INTRODUCTION OF COMPUTER

                         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:--

1. Special-purpose computers
2. 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