types of computers

Computer is an electronic device that reads and processes data to from
an information. Computer helps us to solve our problems. On the basis
of size and computation power, the computer is categorized into 4
types;

Super computer: they are fastest computers. This computer is used in
research and other operations where there is huge numerical
calculation.

Mainframe computers: These computers have many terminals. So they are
used in big business organizations where they are many departments and
people.


Mini computers: these computers are smaller than mainframes but bigger
then personal computer. They are useful for moderate organizations.

Micro computers: These computers are also knows as personal computers
(pc) .They is used for personal and office purposes.




There are four basic functions performed by computers:

1. Input 2.Prossing
3. Output 4.Storage

These functions are diagrammatically represented as:




Data i
information



Input: it is performed by input devices such as keyboard, mouse,
microphone, scanner etc.

Processing: Central Processing Unit (CPU). Processor.

Output: it is done by output devices such as monitor, printer and speaker.


Storage: it is performed by storage devices such as RAM ,hard disk
optical disks etc.
Hardware and software:

Computer system is generally divided into two parts:
Hardware: hardware refers to the physical parts of the computer like
CPU, monitor, printer etc. which can be touched and felt.

Software: software is a group of programs which make computers work.
The software tells the computer what to do and how to do.
The software is further divided into three major groups:

a. Application software: it is a group programs designed to solve
particular problem example word processing, spreadsheet, multimedia
and presentation, database etc.

b. System software: it is setup of programs which helps user to
communicate with hardware example operating system, assembler,
complier, interpreter etc.

c. Utility software: it provides service for developing and debugging
computer programs example Norton utilities, pc tools etc.



Computer Memory

The memory is the storage space in the computer system. It is the
capacity of computer to store data and information. There are two
types of memory: primary and secondary.

Primary memory
It is also called internal or main memory.RAM and ROM are the types of
primary memory.

RAM: RAM stands for random access memory. it most commonly used
memory. But, it is volatile memory. so it need regular supply of power
to hold its content.

ROM: ROM stand for read only memory. It is only for reading. It is the
permanent memory. So it holds the data even after the computer is
switched off.
Secondary memory
The secondary memory is used to store data and information for later
use. They are also called Mass storage or Auxiliary Memory because
they can store huge data and information for longer duration of time.
Secondary memory is installed in the computer from magnetic disks
such as Hard disk, Floppy disk etc. optical Disks such as CD _ROM
DVDs, etc or electronic storage like pen drive.
Hard disk and floppy disk
Hard disk and floppy disk are the most popular
magnetic disks. They are used to store huge volume of data. Hard disk
s store data and programs permanently. Floppy disks are commonly used
for copying files between computers, loading small programs into
computer etc.
Comparatively, floppy disks have lower storage capacity
than hard disks but they are cheap and easy to handle. Due to the
robust features and easy of use, the Pen-drive has higher capacity
storage device than floppy.

Magnetic Tapes
Magnetic tape is similar to commonly used audio tape recorder. It is
used for backing up the information as it is cheap and has high
storage capacity.

CD-ROM
CD-ROM stands for Compact Disk Read Only Memory. It is an optical
disk. It can store 500 to 800MB of data. Once the data is stored in
the CD-ROM, it cannot be changed.

DVD
Digital versatile disks are similar to CD-ROM in
its look. But it is featured with high data capacity. They can store
twice and something thrice the data than CD-ROM can store. The data
Preservance and quality of data stored are higher in DVDs than CD-ROM.

Computer language
Computer language are the language that con be understood by the
computers. It consists of strict rules and patterns. Basically,
computer languages are categorized into two types:

Low-level languages:-
Low level languages are machine oriented languages. They are easily
understood by computers but it is difficult for people to understand
them. Machine language and Assembly language are low level languages.
High-Level languages:-
High level languages are easy to use. These
languages are close to human language. They use English words and
English like statements which make them easier to learn and program
written in high level language must be converted to machine level
language, before it is used by computers. Some of the popular high
level languages are BASIC, FOTRAN, PASCAL, LISP, C, C++, java etc.
Advantages of computer
Computers have several advantages. Some of them are listed as follows:
a. Computer can perform complex operation in a short time
b. Computer can process large volumes of data.
c. Computers can reliable i.e they can work continuously for long time.
d. Computers are accurate i.e computer do not make mistakes.
e. Computers are versatile i.e a single computer can do a variety of
jobs such plating music, displaying movies, internet connection etc.
Application of computer
Nowadays, computers are used in every area. All the technological
advancement that we see today are due to the computer. The common
application areas of computers are:
a. Education
b. Business
c. Medicine and Healthcare
d. Communication
e. Space technology etc.