CLASSIFICATION OF COMPUTER:
The digital computers
that are available nowadays vary in their sizes and types. The computers are
broadly classified into four categories based on their size and type:
1)
Microcomputers,
2)
Minicomputers,
3)
Mainframe
computers, and
4)
Supercomputer.
Fig: Classification of Computers
Microcomputers:
Microcomputers are
small, low-cost and single-user digital computer. They consist of CPU, input unit,
output unit, storage unit and the software. Although microcomputers are
stand-alone machines, they can be connected together to create a network of
computers that can serve more than one user. IBM PC based on Pentium
microprocessor and Apple Macintosh are some examples of microcomputers.
Microcomputers
include desktop computers, notebook computers or laptop, tablet computer,
handheld computer, smart phones and netbooks.
Fig: Microcomputers
Desktop Computer or
Personal Computer (PC) is the most common type of microcomputer. It is a
stand-alone machine that can be placed on the desk. Externally, it consists of
three units-keyboard, monitor, and a system unit containing the CPU, memory,
hard disk drive, etc. It is not very expensive and is suited to the needs of a
single user at home, small business units, and organizations. Apple, Microsoft,
HP, Dell and Lenovo are some of the PC manufacturers.
Notebook Computers or
Laptop resembles
a notebook. They are portable and have all the features of a desktop computer.
The advantage of the laptop is that it is small in size (can be put inside a
briefcase), can be carried anywhere, has a battery backup and has all the
functionality of the desktop. Laptops can be placed on the lap while working (hence
the name). Laptops are costlier than the desktop machines.
Netbook are smaller notebooks
optimized for low weight and low cost, and are designed for accessing web-based
applications. Starting with the earliest netbook in late 2007, they have gained
significant popularity now. Netbooks deliver the performance needed to enjoy
popular activities like streaming videos or music, emailing, Web surfing or
instant messaging. The word netbook was created as a blend of Internet
and notebook.
Tablet Computer has features of the
notebook computer but it can accept input from a stylus or a pen instead of the
keyboard or mouse. It is a portable computer. Tablet computer are the new kind
of PCs.
Handheld Computer or
Personal Digital Assistant (PDA) is a small computer that can be held on the
top of the palm. It is small in size. Instead of the keyboard, PDA uses a pen
or a stylus for input. PDAs do not have a disk drive. They have a limited
memory and are less powerful. PDAs can be connected to the Internet via a wireless
connection. Casio and Apple are some of the manufacturers of PDA. Over the last
few years, PDAs have merged into mobile phones to create smart phones.
Smart Phones are cellular phones
that function both as a phone and as a small PC. They may use a stylus or a
pen, or may have a small keyboard. They can be connected to the Internet
wirelessly. They are used to access the electronic-mail, download music, play
games, etc. Blackberry, Apple, HTC, Nokia and LG are some of the manufacturers
of smart phones.
Minicomputers:
Minicomputers are
digital computers, generally used in multi-user systems. They have high
processing speed and high storage capacity than the microcomputers.
Minicomputers can support 4–200 users simultaneously. The users can access the
minicomputer through their PCs or terminal. They are used for real-time
applications in industries, research centers, etc. PDP 11, IBM (8000 series)
are some of the widely used minicomputers.
Fig: Minicomputer
Mainframe Computers:
Mainframe computers
are multi-user, multi-programming and high performance computers. They operate
at a very high speed, have very large storage capacity and can handle the
workload of many users. Mainframe computers are large and powerful systems
generally used in centralized databases. The user accesses the mainframe
computer via a terminal that may be a dumb terminal, an intelligent terminal or
a PC.
A dumb terminal cannot
store data or do processing of its own. It has the input and output device
only. An intelligent terminal has the input and output device, can do
processing, but, cannot store data of its own. The dumb and the intelligent
terminal use the processing power and the storage facility of the mainframe
computer.
Mainframe computers
are used in organizations like banks or companies, where many people require
frequent access to the same data. Some examples of mainframes are CDC 6600 and
IBM ES000 series.
Fig: Mainframe computer
Supercomputers:
Supercomputers are
the fastest and the most expensive machines. They have high processing speed
compared to other computers. The speed of a supercomputer is generally measured
in FLOPS (FLoating point Operations Per Second). Some of the faster supercomputers
can perform trillions of calculations per second. Supercomputers are built by
interconnecting thousands of processors that can work in parallel.
Supercomputers are used for highly calculation-intensive tasks, such as,
weather forecasting, climate research (global warming), molecular research,
biological research, nuclear research and aircraft design. They are also used
in major universities, military agencies and scientific research laboratories.
Some examples of
supercomputers are IBM Roadrunner, IBM Blue gene and Intel ASCI red. PARAM is a
series of supercomputer assembled in India by C-DAC (Center for Development of
Advanced Computing), in Pune. PARAM Padma is the latest machine in this series.
The peak computing power of PARAM Padma is 1 Tera FLOP (TFLOP).
Fig: Supercomputer
No comments:
Post a Comment