Computer is automatic problem-solving machine whose main
purpose is data processing or processing information and which is represented
The Latin word computer in the original sense means to
count. In that sense Computer means calculating device. Although computers have
been invented as computing devices, modern computers are not limited to just
counting. Computers are now being used in everything from research to household
information on the computer
The computer itself can do nothing. He does that by
instructing the computer in the right way. And we use the keyboard and mouse
attached to the computer to give instructions.
From the outside of a computer, we see four things. E.g.
(1) Keyboard This is an input device. With the help of this
we can give information to the computer by typing
(2) Mouse This is an input device. This allows us to direct
information to the computer.
(3) The CPU processes the information given to the computer
in this section. The English meanings are- C = Central, P = Processing, U =
Unit together Central Processing Unit Central processing area in Bengal.
(4) Monitor It is an output device. This section displays
The workings of a computer can be roughly divided into two
(1) Input unit – instruction receiving area. Keyboard and
mouse fall into this area.
(2) Output Unit- Output display area CPU and monitor within
The function of the input device is to communicate with the
computer. Any type of data is converted into binary electronics signals (Zero
and One) and sent to the CPU. Because the CPU cannot understand anything other
than this (0, 1).
The electronics signals coming from the input device are
transformed into human perceptible image based, alphabet based, math based,
word and picture based etc.
What does a computer
Computers basically do four important things. E.g.,
(1) It receives numbers or words and instructions from the
(2) processes data through instruction.
(3) transmits the results to the output device.
(4) Stores data as required and retrieves it from memory.
Types of computers-
Computers are mainly divided into 3 parts. E.g.
(1) Digital computer, (2) Analog computer, (3) Hybrid
Digital computer has again been divided into 4 parts. E.g.
(1) Super Computer, (2) Main Frame Computer, (3) Mini
Computer, (4) Micro Computer.
Different parts of
(1) CPU (2) Monitor (3) Keyboard (4) Mouse (5) Mousepad (6)
Printer (6) Disk (6) Speaker (9) Modem (10) Scanner etc.
There are 84 to 101 keys on the keyboard or 102 keys on some
keyboards. The keyboard can be roughly divided into 5 sections based on usage.
(1) Function key.
(2) Arrow keys.
(3) Alpha batik key.
(4) Numeric key or logical key.
(5) Special key.
The keys from F1 to F12 on the top left side of the key
board are called function keys. What is called a function because a specific
task can be done. This key is used to help with a program, or to run a program.
@ The arrow keys have four separate keys on the bottom right
of the keyboard. Some keys are also on the top of the board. The keys are
marked with an arrow. Which makes it easy to move the cursor right, left, up
and down. These are also called edit keys. Because these keys are also used for
The part of the Alpha Batik Key-Key Board where the letters
of the English alphabet from A to Z are arranged is called the Alphabetic
@ Numeric key or logical key
The keys that are numbered from 0 to 9 on the right side of
the keyboard are called numeric keys. There are arithmetic operators like +, -,
*, /. Also <,>, = logical operators are on the keyboard.
@ Special key
Apart from the mentioned keys, other keys on the keyboard
are called special keys because they perform certain functions. Below is a
description of the properties of the special keys.
@ Esc: This key is used to cancel any instruction.
@ Tab: This key is used to prepare paragraphs, columns,
numbers, starting paragraphs, etc. on the screen as required.
@ Caps Lock: This key is used to type English lowercase and
@ Shift: This key is used to type upper and lower case in
the same word or at the beginning. For example, to write two words, Dhaka,
Khulna, first press the shift key and then release the next key. This key is used
for typing in Bengali or the alphabet and for typing the text above and below
the format key. The computer is also given various commands by pressing the
function key along with the shift key.
@ Ctrl: The command is given by pressing a special key together
with this key. For the convenience of the user, there are two keys on the right
and left side of the keyboard.
@ Alt: This key is used in different ways to give different
commands in different programs and different commands can be created.
@ Enter: This key is used to execute instructions to the
computer. This key is also used to create new paragraphs for writing.
@ Pause Break: Any law on the computer