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Computer
Computer is an automatic, electronic machine that
Accept data & instructions from a user (INPUT)
Store the data & instructions (STORAGE)
Manipulate the data according to the instructions
(PROCESSING)
Store &/or output the results to the user
(OUTPUT)
DATA
Data in a computer terminology mean raw facts and
figures.
For ex-Mohan, 1977 etc.
INFORMATION
INFORMATION. It means what we get after processing
Data (meaningful
data); Data are aggregated and summarized in various meaningful ways to form
information for E.g. Mohan’s roll no is
1977.
TYPES OF COMPUTERS
Computers can be classified into three categories:-
1. Digital
computers
2. Analog
computers
3. Hybrid
computers
DIGITAL
COMPUTERS
The computers working upon binary digits are digital
computers.
They are accurate and fast.
They have become omnipresent recently.
CLASSIFICATION
OF DIGITAL COMPUTERS
These can be classified in two ways.
Purpose-wise
Size and performance wise
PURPOSE-WISE
On this basis
there are two divisions:--
- Special-purpose computers
- General purpose computers
SPECIAL
PURPOSE COMPUTERS
Those designed to perform a specific task.
The instructions are permanently scratched in the
system itself.
Though they are accurate they aren't versatile.
GENERAL
PURPOSE COMPUTERS
These are
versatile computers which we generally use. These don’t have permanent programs
(i.e. in memory) but many applications are available on many mediums like HD.
These are called at the time of execution.
SIZE AND PERFORMANCE WISE
Embedded computers
Micro computers
Mini computers
Mainframe computers
Super computers
Basic
Parts of Computer
• Hardware
–
Mechanical devices in the computer
–
Anything that can be touched
•
Software
–
Tell the computer what to do
–
Also called a program
–
Thousands of programs exist
Hardware
The term hardware refers to all of the physical
devices, or components, that a computer is made
Of A computer is not one single device, but a system
of devices that all work together. Like the
Different instruments in a symphony orchestra, each
device in a computer plays its own part.
A typical computer system consists of the following
major components:
• The central processing unit (CPU)
• Main memory
• Secondary storage devices
• Input devices
• Output devices
Input
Devices
Input basically means getting data into the computer
to be processed.
The most common input devices are Keyboard and
Mouse,
Output
Devices
Output basically means getting data out of the
computer.
Examples are
Monitor
Printer
Speakers
Storage
Devices
Storage devices are the one used to keep data that
has been processed so that data can be retrieved at a later time to be used
again.
Examples are:
Hard Disk
Floppy Disk
CD’s, DVD’s
Central
Processing Unit (CPU)
The main chip in the computer.
It is the heart of the computer and communicates
with the output, input and storage devices to perform tasks that are important
to the functioning of the computer.
Its main function is
- to process instructions
- manage the flow of information through the computer system.
- perform calculations.
CPU composed of two main components:
Control Unit
Arithmetic and Logic Unit (ALU)
SOFTWARE
Software represents the set of programs that governs
the operation of a computer system and make the hardware run. Software can be
classified broadly into three categories:--
Operating System
Language processors
(Operating
System &Language processors are collectively called as system software.)
Application software
LANGUAGE PROCESSORS
The system programs that perform the job of
converting codes in computer understandable language are known as language
processors.
The language processors are given below:-
Assembler .The language processor converts the
program written in assembly language to machine language.
Interpreter this language processor converts a HLL
program into machine language by converting and executing it line by line.
Compiler it also converts a HLL program into machine
language but a manner which is way different from an n assembler. It converts
the entire program in one go, and reports the errors of the program along with
line numbers.
A combination of compiler and assembler is best up
to the requirement.
APPLICATION SOFTWARE
Application software is the set of programs
necessary to carry out operations for a specified application.
Application software can further be subdivided into
two categories:
1. Customized application software. The type of
application which is tailor made software according to a user’s requirement.
2. General application software. The type of
software developed keeping in mind the general requirements for carrying out a
specific task. Many users can use it simultaneously as it fulfills the general
requirements.
STRENGTHS AND WEAKNESSES OF A COMPUTER
STRENGTHS
OF A COMPUTER
What has made the inevitable shift from manual style
of working to computerized working possible?
There must be some advantages of computer over the
previous. The strength of computers :-
Speed. Computers, much faster than human beings, can
execute millions of instructions in one second and thus can perform a task in
minute/s which if performed manually would eat days together.
High storage capacity. Computers can store a large
amount of information in a very small space.
Accuracy. Computers can perform all the calculations
and comparisons accurately provided the hardware doesn’t malfunction.
Reliability. Computers are immune to tiredness and
boredom or fatigue. Thus they are more reliable than human beings.
Versatility. Computers can perform repetitive jobs
efficiently. Along with it they can handle various tasks. They can work in
areas where human mind can err. They can work with various types of data for
ex—graphic, audio, visual, characters etc
WEAKNESSES
OF A COMPUTER
But the advantages counted limitations remain
because limitations must follow advantages.
Here limitations are:--
LACK OF DECISION MAKING POWER. Computers cannot
decide on their own. They lack the power which is a great asset to us and
everybody who is a human.
IQ ZERO. Computers are dumb machines with zero IQ.
They need to be told
