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A computer is a machine (mostly electronic) that is able to take information (input), and process it to make new information (output).
Calculating machines are old in the history of technology. Early examples are the astrolabe and the abacus. Today a computer is a programmable machine. The two principal characteristics of a computer are: It responds to a specific instruction set in a well-defined manner and it can execute a prerecorded list of instructions (a program). There are four main processing steps in a computer: inputting, storage, outputting 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, and touch screens. Some very sophisticated 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 programs are designed or written by computer programmers. A few programmers write programs in the computer's own language called machine code. Most programs are written using a programming language like C++, Java, and Fortran. These programming languages are more like the language with which one talks and writes every day. The compiler translates the user's instructions into binary code (machine code) that the computer will understand and do what is needed.
History of computers[change | change source]
Definition[change | change source]
A computer is a programmable electronic device designed to accept data, perform prescribed mathematical and logical operations at high speed, and display the results of these operations, all under the control of software. Mainframes, desktop and laptop computers, tablets and smartphones are some of the different types of computers. An electronic machine which helps in solving problems quickly and easily. It solves problems according to instructions given to it by the computer user called programs or software. It is a digital machine(that uses binary digits) used in all fields.
Automation[change | change source]
Most humans have a problem with math. To show this, try doing 584 × 3,220 in your head. It is hard to remember all the steps! People made tools to help them remember where they were in a maths problem. The other problem people have is that they have to do the same problem over and over and over again. A cashier had to make change every day in her head or with a piece of paper. That took a lot of time and made mistakes. So, people made calculators that did those same things over and over. This part of computer history is called the "history of automated calculation," which is a fancy phrase for "the history of machines that make it easy for me to do this same maths problem over and over without making mistakes."
The abacus, the slide rule, the astrolabe and the Antikythera mechanism (which dates from about 150-100 BC) are examples of automated calculation machines.
Programming[change | change source]
Main article: Computer programming
People did not want a machine that would do the same thing over and over again. For example, a music box is a machine that plays the same music over and over again. Some people wanted to be able to tell their machine to do different things. For example, they wanted to tell the music box to play different music every time. They wanted to be able to program the music box- to order the music box to play different music. This part of computer history is called the "history of programmable machines" which is a fancy phrase for "The history of machines that I can order to do different things if I know how to speak their language."
One of the first examples of this was built by Hero of Alexandria (c. 10–70 AD). He built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums. These ropes and drums were the language of the machine- they told what the machine did and when. Some people argue that this is the first programmable machine.
Historians disagree on which early machines are "computers". Many say the "castle clock", an astronomical clock invented by Al-Jazari in 1206, is the first known programmableanalog computer. Others say the first computer was made by Charles Babbage.Al - Jazari's showed the zodiac, the solar and lunar orbits, a crescent moon-shaped pointer travelling across a gateway that made some doors to open every hour, and five robotic musicians who play music when levers hit them. The length of day and night could be changed (AKA re-programmed) every day in order to account for the changing lengths of day and night throughout the year.Ada Lovelace is considered to be the first programmer.
The Computing Era[change | change source]
At the end of the Middle Ages, people in Europe thought math and engineering were more important. In 1623, Wilhelm Schickard made a mechanical calculator. Other Europeans made more calculators after him. They were not modern computers because they could only add, subtract, and multiply- you could not change what they did to make them do something like play Tetris. Because of this, we say they were not programmable. Now engineers use computers to design and plan.
In 1801, Joseph Marie Jacquard used punched paper cards to tell his textile loom what kind of pattern to weave. He could use punch cards to tell the loom what to do, and he could change the punch cards, which means he could program the loom to weave the pattern he wanted. This means the loom was programmable.
Charles Babbage wanted to make a similar machine that could calculate. He called it "The Analytical Engine". Because Babbage did not have enough money and always changed his design when he had a better idea, he never built his Analytical Engine.
As time went on, computers were used more. People get bored easily doing the same thing over and over. Imagine spending your life writing things down on index cards, storing them, and then having to go find them again. The U.S. Census Bureau in 1890 had hundreds of people doing just that. It was expensive, and reports took a long time. Then an engineer worked out how to make machines do a lot of the work. Herman Hollerith invented a tabulating machine that would automatically add up information that the Census bureau collected. The Computing Tabulating Recording Corporation (which later became IBM) made his machines. They leased the machines instead of selling them. Makers of machines had long helped their users understand and repair them, and CTR's tech support was especially good.
Because of machines like this, new ways of talking to these machines were invented, and new types of machines were invented, and eventually the computer as we know it was born.
Analog and Digital Computers[change | change source]
In the first half of the 20th century, scientists started using computers, mostly because scientists had a lot of math to figure out and wanted to spend more of their time thinking about science questions instead of spending hours adding numbers together. For example, if they had to launch a rocket ship, they needed to do a lot of math to make sure the rocket worked right. So they put together computers. These analog computers used analog circuits, which made them very hard to program. In the 1930s, they invented digital computers, and soon made them easier to program.
High-scale computers[change | change source]
Scientists figured out how to make and use digital computers in the 1930s and 1940s. Scientists made a lot of digital computers, and as they did, they figured out how to ask them the right sorts of questions to get the most out of them. Here are a few of the computers they built:
- Konrad Zuse's electromechanical "Z machines". The Z3 (1941) was the first working machine that used binary arithmetic. Binary arithmetic means using "Yes" and "No." to add numbers together. You could also program it. In 1998 the Z3 was proved to be Turing complete. Turing complete means that it is possible to tell this particular computer anything that it is mathematically possible to tell a computer. It is the world's first modern computer.
- The non-programmable Atanasoff–Berry Computer (1941) which used vacuum tubes to store "yes" and "no" answers, and regenerative capacitor memory.
- The Harvard Mark I (1944), A big computer that you could kind of program.
- The U.S. Army's Ballistics Research Laboratory ENIAC (1946), which could add numbers the way people do (using the numbers 0 through 9) and is sometimes called the first general purpose electronic computer (since Konrad Zuse's Z3 of 1941 used electromagnets instead of electronics). At first, however, the only way to reprogram ENIAC was by rewiring it.
Several developers of ENIAC saw its problems. They invented a way to for a computer to remember what they had told it, and a way to change what it remembered. This is known as "stored program architecture" or von Neumann architecture. John von Neumann talked about this design in the paper First Draft of a Report on the EDVAC, distributed in 1945. A number of projects to develop computers based on the stored-program architecture started around this time. The first of these was completed in Great Britain. The first to be demonstrated working was the Manchester Small-Scale Experimental Machine (SSEM or "Baby"), while the EDSAC, completed a year after SSEM, was the first really useful computer that used the stored program design. Shortly afterwards, the machine originally described by von Neumann's paper—EDVAC—was completed but was not ready for two years.
Nearly all modern computers use the stored-program architecture. It has become the main concept which defines a modern computer. The technologies used to build computers have changed since the 1940s, but many current computers still use the von-Neumann architecture.
In the 1950s computers were built out of mostly vacuum tubes. Transistors replaced vacuum tubes in the 1960s because they were smaller and cheaper. They also need less power and do not break down as much as vacuum tubes. In the 1970s, technologies were based on integrated circuits. Microprocessors, such as the Intel 4004 made computers smaller, cheaper, faster and more reliable. By the 1980s, microcontrollers became small and cheap enough to replace mechanical controls in things like washing machines. The 1980s also saw home computers and personal computers. With the evolution of the Internet, personal computers are becoming as common as the television and the telephone in the household.
In 2005 Nokia started to call some of its mobile phones (the N-series) "multimedia computers" and after the launch of the Apple iPhone in 2007, many are now starting to add the smartphone category among "real" computers. In 2008, if smartphones are included in the numbers of computers in the world, the biggest computer maker by units sold, was no longer Hewlett-Packard, but rather Nokia.[source?]
Kinds of computers[change | change source]
There are many types of computers:
- personal computer
- Workstation computer
- mainframe computer
- embedded system
- Tablet computer
A "desktop computer" is a small machine that has a screen (which is not part of the computer). Most people keep them on top of a desk, which is why they are called "desktop computers." "Laptop computers" are computers small enough to fit on your lap. This makes them easy to carry around. Both laptops and desktops are called personal computers, because one person at a time uses them for things like playing music, surfing the web, or playing video games.
There are bigger computers that many people at a time can use. These are called "Mainframes," and these computers do all the things that make things like the internet work. You can think of a personal computer like this: the personal computer is like your skin: you can see it, other people can see it, and through your skin you feel wind, water, air, and the rest of the world. A mainframe is more like your internal organs: you never see them, and you barely even think about them, but if they suddenly went missing, you would have some very big problems.
An embedded computer, also called embedded system is a computer that does one thing and one thing only, and usually does it very well. For example, an alarm clock is an embedded computer: it tells the time. Unlike your personal computer, you cannot use your clock to play Tetris. Because of this, we say that embedded computers cannot be programmed, because you cannot install more programs on your clock. Some mobile phones, automatic teller machines, microwave ovens, CD players and cars are operated by embedded computers.
All-in-one PC[change | change source]
All-in-one computers are desktop computers that have all of the computer's inner mechanisms in the same case as the monitor. Apple has made several popular examples of all-in-one computers, such as the original Macintosh of the mid-1980s and the iMac of the late 1990s and 2000s.
Common uses of home computers[change | change source]
Common uses of work computers[change | change source]
- Word processing
- Spreadsheets (Excel)
- PowerPoint Presentations
- Photo Editing (Photoshop, GIMP)
- Video editing/rendering/encoding
- Audio recording
- System Management
Working methods[change | change source]
Computers store data and the instructions as numbers, because computers can do things with numbers very quickly. These data are stored as binarysymbols (1s and 0s). A 1 or a 0 symbol stored by a computer is called a bit, which comes from the words binary digit. Computers can use many bits together to represent instructions and the data that these instructions use. A list of instructions is called a program and is stored on the computer's hard disk. Computers work through the program by using a central processing unit, and they use fast memory called RAM as a space to store the instructions and data while they are doing this. When the computer wants to store the results of the program for later, it uses the hard disk because things stored on a hard disk can still be remembered after the computer is turned off.
An operating system tells the computer how to understand what jobs it has to do, how to do these jobs, and how to tell people the results. Millions of computers may be using the same operating system, while each computer can have its own application programs to do what its user needs. Using the same operating systems makes it easy to learn how to use computers for new things. A user who needs to use a computer for something different, can learn how to use a new application program. Some operating systems can have simple command lines or a fully user-frendly GUI.
The Internet[change | change source]
One of the most important jobs that computers do for people is helping with communication. Communication is how people share information. Computers have helped people move forward in science, medicine, business, and learning, because they let experts from anywhere in the world work with each other and share information. They also let other people communicate with each other, do their jobs almost anywhere, learn about almost anything, or share their opinions with each other. The Internet is the thing that lets people communicate between their computers.
Computers and waste[change | change source]
A computer is now almost always an electronic device. It usually contains materials that will become electronic waste when discarded. When a new computer is bought in some places, laws require that the cost of its waste management must also be paid for. This is called product stewardship.
Computers can become obsolete quickly, depending on what programs the user runs. Very often, they are thrown away within two or three years, because some newer programs require a more powerful computer. This makes the problem worse, so computer recycling happens a lot. Many projects try to send working computers to developing nations so they can be re-used and will not become waste as quickly, as most people do not need to run new programs. Some computer parts, such as hard drives, can break easily. When these parts end up in the landfill, they can put poisonous chemicals like lead into the ground water. Hard drives can also contain secret information like credit card numbers. If the hard drive is not erased before being thrown away, an identity thief can get the information from the hard drive, even if the drive doesn't work, and use it to steal money from the previous owner's bank account.
Main hardware[change | change source]
Computers come in different forms, but most of them have a common design.
- All computers have a CPU.
- All computers have some kind of data bus which lets them get inputs or output things to the environment.
- All computers have some form of memory. These are usually chips (integrated circuits) which can hold information.
- Many computers have some kind of sensors, which lets them get input from their environment.
- Many computers have some kind of display device, which lets them show output. They may also have other peripheral devices connected.
A computer has several main parts. When comparing a computer to a human body, the CPU is like a brain. It does most of the 'thinking' and tells the rest of the computer how to work. The CPU is on the Motherboard, which is like the skeleton. It provides the basis for where the other parts go, and carries the nerves that connect them to each other and the CPU. The motherboard is connected to a power supply, which provides electricity to the entire computer. The various drives (CD drive, floppy drive, and on many newer computers, USB flash drive) act like eyes, ears, and fingers, and allow the computer to read different types of storage, in the same way that a human can read different types of books. The hard drive is like a human's memory, and keeps track of all the data stored on the computer. Most computers have a sound card or another method of making sound, which is like vocal cords, or a voice box. Connected to the sound card are speakers, which are like a mouth, and are where the sound comes out. Computers might also have a graphics card, which helps the computer to create visual effects, such as 3D environments, or more realistic colors, and more powerful graphics cards can make more realistic or more advanced images, in the same way a well trained artist can.
Largest Computer Companies[change | change source]
References[change | change source]
- ↑"Heron of Alexandria". Retrieved 2008-01-15.
- ↑ 2.02.1Ancient Discoveries, Episode 11: Ancient Robots, History Channel, retrieved 2008-09-06
- ↑Howard R. Turner (1997), Science in Medieval Islam: An Illustrated Introduction, p. 184, University of Texas Press, ISBN 0-292-78149-0
- ↑Donald Routledge Hill, "Mechanical Engineering in the Medieval Near East", Scientific American, May 1991, pp. 64-9 (compare Donald Routledge Hill, Mechanical Engineering)
- ↑Fuegi & Francis 2003, pp. 16–26.
- ↑Phillips, Ana Lena (November–December 2011). "Crowdsourcing gender equity: Ada lovelace day, and its companion website, aims to raise the profile of women in science and technology". American Scientist99 (6): 463.
- ↑"Ada Lovelace honoured by Google doodle", The Guardian, 2012 Dec 10, retrieved 10 December 2012 .
- ↑Don't confuse the Analytical Engine with Babbage's difference engine which was a non-programmable mechanical calculator.
Other websites[change | change source]
Internet is a network of networks which connects computers worldwide through the standardized communication protocols (like TCP/IP) using which we can access information at any computer.
Essay on Internet
Internet is a big hand of today’s success of the people. Let your kids and school going children know something about internet like its advantages and disadvantages. It helps in drawing their mind towards study a lot. All the essay on internet are written in very simple words especially for the use of students. You can select any internet essay given below:
Internet Essay 1 (100 words)
Internet is the invention of modern and high technology science. It provides us amazing facility of searching any information from any corner of the world by anyone. We can connect more than one computer to each other using this internet in order to easily access information from any connected computer from one place. Using internet we can send any big or small message, information very quickly within seconds to anyone’s computer, mobile or other digital device like tablets, PC, etc. It is a vast storage of information as it has more than billions of running websites related to the domestic, business, academic, governmental, etc. We can say it is a network of networks.
Internet Essay 2 (150 words)
The Internet is a very vast network of networks using which we can access any information stored within it from any corner of the world. It is accessed anywhere through a telecommunications line and modulator-demodulator and comes to the computer by modifying analogue telephone signals into the digital computer signals. The invention of the internet has brought uncounted advantages to us however we cannot turn our face from its disadvantages. Internet is used all over the world for many purposes including sending electronic mail, messaging, online chat, transferring file, access web pages and other documents over World Wide Web.
We can access the World Wide Web once we have internet connection. Opening web pages we can get any type of information which we required to fulfill our purpose. There is no any time limit to open web pages, we can open it for 1 min or 1 hr or can save pages for later use. We can prepare our projects works very easily and timely.
Internet Essay 3 (200 words)
Internet has made everyone’s life very easy and simple as we no longer need to go outside for paying bill, shopping, seeing movie, business transactions, etc. It has been an essential part of our life means we can say that without it we face lots of problems in our daily lives. Because of its easiness and usefulness, it is used everywhere such as workplace, offices, schools, colleges, banks, education institutions, training centres, shops, railways station, airports, restaurants, hotels, malls, and most importantly at home by each members for different purposes. Once we take the internet connection by paying money to the Internet Service Provider, we can access the internet facility anytime from any corner of the world for one week or month according to the internet plan we have taken.
From the time internet has come in our life, our world has become changed to a great extent in the positive ways however in the negative ways too. It is highly beneficial for the students, businessmen, government agencies, research organizations, etc. Students can search any needed information for their study, businessmen can deal their business matters from one place, government agencies can do their work in proper time, research organizations can research more and give outstanding results, etc.
Internet Essay 4 (250 words)
Internet has revolutionized the living style and working style of the human being. It has reduced the man effort and time thus very beneficial to all for gaining knowledge as well as increase income at less input. It has ability to provide information within no time at the doorstep. Basically internet is a network of networks which connects various computers to handle from one place. Now a day, internet has spread its effects at every nook and corner all over the world. Accessing internet require a telephone line, a computer and a modem.
It helps in getting worldwide information online from any place of the world. It helps in gathering, collecting and storing information to our computer from the websites on any topic within seconds. There is a computer and internet facility in my computer lab in the school where we access needed information for our project. My computer teacher assists me about how to get online information and use in appropriate manner.
It has made online communication fast and easy so that people can communicate with each other located anywhere in the world via video-conferences or just messaging. Students can take help of internet to get prepare for their exam, to prepare their projects, to get participated in the extra-curricular activities and many more. Students can contact their teachers online to discuss some unsolved questions or friends for many purposes. Using internet we can get information about anything in this world like real address and exact distance of the destination we want to go to travel, etc.
Internet Essay 5 (300 words)
In the modern time, internet has become is one of the most powerful and interesting tools all across the world. The Internet is a network of networks and collection of many services and resources which benefits us in various ways. Using internet we can access World Wide Web from any place. It provides bulk of facilities to us such as E-mail, surfing search engines, connecting to celebrities using social media websites, accessing web portals, opening informative websites, being up-to-date, video chatting and many more. It has become best ever friend of everyone’s. Now a day, almost everyone is using internet connection for many purposes. However, we should know all the disadvantages and advantages of using internet in our life.
Internet availability is very useful for the students however it is a big concern too for them as they can access some bad websites secretly from their parents which is very harmful to their whole life. Most of the parents realize this type of danger however some not and use internet openly. So, children should use internet facility under the proper guidance of their parents.
We can use security system by using username and password to prevent others to access our precious online data. Internet allow us to use any application programmes supporting instant messaging to send quick messages to friends, parents or teachers. However, in some other countries (North Korea, Myanmar, etc) it is totally prohibited to use internet as they think that it is bad thing for them. Sometimes, internet can harm our computer as downloading anything directly from the internet websites may bring some viruses, adware, malware, spyware or other bad programmes to our computer which can disturb or destroy the computer functioning. Sometimes, hackers can hack our secret computer information using internet without our knowledge even after password security.
Internet Essay 6 (400 words)
Internet is a global network which connects millions of computers all over the world. It has become very simple and easy in accomplishing all day to day activities which were very time taking and hard to manage in those days. We cannot think our life without this great invention called internet. As everything has its pros and cons means both positive and negative effects, internet also has affected the human lives in both ways. Because of the internet, online communication has become very easy and simple. The mode of communication in those days were through letters which was very time taking and hard as one had to travel a long distance. But now, we just need to connect our internet to open some social networking websites and opening Gmail or other accounts (Yahoo, etc) to send messages within seconds.
It has reduced the usage of paper and paper works to a great extent by making everything computerized in the offices (governmental or non-governmental), schools, colleges, educational institutions, training centres, NGOs, universities, shops, business, industries, railway, metro and many more. Using this internet we can get all the news time to time from all across the world from one place. It is very effective and efficient in gathering huge information whether required for references or activities on any topic within seconds. It has benefited the education, travel and business sectors to a great level. It has made easy access to the online public libraries, textbooks or other resources to find relevant topics.
In the earlier time when people were without internet, they had to waste lots of time for any type of work like standing in the long queues and waiting for their number to get travel ticket. But in the modern time of internet, one can book train online in just few clicks and get travel ticket through printout or get a soft copy in his/her mobile. In the internet world, one does not need to travel a long distance for his/her meeting for business or other purposes. One can attend his/her meeting online from own office through the use of video calling, conferencing, Skype or using other tools. It helps in getting admission online in his/her desired school, college or universities, hiring highly skilled employees and teachers, business transactions, banking transactions, applying for driving license, money transfer, learning cooking recipes, bill payment, purchasing anything on free delivery and so many activities.
Essay on Uses of Internet
Essay on Disadvantages of Internet