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What is computer?

A computer is a machine (mostly electronic) that is able to take information (input), do some work on or make changes to the information (process), to make new information (output). Computers have existed for much of human history. Examples of early computers are the astrolabe and the abacus. There are four main processing steps in a computer, and they are: inputting, outputting, storage and processing.

Modern computers are very different from early computers. They can do billions of calculations per second. Most people have used a personal computer in their home or at work. Computers do many different jobs where automation is useful. Some examples are controlling traffic lights, vehicle computers, security systems, washing machines and digital televisions.

A computer user can control it by a user interface. Input devices include keyboard, mouse, buttons, touch screen. Some very new computers can also be controlled with voice commands or hand gestures or even brain signals through electrodes implanted in the brain or along nerves.

Computers can be designed to do almost anything with information. Computers are used to control large and small machines which in the past were controlled by humans. They are also in homes, where they are used for things such as listening to music, reading the news, and writing.

Modern computers are electronic computer hardware. They do mathematical arithmetic very quickly but computers do not really "think". They only follow the instructions in their software programs. The software uses the hardware when the user gives it instructions, and gives useful output.


Computer generations:-

First generation (1946-1959):-

The period of first generation 1946-1959. Vacuum tube based. The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit). These tubes, like electric bulbs, produced a lot of heat and were prone to frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organisations. In this generation mainly batch processing operating system were used. Punched cards, paper tape, and magnetic tape were used as input and output devices. The computers in this generation used machine code as programming language.

The main features of first generation are:

Vacuum tube technology, Unreliable, Supported machine language only, Very costly, generated lot of heat, Slow input and output devices, Huge size, Need of A.C., Non-portable, Consumed lot of electricity etc.

Some computers of this generation were:



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Second Generation (1959-1965):-

The period of second generation was 1959-1965. In this generation transistors were used that were cheaper, consumed less power, more compact in size, more reliable and faster than the first generation machines made of vacuum tubes. In this generation, magnetic cores were used as primary memory and magnetic tape and magnetic disks as secondary storage devices. In this generation assembly language and high-level programming languages like FORTRAN, COBOL was used. The computers used batch processing and multiprogramming operating system.

The main features of second generation are:

Use of transistors, Reliable in comparison to first generation computers, Smaller size as compared to first generation computers, Generated less heat as compared to first generation computers, Consumed less electricity as compared to first generation computers, Faster than first generation computers, Still very costly, A.C. needed, Supported machine and assembly languages etc.

Some computers of this generation were:

IBM 1620, IBM 7094, CDC 1604, CDC 3600, UNIVAC 1108 etc.


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Third Generation (1965-1971):-

The period of third generation was 1965-1971. The computers of third generation used integrated circuits (IC's) in place of transistors. A single IC has many transistors, resistors and capacitors along with the associated circuitry. The IC was invented by Jack Kilby. This development made computers smaller in size, reliable and efficient. In this generation remote processing, time-sharing, multi-programming operating system were used. High-level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68 etc.) were used during this generation.

The main features of third generation are:

IC used, More reliable in comparison to previous two generations, Smaller size, Generated less heat, Faster, Lesser maintenance

Still costly, A.C needed, consumed lesser electricity, Supported high-level language etc.

Some computers of this generation were:

IBM-360 series, Honeywell-6000 series, PDP (Personal Data Processor), IBM-370/168, TDC-316 etc.


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Fourth Generation (1971-1980):-

The period of fourth generation was 1971-1980. The computers of fourth generation used Very Large Scale Integrated (VLSI) circuits. VLSI circuits having about 5000 transistors and other circuit elements and their associated circuits on a single chip made it possible to have microcomputers of fourth generation. Fourth generation computers became more powerful, compact, reliable, and affordable. As a result, it gave rise to personal computer (PC) revolution. In this generation time sharing, real time, networks, distributed operating system were used. All the high-level languages like C, C++, DBASE etc., were used in this generation.

The main features of fourth generation are:

VLSI technology used, Very cheap, Portable and reliable, Use of PC's, Very small size, Pipeline processing, No A.C. needed, Concept of internet was introduced, Great developments in the fields of networks, Computers became easily available etc.

Some computers of this generation were:

DEC 10, STAR 1000, PDP 11, CRAY-1(Super Computer), CRAY-X-MP(Super Computer) etc.


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Fifth Generation (1980-till date):-

The period of fifth generation is 1980-till date. In the fifth generation, the VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components. This generation is based on parallel processing hardware and AI (Artificial Intelligence) software. AI is an emerging branch in computer science, which interprets means and method of making computers think like human beings. All the high-level languages like C and C++, Java, .Net etc., are used in this generation.

AI includes:

Robotics, Neural Networks, Game Playing, Development of expert systems to make decisions in real life situations, Natural language understanding and generation.

The main features of fifth generation are:

ULSI technology, Development of true artificial intelligence, Development of Natural language processing, Advancement in Parallel Processing, Advancement in Superconductor technology, more user friendly interfaces with multimedia features, Availability of very powerful and compact computers at cheaper rates etc.

Some computer types of this generation are:

Desktop, Laptop, NoteBook, UltraBook, ChromeBook etc.


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Effects of Computer on human health:-

1. Computer use can result in vision problems called Computer Vision Syndrome (CVS).

2. People who have used the computers for an extensive period of time may complain about headaches, and pains in their wrists, arms and necks.

3. Many computers have CRT, or Cathode Ray Tube, monitors that give off X-ray radiation that can affect your health.

4. Being exposed to computer radiation can cause cancer, tumours, miscarriage and birth defects, headaches and insomnia.

5. This can put more stress on your eyes.

6. Symptoms of CVS include eye strain, blurred vision, headaches and dry eyes.

7. These pains are often the result of a fixed posture when using the computer keyboard for a long amount of time.


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Effects of Computer on environment:-

1. Computer product often contains hazardous and toxic material that poses environmental risks if they are landfill or in chin erased.

2. The Materials that are used for cleaning computer equipment are harmful for the environment and all the chemicals that are released in the process cause pollution for the ground water and harm humans and it’s extremely harmful for the ozone.

3. A lot of people think that computers don’t hurt the environment, but they can cause a lot of pollution to Silicon Valley but as the computers itself it does not disturb nature; Computers may even have certain environmental advantages.

4. Computers pollution is a big problem that most people don’t know about and it has to be solved quickly.

5. They save paper and they keep us from harming the nature by being glued to the screen because we often harm the environment when we take the time to live our live without electronic technology.


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