railways
etc for their applications.
Mini Computers
Mini computers are lower to mainframe computers
in terms of speed and storage capacity. They are also less expensive than
mainframe computers. Some of the features of mainframes will not be available
in mini computers. Hence, their performance also will be less than that of
mainframes.
Micro Computers
The invention of microprocessor (single chip CPU) gave birth to the much cheaper micro computers. They are further classified into- Desktop Computers
- Laptop Computers
- Handheld Computers(PDAs)
Desktop Computers
Today the Desktop computers are the most popular computer systems.These desktop computers are also known as personal computers or simply PCs. They are usually easier to use and more affordable. They are normally intended for individual users for their word processing and other small application requirements.
Laptop Computers
Laptop computers are portable computers. They are lightweight computers with a thin screen. They are also called as notebook computers because of their small size. They can operate on batteries and hence are very popular with travellers. The screen folds down onto the keyboard when not in use.
HANDHELD COMPUTERS
Handheld computers or Personal Digital Assistants (PDAs) are pen-based and also battery-powered. They are small and can be carried anywhere. They use a pen like stylus and accept handwritten input directly on the screen. They are not as powerful as desktops or laptops but they are used for scheduling appointments, storing addresses and playing games. They have touch screens which we use with a finger or a stylus.
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