Friday, July 16, 2010
Programming language and its type:
The computers software is to be written in a certain languages that they understand. The earlier computers were programmed in machine language or in numeric form but it were a bit harder to write in this language. After this many languages were developed for the smooth and easy working. There are mainly two types of languages:
a. High level language
b. Low level language
It has two types:
Machine language
Assembly language
High level language:
A programming language such as C, FORTRAN, PASCAL etc that enables programmer to write programs that are more or less independent particular type of computer. Such languages are considered as high level language. The main advantage of high level language over low level language is that they are easier to read, write and maintain. Ultimately programs written in high level language must be translated into machine language by a compiler.
Low level language:
Machine language:
It is a collection of binary digits or bits that computer reads and interprets. Machine language is the only language a computer is capable of understanding. Elemental language of computers, consisting of strings 0’s and 1’s. because machine language is the lowest level computer language and the only language that computer directly understands, a program written in more sophisticated language (c, PASCAL) or any other language must be converted to machine language prior to execution.
Assembly language:
It is a low level programming language using the human readable instruction on the CPU. It runs slower machine language entirely consist of numbers and are almost impossible for human to read and write. Assembly languages have the same structure to that at machine language but they enable a programmer to use names instead of numbers.
Each types of CPU have its own type of assembly language, programs written for one type of CPU does not run on other type. In early days all programs were written in assembly language but today its written in high level language.
Example:
Start
Mov sa #10
Mov s #3
Add = sa s, a; a = sa + s
` Stop
But assembly language understands the above language as:
Open
Stop
a. High level language
b. Low level language
It has two types:
Machine language
Assembly language
High level language:
A programming language such as C, FORTRAN, PASCAL etc that enables programmer to write programs that are more or less independent particular type of computer. Such languages are considered as high level language. The main advantage of high level language over low level language is that they are easier to read, write and maintain. Ultimately programs written in high level language must be translated into machine language by a compiler.
Low level language:
Machine language:
It is a collection of binary digits or bits that computer reads and interprets. Machine language is the only language a computer is capable of understanding. Elemental language of computers, consisting of strings 0’s and 1’s. because machine language is the lowest level computer language and the only language that computer directly understands, a program written in more sophisticated language (c, PASCAL) or any other language must be converted to machine language prior to execution.
Assembly language:
It is a low level programming language using the human readable instruction on the CPU. It runs slower machine language entirely consist of numbers and are almost impossible for human to read and write. Assembly languages have the same structure to that at machine language but they enable a programmer to use names instead of numbers.
Each types of CPU have its own type of assembly language, programs written for one type of CPU does not run on other type. In early days all programs were written in assembly language but today its written in high level language.
Example:
Start
Mov sa #10
Mov s #3
Add = sa s, a; a = sa + s
` Stop
But assembly language understands the above language as:
Open
Stop
Operating system:
Operating system (OS) is system software that helps the user to operate the computer and manage its resources. The primary purpose of the OS is to act as an interface between the computer and the user. As computer is a digital device which understands and works only in binary languages (also known as machine language that a computer understands) made of 0’s and 1’s only. It is impossible for a common people to work through or under the binary language. Hence, OS acts as an interface between user and computers. It makes the user to work with computer very easy like copy, type, print etc can be done very easily due to OS.
Without OS a computer can’t be used or it can’t be operated. OS manages all the resources of the computer i.e. CPU, memory, and input output devices. Operating system also helps other application to run in the computer very easily. Operating system creates working environment between user and the computer. OS can be said as the sole of the computer without which a computer can not work or be operated.
Some commonly used OS are MS-DOS, windows 98, Windows 2000, Windows XP and its series, Linux, vista etc.
Without OS a computer can’t be used or it can’t be operated. OS manages all the resources of the computer i.e. CPU, memory, and input output devices. Operating system also helps other application to run in the computer very easily. Operating system creates working environment between user and the computer. OS can be said as the sole of the computer without which a computer can not work or be operated.
Some commonly used OS are MS-DOS, windows 98, Windows 2000, Windows XP and its series, Linux, vista etc.
Computer software:
The finite set of instruction that the computer follows to solve a particular problem is called a computer program. Some programs called the system programs, direct the internal operation of the computer. This includes those, which control the input and output devices or manage the storage areas with in the computer. On the other hand, other programs called application program direct the computer to solve the specific user-oriented problems such as preparing report, accounting package and many more such application. Collectively the group of programs that a computer needs to function is known as computer software. The major components of system program include operating system, compiler and assembler and utility programs.
An operating system is the software that allows a computer hardware and software to work together. It is a layer of software between the user and the computer which provides the native environment .It consists of a programs and routines that coordinates processes, translate data from input from output devices, regulates data storage in memory, and allocated tasks to different processors. It also provides programs and function that help programmers develop new software. An operating system provides two related function: a standard programming environment for software developer and a standard working environment for users.
Compilers and assemblers are used to translate the program written in human understandable language, like FORTRAN into object module, which is used by linker to make an executable file. An executable file is then ready to be used by the users.
The systems of programs are a generally obtained from either the hardware vendor or independent software vendors. The applications programs may be written by any software developer according to the needs of the costumer. Every kinds of software can be developed as according to the want of the needers.
Generally some well developed and most useable business software’s are MS-WORD, MS-EXCEL, MS-POWERPOINT etc and many more like this.
An operating system is the software that allows a computer hardware and software to work together. It is a layer of software between the user and the computer which provides the native environment .It consists of a programs and routines that coordinates processes, translate data from input from output devices, regulates data storage in memory, and allocated tasks to different processors. It also provides programs and function that help programmers develop new software. An operating system provides two related function: a standard programming environment for software developer and a standard working environment for users.
Compilers and assemblers are used to translate the program written in human understandable language, like FORTRAN into object module, which is used by linker to make an executable file. An executable file is then ready to be used by the users.
The systems of programs are a generally obtained from either the hardware vendor or independent software vendors. The applications programs may be written by any software developer according to the needs of the costumer. Every kinds of software can be developed as according to the want of the needers.
Generally some well developed and most useable business software’s are MS-WORD, MS-EXCEL, MS-POWERPOINT etc and many more like this.
Computer hardware:
Simply the seen or touchable parts of a computer are known as hardware. The primary components are the input/output devices, memory units and processing elements. These processing and memory come inside the CPU (central processing unit).
Input unit:
Data and information are entered into a computer through input device. An input device converts the user input into a machine code that is understandable by a computer. Most commonly used input device is keyboard. Some other input devices are:
1. Punch card reader.
2. Paper tapes reader.
3. Magnetic tape reader.
4. Magnetic disk reader.
5. keyboard
6. mouse
7. Joy stick etc.
Central processing unit (CPU):
Central processing units (CPU) consist of the control and arithmetic units, memory and storage units. The CPU is, thus, the nerve centre of the computer system where actual computing process takes place. The CPU may be obtained in a number of configurations differing in speed and size of memory it works with. The control unit of CPU supervises all other units of the computer. It fetches the proper computer instructions from the memory unit and routes data, referenced by the instructions from the memory unit to the arithmetic unit and back to the memory unit. The arithmetic unit is where the arithmetic and logical operations are perfumed. The memory unit of the CPU stores data and program during processing. The size of the computer is generally depends on the number of storage locations in its memory. Storage locations are always multiple of the number 1024. it is also known as the brain of the computer as it performs over all functioning of the computer as the human brain does.
.
Output unit:
The output devices receive results and other processed information from the computer and provide them to users. The computer sends information to an output device in the binary form. An output device converts it into a suitable from convenient to users. VDU, printers etc. are example of output devices. Some commonly used output units are:
1. punches card
2. paper tape punches
3. printers
4. plotters
5. cathode Ray Tube displays
6. magnetic disk units
7. magnetic drum units
8. magnetic tape units
9. CD disk
10. speakers
11. Monitor
Input unit:
Data and information are entered into a computer through input device. An input device converts the user input into a machine code that is understandable by a computer. Most commonly used input device is keyboard. Some other input devices are:
1. Punch card reader.
2. Paper tapes reader.
3. Magnetic tape reader.
4. Magnetic disk reader.
5. keyboard
6. mouse
7. Joy stick etc.
Central processing unit (CPU):
Central processing units (CPU) consist of the control and arithmetic units, memory and storage units. The CPU is, thus, the nerve centre of the computer system where actual computing process takes place. The CPU may be obtained in a number of configurations differing in speed and size of memory it works with. The control unit of CPU supervises all other units of the computer. It fetches the proper computer instructions from the memory unit and routes data, referenced by the instructions from the memory unit to the arithmetic unit and back to the memory unit. The arithmetic unit is where the arithmetic and logical operations are perfumed. The memory unit of the CPU stores data and program during processing. The size of the computer is generally depends on the number of storage locations in its memory. Storage locations are always multiple of the number 1024. it is also known as the brain of the computer as it performs over all functioning of the computer as the human brain does.
.
Output unit:
The output devices receive results and other processed information from the computer and provide them to users. The computer sends information to an output device in the binary form. An output device converts it into a suitable from convenient to users. VDU, printers etc. are example of output devices. Some commonly used output units are:
1. punches card
2. paper tape punches
3. printers
4. plotters
5. cathode Ray Tube displays
6. magnetic disk units
7. magnetic drum units
8. magnetic tape units
9. CD disk
10. speakers
11. Monitor
Classification of computers:
On the basis of working mode:
Analog computer
Digital computer
Hybrid computer
Analog computer:
An analog computer is one that measures physical values such as temperature, pressure, humidity etc. The analog computer accepts processes and generates continuous data. One major use of analog computers has been as control device on a real time scale, for example the navigation of controlled rockets or factory automation.
Some examples: mechanical integrator, MONIAC computer, analog speedometer of bikes and car etc.
Digital computers:
A digital computer accepts processes and produces discrete data. It uses 0’s and 1’s for processing any information. They are extremely popular science they are faster and more accurate in calculation than analog computer. Modern digital computers find extensive use in scientific, business, administration and engineering applications, industrial application, airline railway reservation, education, medicine and many more.
Hybrid computers:
Hybrid computers are those computers which combine analog and digital capabilities in a single computer. Hybrid computers are used for some special application. It is the combination of both analog and digital computers. The digital component normally serves as the controller and provides logical operation, while the analog component normally serves as a solver of differential equation.
Example: HRS-100
On the basis of size:
Micro-computer:
Generally a computer that resides in user’s desktop is called a micro computer. Micro computer include PC’s, laptops, notebooks and handheld computers or palmtop computers. Example desktop PC, laptop etc.
Mini computer :
These computers are larger then micro computers and these computers are 3-25 times faster then micro computers. Example: prime 9755, vax 36 etc
Mainframe computer:
These computers are larger then mini computers and there processing speed is 10-100 times faster then micro computers. Example: IBM 1401, ICL 2950/10 etc.
Super computer:
These computers are larger in size and are most powerful computers and can process at a speed of several hundreds or even thousands of millions of instruction per second. Example: NEC 500, cray-xmp-14 etc.
Analog computer
Digital computer
Hybrid computer
Analog computer:
An analog computer is one that measures physical values such as temperature, pressure, humidity etc. The analog computer accepts processes and generates continuous data. One major use of analog computers has been as control device on a real time scale, for example the navigation of controlled rockets or factory automation.
Some examples: mechanical integrator, MONIAC computer, analog speedometer of bikes and car etc.
Digital computers:
A digital computer accepts processes and produces discrete data. It uses 0’s and 1’s for processing any information. They are extremely popular science they are faster and more accurate in calculation than analog computer. Modern digital computers find extensive use in scientific, business, administration and engineering applications, industrial application, airline railway reservation, education, medicine and many more.
Hybrid computers:
Hybrid computers are those computers which combine analog and digital capabilities in a single computer. Hybrid computers are used for some special application. It is the combination of both analog and digital computers. The digital component normally serves as the controller and provides logical operation, while the analog component normally serves as a solver of differential equation.
Example: HRS-100
On the basis of size:
Micro-computer:
Generally a computer that resides in user’s desktop is called a micro computer. Micro computer include PC’s, laptops, notebooks and handheld computers or palmtop computers. Example desktop PC, laptop etc.
Mini computer :
These computers are larger then micro computers and these computers are 3-25 times faster then micro computers. Example: prime 9755, vax 36 etc
Mainframe computer:
These computers are larger then mini computers and there processing speed is 10-100 times faster then micro computers. Example: IBM 1401, ICL 2950/10 etc.
Super computer:
These computers are larger in size and are most powerful computers and can process at a speed of several hundreds or even thousands of millions of instruction per second. Example: NEC 500, cray-xmp-14 etc.
Generation of computers:
A generation of computer refers to the state of improvement in the development of computer science and its technology. In terms of technology and used system computer has been divided into five generation. It is classified on the basis of size, its power, its reliability, processing speed, used memory, acceptable application and many more.
First generation of computer (1945-1956) :( Vacuum tubes)
The main features of first generation computer are listed below:
• It used vacuum tube as electronic circuit.
• The magnetic drums were used as primary storage and punch cards were used as secondary device.
• They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctioning.
• First generation of computers fully depends upon machine language to perform operations, and they could only solve one problem at a time.
• Operating speed was used in terms of millisecond. Every CPU has its own unique machine language. Programs must be rewritten or recompiled, therefore to run in different types of computer.
• Input was based on punched cards and paper tapes, and output was displayed in printouts.
• Examples: - Mark I , UNIVAC, ENIAC, EDSAC, etc
Second generation computer (1956-1963) :( Transistor)
The main features of second generation computer are listed below:
• Transistors replaced vacuum tubes and emerged in the second generation computer.
• Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instruction in words.
• High-level programming languages were also being developed at this time, such as early version of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from magnetic drums to magnetic core technology.
• Magnet core memory was used as internal storage and magnetic tapes used as secondary storage.
• They have little bit faster I/O devices (input/output).
• Processing speed measured in micro-seconds.
• Example: IBM 1401, 7070, 7030, ICL 2950/10, Honeywell 800, 400 series. Etc.
Third generation computer (1964-1971): (Integrated Circuits IC)
The main features of third generation computer are listed below:
• Semi conductor memory was used as primary storage and magnetic discs were used as secondary storage.
• Massive use of high level language.
• Processing speed increased to nanosecond and even faster.
• Intend of punched cards and printouts, users interacted with third generation computers though keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory.
• Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.
• Examples- IBM 360 series, UNIVAC 9000, GE 235, Honeywell 200, Burroughs 6700 .Etc.
Fourth generation computers (1971-present): (VLSI or microprocessor)
The main features of fourth generation computer are listed below:
• Massive use of magnetic and optical storage devices with capacity more than 100 GB
• Advancement in software and high level language.
• Use of 4th generation language (4GL).
• Operation speed increased beyond picoseconds and MIPS( Millions of Instructions Per Second)
• As this computer became more powerful, they could be linked together to form network, which eventually led to the development of internet. Fourth generation computer also saw the development of GUI’s the mouse and hand held devices.
• Example: - IBM PC, Pentium PC, Apple/Macintosh etc.
Fifth generation computer (Present and beyond): (Biochips)
The main features of fifth generation computer are listed below:
• Fifth generation computing devices based on artificial intelligence, are still in development, though there are some application such as voice recognition, that are widely used today. It is also known as Artificial Intelligence.
• Currently no computers exhibit full artificial intelligence (that is, are able to simulate human behavior or behave like human beings or think as human beings). The greatest advances have occurred in the field of gaming like 3D games. The best example is a chess program that is able to beat humans.
• The fifth generation computers will have this following features like interactive game playing, expert system, understanding natural language, neural networks, robotics, acting like an human, can have own thinking capacity.
This is all about the generation of computer.
First generation of computer (1945-1956) :( Vacuum tubes)
The main features of first generation computer are listed below:
• It used vacuum tube as electronic circuit.
• The magnetic drums were used as primary storage and punch cards were used as secondary device.
• They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctioning.
• First generation of computers fully depends upon machine language to perform operations, and they could only solve one problem at a time.
• Operating speed was used in terms of millisecond. Every CPU has its own unique machine language. Programs must be rewritten or recompiled, therefore to run in different types of computer.
• Input was based on punched cards and paper tapes, and output was displayed in printouts.
• Examples: - Mark I , UNIVAC, ENIAC, EDSAC, etc
Second generation computer (1956-1963) :( Transistor)
The main features of second generation computer are listed below:
• Transistors replaced vacuum tubes and emerged in the second generation computer.
• Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instruction in words.
• High-level programming languages were also being developed at this time, such as early version of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from magnetic drums to magnetic core technology.
• Magnet core memory was used as internal storage and magnetic tapes used as secondary storage.
• They have little bit faster I/O devices (input/output).
• Processing speed measured in micro-seconds.
• Example: IBM 1401, 7070, 7030, ICL 2950/10, Honeywell 800, 400 series. Etc.
Third generation computer (1964-1971): (Integrated Circuits IC)
The main features of third generation computer are listed below:
• Semi conductor memory was used as primary storage and magnetic discs were used as secondary storage.
• Massive use of high level language.
• Processing speed increased to nanosecond and even faster.
• Intend of punched cards and printouts, users interacted with third generation computers though keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory.
• Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.
• Examples- IBM 360 series, UNIVAC 9000, GE 235, Honeywell 200, Burroughs 6700 .Etc.
Fourth generation computers (1971-present): (VLSI or microprocessor)
The main features of fourth generation computer are listed below:
• Massive use of magnetic and optical storage devices with capacity more than 100 GB
• Advancement in software and high level language.
• Use of 4th generation language (4GL).
• Operation speed increased beyond picoseconds and MIPS( Millions of Instructions Per Second)
• As this computer became more powerful, they could be linked together to form network, which eventually led to the development of internet. Fourth generation computer also saw the development of GUI’s the mouse and hand held devices.
• Example: - IBM PC, Pentium PC, Apple/Macintosh etc.
Fifth generation computer (Present and beyond): (Biochips)
The main features of fifth generation computer are listed below:
• Fifth generation computing devices based on artificial intelligence, are still in development, though there are some application such as voice recognition, that are widely used today. It is also known as Artificial Intelligence.
• Currently no computers exhibit full artificial intelligence (that is, are able to simulate human behavior or behave like human beings or think as human beings). The greatest advances have occurred in the field of gaming like 3D games. The best example is a chess program that is able to beat humans.
• The fifth generation computers will have this following features like interactive game playing, expert system, understanding natural language, neural networks, robotics, acting like an human, can have own thinking capacity.
This is all about the generation of computer.
Characteristics of computer:
All digital computers, regardless of their size are used to transmit, store and manipulate information (data). Several different types of data can be processed by a computer. These include numeric, data character data, graphic data and sound etc. the most common two types of data is numeric data and character data. Scientific and technical application is mostly concerned with numeric data where as business field requires both numeric as well as character data.
To process a particular set of data, the computer must be given a appropriate set of instruction that is called the program as we discussed it above. These instructions are entered into the computer and it is stored in a portion of computer’s memory.
A stored program can be executed at any time as our want. For example:
1. A set of instruction that is input data will be entered into the computer through input device called keyboard and is stored in a portion of computer’s memory known as hard disk.
2. The input data will be processed to produce certain desired result as an output.
3. And finally the output will be printed in a sheet of paper or displayed through out put device known as monitor.
These three things can be repeated as many times we want and processing of it depends upon how much is to be calculated or processed.
To process a particular set of data, the computer must be given a appropriate set of instruction that is called the program as we discussed it above. These instructions are entered into the computer and it is stored in a portion of computer’s memory.
A stored program can be executed at any time as our want. For example:
1. A set of instruction that is input data will be entered into the computer through input device called keyboard and is stored in a portion of computer’s memory known as hard disk.
2. The input data will be processed to produce certain desired result as an output.
3. And finally the output will be printed in a sheet of paper or displayed through out put device known as monitor.
These three things can be repeated as many times we want and processing of it depends upon how much is to be calculated or processed.
History of computer:
- A brief history of computer is pointed below:
History of computer was started when the people in the early civilization started keeping records of transaction on clay. This was the starting of history of computer in 1200BC.
• Actual computing started around 300BC when Babylon invented the ABACUS.
• In 1642, Blaise pascal invented a gear driven adding machine which we called a calculator now a days but its name was PASCALENE, which was the first mechanical adding machine.
• In 1673, Leibnitz developed a machine named STEPPED RECKONER that could multiply.
• In 1801, jacquard constructed a LOOM, which was the first machine programmed with punched cards.
• In 1822, Charles Babbage designed and build first DIFFERENCE ENGINE which was certificated the first mechanical computer. So he is known as the father of computer science.
• In 1842, lady Ada Augusta Lovelance wrote the first program for the difference engine made by Babbage.
• In 1847, Babbage designed his second version of difference engine but it could not be completed and was conceived on 1891 by the science museum in England.
• In 1854, George Bool developed Boolean logic, which is the system for symbolic and logical reasoning and basis for computer design.
• In 1890, PUNCHED CARD machine was developed in USA.
• Before the development of vacuum tubes all the machines were mechanical.
• The first electronic computer ENIAC (electronic numerical integrators and computer) was built in 1946.
• After the many machine like EDVAC (Electronic discrete variable automatic computer), IBM 701, 704 were built using transistors instead of vacuum tubes.
• In 1961, integrated circuit(IC) chips were commercially available.
• Science then computers uses ic’s instead of transistors.
• IBM 360 (international business machine) and DEC PDP 8 (programmed data processor, digital equipment corporation) were the most popular machine at that time.
• Altair 8800 was the first easily available PC(personal computer)
• In 1891, IBM launched the PC.
• Science then, there has been significant development in the field of microelectronics and microprocessor.
• Today there are lots of microprocessor with more then 2GHz (Gigahertz) processor on our desktop and 8 GB (Gigabyte) and more of memory and more than 500GB (Gigabyte) of storage.
What is computer?
A digital computer is such an invention of 20th century that has widely spread in each and every field of human life. A digital computer is an electronic programmable machine that can process almost all kinds of data. The programmable feature has made this machine unique as compared to other machines. The same machine can be used in small shop, in medical science, for space-research and various engineering activities. All this is possible by using different programs for different environment/applications. What is a program? A program is a set of instructions, written in particular sequence in a computer-related language.
Introduction: to Computer
Computer simply is defined as an electronic device which calculates the raw data given by user and gives the valuable result as an output.
Today’s computers come in many different forms. They range from massive, multipurpose mainframes and supercomputers to desktop-size personal computers. Between these extremes is a vast middle ground of minicomputers and workstations. Large minicomputers approach mainframes in computing power, whereas workstations are powerful personal computers.
Mainframes and large minicomputers are used by many businesses, universities, hospitals and government agencies to carry out sophisticated scientific and business calculations. These computers are expensive (large computers can cost millions of dollars) and may require a sizeable staff of supporting personal and a special carefully controlled environment.
Personal computer on the other hand is small and expensive. In fact, portable, laptop computers weighing less then 5-6 pounds are widely used by everyone now days. Personal computers are mostly used by schools and business and it is being used in household items too. Now days computers is thought from the primary level that is from 5 on words some school used it from the class 3 too.
This is the generation of computer, each and every field is using computer, it is said that this 21st century age is known as computer age. If one fails to take the knowledge of computer then it is believed that he/she can’t do anything in his life. The cost of these personal computers is so low that a single family can afford 2 of it; each and every family has got one computer.
Today’s computers come in many different forms. They range from massive, multipurpose mainframes and supercomputers to desktop-size personal computers. Between these extremes is a vast middle ground of minicomputers and workstations. Large minicomputers approach mainframes in computing power, whereas workstations are powerful personal computers.
Mainframes and large minicomputers are used by many businesses, universities, hospitals and government agencies to carry out sophisticated scientific and business calculations. These computers are expensive (large computers can cost millions of dollars) and may require a sizeable staff of supporting personal and a special carefully controlled environment.
Personal computer on the other hand is small and expensive. In fact, portable, laptop computers weighing less then 5-6 pounds are widely used by everyone now days. Personal computers are mostly used by schools and business and it is being used in household items too. Now days computers is thought from the primary level that is from 5 on words some school used it from the class 3 too.
This is the generation of computer, each and every field is using computer, it is said that this 21st century age is known as computer age. If one fails to take the knowledge of computer then it is believed that he/she can’t do anything in his life. The cost of these personal computers is so low that a single family can afford 2 of it; each and every family has got one computer.
Monday, July 12, 2010
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