SelFulfillment Articles - Software Issues


What is Router?
by Richa Sinha

A router is a computer networking device that buffers and forwards data packets across an internetwork toward their destinations, through a process known as routing. It is a device that maintains different routes of the network and finds the best route between any two networks, even if there are several networks to traverse.

A router consists of a computer with at least two network interface cards supporting the IP protocol. The router receives packets from each interface via a network interface and forwards the received packets to an appropriate output network interface. Received packets have all link layer protocol headers removed, and transmitted packets have a new link protocol header added prior to transmission.

The first router was created at Stanford University by a staff researcher named William Yeager in January of 1980. His boss at the time told him that he was the "network guy" and to find a way to connect the computers in the computer science department, medical center and department of electrical engineering. He first wrote a network operating system and routing code to run on a DEC PDP11/05. He used Alan Snyder's Portable C compiler but it generated too much code so he modified the compiler to improve the code generators. That still wasn't good enough so he wrote an optimizer for PDP11/05 assembler that reduced the code size further.

The routing occurs at layer 3 (the Network layer) e.g. IP) of the OSI seven-layer protocol stack, where a router acts as a junction between two or more networks to buffer and transfer data packets among them. A router is different from a switch. A switch connects devices to form a Local area network One easy illustration for the different functions of routers and switches is to think of switches as neighborhood streets, and the router as the intersections with the street signs. Each house on the street has an address within a range on the block. In the same way, a switch connects various devices each with their own IP address on a LAN. However, the switch knows nothing about IP addresses except its own management address. Routers connect networks together the way that on-ramps or major intersections connect streets to both highways and freeways, etc. The street signs at the intersection show which way the packets need to flow.

So for example, a router at home connects the Internet Service Provider's network (usually on an Internet address) together with the LAN in the home (typically using a range of private IP addresses, see network address translation) and a single broadcast domain. The switch connects devices together to form the LAN. Sometimes the switch and the router are combined together in one single package sold as a multiple port router.
In order to route packets, a router communicates with other routers using routing protocols and using this information creates and maintains a routing table. The routing table stores the best routes to certain network destinations, the "routing metrics" associated with those routes, and the path to the next hop router. See the routing article for a more detailed discussion of how this works.
Routing is most commonly associated with the Internet Protocol. They are specialized computers that send your messages and those of every other Internet user speeding to their destinations along thousands of pathways.

About the Author

Richa Sinha is associated with Routers Articles. From here you can gather more information on Wireless Routers.





A Breif Histoory Of Video Games
by James Brown

Video games have become a billion dollar industry. They represent both a pastime and a hobby for both adults and children. Retailers have exploited the popularity of video games and now clubs, magazines, conventions and other social events are all offered with a video game theme. T-shirts, backpacks, lunchboxes, and sweatshirts all come printed with video game logos. These are mostly unnecessary, since video game players have uncanny, radar like ability to find each other at parties and turn the conversation into a discussion of video game techniques, graphics, and sound effects.

But it's good to know origins just as a film devotee needs to understand what made Citizen Kane so special, avid video game players may want to know what games were popular in the past.

Many video game authorities (don’t you wonder what they’re like?) cite Spaceman as being the first video game. It appeared in 1964 and was developed by a lone student programmer. Spaceman was a comparatively simple game that pitted two players against each other and armed them with a pair of classic sci-fi rocket ships complete with tiny missiles. The computer mouse controls were limited to thrust, rotate right and rotate left. The game featured an unpredictable hyperspace panic button for emergency situations, but the use of this panic button could have all sorts of effects, some desirable and some not. All action took place on a single screen that featured a sun that exerted a powerful gravitation pull on the combatants. Most players steered clear of this but some intrepid players were able to use the sun's attraction as an asset.

Although it came along in 1972, most people believe that Pong was the first video game developed. Pong' was composed of simple black-and-white visuals, and play consisted of simple back-and-forth table tennis like movements.

Pac Man is probably the most widely known and popular video game of all time. Japanese designed in 1980 in an attempt at a game that would interest girls.

Evidently they decided that eating was something girls enjoyed because they designed a character that looked like a circle with a chomping, wedge-shaped mouth. Pac man was simply a hungry yellow creature who lived in a maze that it proceeded to eat its way through. However, foes 4 colorful globby ghosts lived in this maze as well who existed solely to end Pac Man’s career as an eating machine.

Doom came along in 1994 and engaged the game player in an ultra-violent, blood-soaked battle against the forces of Hell. The game has a sort of amorphic quality since it did nothing to define or represent a hero. The player takes the active role and he is thrown into the middle of the action, with a health indicator at the screen bottom to indicate the games’ progression.

Since then, many video games have been developed to follow this course of blood spilling games with increasing levels of violence. But in 2000, video games turn a surprise u-turn when The Sims came out. Here the game consisted of a sort of Lego virtual reality where the player could build and furnish his or her home. It appealed to the nesting instinct and players created ongoing sagas that revolved around decorating their virtual homes and raising children. The Sims is a wish fulfillment vehicle where the player can create an ideal life and forget his own. It is rumoured that a second version of the game is planned wherein the Sims and their neighborhood cope with falling real estate values when the characters from Desperate Housewives move in.

About the Author

James Browm writes about http://www.videogamesbox.com/





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