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What is computer? Computers are getting more important in our daily life now. Computer can be found in this world everywhere because of the rise high technology in today's world. What does computer really means? Computer is an electronic device can accept the information from user and manipulate it from some result based on the instructions that given by users on how the data is to be processed. Complex computers also include the means for storing data for some necessary duration. Computers also include the means for storing data for some necessary duration. Computers possess a lot of advantages which are speed, reliability, consistency, storage, and communications. They perform the operations at extremely speeds, and they are dependable and reliable, which consistently generate error-free results. They also can store huge amounts of data, and can share processing with other computers. Computers are playing important role in today's society in various fields.
In education fields, computer also played an important role to student. Many students do not go to the library anymore. This is because on Internet we can find plenty of encyclopedias and many education sites when we browse through different Internet sites by using search engine on the Internet. Almost every school has some computers which have access to Internet and students can use those computers for research which may help them to make their daily tasks.
At school, teacher use computer to assist with classroom instruction. Students complete assignments and conduct research on computer in lab rooms, at home or elsewhere. Instead of attending class on campus, some students take entire classes directly from their computer. People also spend hours of leisure time using a computer. They play game, listen to music or radio broadcasts, watch or compose video and movies, read books and magazines, share stories, research genealogy, retouch photos, and plan vacations.
Internet is not only a source of information for students. It is also used for communication with other students and even professors. There are several kinds of education where we need to consult a certain protected Internet page to know our daily tasks and even the date and hour when the courses take place. Many universities also announce the moment when the examinations take place. Email is certainly an advantage of Internet use in school. Every student can reach other students by email and even the professor can be consulted. It is impossible to imagine a world with education without use of Internet. The effect of the Internet is in most cases positive because the wealth of information but it is important that parents control their children that they don't use inappropriate sites. Internet will often improve the quality of education but it is always possible students don't use their time efficient.
As we can see it is impossible to imagine that education continues without the use of Internet and computers.
The computer also include in finance fields. Many people and companies use computer to help manage their finance. Some people use the finance software to balance check books, pay bills, track personal income and expenses, manage investments, and evaluate financial plans. A lot of people and companies use the computer to help manage their finance. Some of them use to check books balance, pay bills, track personal income and expenses, manage investments, and evaluate financial plans. The finance software mostly includes the online services within the software. Online banking can make users access account balances, pay bills, and copy monthly transactions from the bank's computer right into their personal computers in a short time.
As we know that computers can do calculation very fast and save a lot of time and store the documents and data in a large amount. The company use computers to save the customer details in computer which is database. This can make the company knows the details of their customer and prevents any cheating while dealing. Many financial institutions websites also offer online banking. When using a website instead of finance software on your computer, all your account information is stored on the bank's computer. The advantage is you can access your financial records from anywhere in the world.
In today's society, government also make use of the computer to do some services by online. Most of the governments in this world have official website for each country for their citizens to update their personal information for their identity. Governments also make use the Internet to maintain their system under control all the time. They can use the computer to store the information very fast and also can be stored in large of amount. This is because computer systems are reliable and the data cannot be erased or lost it easily.
People in the United States, they can access the government websites to check file taxes apply for permits and licenses, pay parking tickets, buy stamps, report crimes, apply for financial acid, and renew vehicle registrations and driver's licenses. Employees of government agencies use computers as part of their daily routine.
On the other hand, the government also can use computer system to do the emergency call such as Police station, Fire station, Ambulance service and help service. This system enables government transfer the correct information and location to the department to take action immediately without hesitated.
In Medical fields, computers are being involves in this fields also. Whether it is data management, diagnosis, or treatment, all computers have their own applications. As we know today in medicine fields might not have been possible without the valuable contribution of computers. Computers have been used as storage devices for medical information and patient information for many years. We can't imagine that all the information stored by using paper works because it easily lost and eat up many space. Computers can be based on patient records and it is a good example to prove the value of computers as information storage
Furthermore, computers can maintain the patient records, monitor patients, deliver medication to nurse stations via robots, assist with medical tests and research, correspond with patients, file insurance claims, provides greater precision during operations. All the patient information can be send to other hospital in just a few minutes time by using computers. Normally in hospital computers are used for scheduling and appointment.
In other hands, many websites are providing up-to- date medical, fitness, nutrition, or exercise information. These websites also maintain lists of doctors and dentists to help you find the one that suits your needs. Due to set up and running costs, possibility for mistreatment, poor functioning, and the risk of loss of confidentiality, they were not used frequently in the past.
In today's world, computers also involves in publishing fields. Publishing is the process of making works available to the public. With the advent of digital information systems and the Internet, the scope of publishing has expanded to include electronic resources, such as the electronic versions of books and periodicals, as well as micropublishing, websites, blogs and video games.
By doing publishing we need to have special software which assists graphic designers in developing pages that include text, graphics, and photos. Publishers use computers to assist them in design pages, create interesting web pages and make the content available online. The professional publishing system applications are being introduced because it can make the work easier and prefect. The variety of application programs which functions at the computer can design a lot of beautiful publishing pages fast and high definitions. Without the help of computers, publisher is impossible to publish creative pages. Computer are also played important role in publishing fields.
In travelling fields, small computers device can be set up in vehicles are called GPS. Many vehicles are using GPS online navigation system to help people travel faster and safer. With the help of Internet, we can order airline tickets online without step out from home and it takes about few minutes. We also can print directions of a map from the Web if need to onboard navigation systems. If we are lost in the middle of road, at this time GPS can help us to get out from there and continues our destination. The role of the GPS is show the map of the world and shows the way to travel by road.
Furthermore, whether travelling by car or airplane our goal is to arrive safely at our destination. Vehicles manufactured today are often includes some type of onboard navigation system with latest technology. Some mobile users prefer to carry specialized handheld navigation devices. In preparing for a trip, we may need to reserve a car, hotel, or flight. Without stepping out of the house, we can surf the Internet and reserve it. As we know many websites are offering these services to the public.
In today's world, the roles of computer in society are being more important. It can affect many fields such as education, finance, government, health care, publishing, and travel. Computers are really important to us in our daily life. We can't imagine that computers are not around us. The coming future, computers will become even more important and may affect more fields.
What is networking? Networking is a collection of computers and devices connected by communications channels that facilitates communications among users and allows users to share their resources with other users; such as hardware, software, data and information. Sharing resources saves time and money. In many networks, one or more computer act as a server. The server controls access to the resources on a network. The other computers on the network, each called a client or workstation, request resources from the server.
There are big differences between the server and the client computers. Between them the server ordinarily has more power, more storing space, and expanded communications capabilities. The client computer is hosted by server. It shows server computers are powerful then client computers. At homes, businesses and schools are using network to communicate. Most of the users connect their computers to wireless to access network when they are outside. Home networks usually are small, existing within a single structure. Business and school networks can be small, such as in a room or building or widespread, connecting computers across a city, or the global. The world's largest computer networking is the Internet.
Network topology is defined as the interconnection of the various elements of a computer network. Network Topologies can be physical or logical. Physical Topology means the physical design of a network including the devices, location and cable installation. Logical topology refers to the fact that how data actually transfers in a network as opposed to its physical design.
Topology can be considered as a virtual shape or structure of a network. This shape actually does not correspond to the actual physical design of the devices on the computer network. The computers on the home network can be arranged in a circle shape but it does not necessarily mean that it presents a ring topology.
Any particular network topology is determined only by the graphical mapping of the configuration of physical and/or logical connections between nodes. The study of network topology uses graph theory. Distances between nodes, physical interconnections, transmission rates, and/or signal types may differ in two networks and yet their topologies may be identical.
A Local Area Network (LAN) is one example of a network that exhibits both a physical topology and a logical topology. Any given node in the LAN has one or more links to one or more nodes in the network and the mapping of these links and nodes in a graph results in a geometrical shape that may be used to describe the physical topology of the network. Likewise, the mapping of the data flow between the nodes in the network determines the logical topology of the network. The physical and logical topologies may or may not be identical in any particular network.
Figure 1- bus topology
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Figure 1 showing bus topology. A bus network, like the bus of a computer itself, is a single conduit to which I the network nodes and peripheral devices are attached (see Figure 1). Nodes on one type of bus network, Ethernet, transmit data at any time, of any data being sent by other nodes. If one set of data happens to collide with another set of data transmitted by other nodes--that is, if two nodes try to send data at the same time--each node waits a small, random amount of time and then attempts to retransmit the data.
Although the bus topology is one of the most common, it has inherent disadvantages. Keeping data transmissions from colliding requires extra circuitry and software, and a broken connection can bring down all or part of the network, rendering it inoperable so that users cannot share data and peripherals until the connection is repaired.
Figure 2- Star topology
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Figure 2 showing start topology. In local area networks with a star topology, each network host is connected to a central hub. In contrast to the bus topology, the star topology connects each node to the hub with a point-to-point connection. All traffic that transverses the network passes through the central hub. The hub acts as a signal booster or repeater. The star topology is considered the easiest topology to design and implement. An advantage of the star topology is the simplicity of adding additional nodes. The primary disadvantage of the star topology is that the hub represents a single point of failure. In the previous two topologies, the systems in the network were connected to each other. In the star topology, instead of being connected to each other, the systems are now connected to some central device, as seen in Figure 2. In the star topology, one of the biggest advantages is that when one system goes down, it does not bring the rest of the network down with it as it does in the bus or ring topologies.
Figure 3- Ring topology
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Figure 3 showing ring topology. A ring network is a network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node a ring. Data travels from node to node, with each node along the way handling every packet.
Because a ring topology provides only one pathway between any two nodes, ring networks may be disrupted by the failure of a single link. A node failure or cable break might isolate every node attached to the ring. FDDI networks overcome this vulnerability by sending data on a clockwise and a counter clockwise ring: in the event of a break data is wrapped back onto the complementary ring before it reaches the end of the cable, maintaining a path to every node along the resulting "C-Ring". 802.5 networks -- also known as IBM Token Ring networks -- avoid the weakness of a ring topology altogether: they actually use a star topology at the physical layer and a Multistation Access Unit (MAU) to imitate a ring at the data link layer.
Figure 4- mesh topology
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Figure 4 showing mesh topology. In most practical networks that are based upon the physical partially connected mesh topology, all of the data that is transmitted between nodes in the network takes the shortest path between nodes, except in the case of a failure or break in one of the links, in which case the data takes an alternative path to the destination. This requires that the nodes of the network possess some type of logical 'routing' algorithm to determine the correct path to use at any particular time. The mesh topology is the last topology we discuss. In this layout, every system is connected to every other system. The main advantage of this topology is high availability. The main disadvantage of this topology is cost, both administrative and physical. Because each system is connected to each other, the amount of cabling and maintenance necessary can be prohibitive, especially in larger networks. The formula for determining the amount of cable needed in a mesh network is: (N x (N - 1))/2, where N is the number of systems to be interconnected. In example in Figure 4, we have six systems that require 15 cables to create a mesh network. This topology is mainly used in Wide Area Network environments or in environments where high availability outweighs the costs associated with this amount of interconnection.
Figure 5- Tree topology
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Figure 5 is showing tree topology. Tree are also known as a hierarchical network.The type of network topology in which a central 'root' node (the top level of the hierarchy) is connected to one or more other nodes that are one level lower in the hierarchy (i.e., the second level) with a point-to-point link between each of the second level nodes and the top level central 'root' node, while each of the second level nodes that are connected to the top level central 'root' node will also have one or more other nodes that are one level lower in the hierarchy (i.e., the third level) connected to it, also with a point-to-point link, the top level central 'root' node being the only node that has no other node above it in the hierarchy (The hierarchy of the tree is symmetrical.) Each node in the network having a specific fixed number, of nodes connected to it at the next lower level in the hierarchy, the number, being referred to as the 'branching factor' of the hierarchical tree.
Computer communication, it seems will become a much more useful networking tool when large numbers of people with similar interests acquire access to the technology. Though it can expedite the formation of new interpersonal networks by overcoming the space and time barriers faced by traditional networking techniques, it still requires a great deal of concentrated effort and resources to get the people to use it. Computers are important to us because it allows us to communicate with other people easily.