Teenagers can do homework and research on tablet computers they carry in their backpacks Thanks to the Internet teenagers in the year 2015 and beyond are constantly connected not only to friends and family but also to people and information worldwide They can store much of their lives in the cloud to be retrieved by anyone at any time They can take a photo and send it to friends order a pizza download music and movies find a location check the weather or watch a football game all with pocket sized smartphones But many technological advances occurred between those first steps in the 1960s and the Internet of today 10
TRACING THE INTERNET Technology writer Andrew Blum started with only a vague notion of the Internet To be online was to be disembodied reduced to eyes and fingertips he said There was the virtual world and the physical world cyberspace and real places and never the two shall meet Blum's view of the Internet changed radically when his own portion of it failed The technician sent to solve the problem tested electronic cables and switches and eventually he traced the problem outdoors to a squirrel chewing through the rubber coating on a wire which in turn was attached to a metal box on a pole Suddenly Blum realized the Internet did not exist in a cloud It consisted of physical structures cords wires and boxes all of which led somewhere The Internet is a vast electronic communication network that connects many smaller networks around the world In other words it is a global network connecting millions of computers in more than 100 countries But what exactly does the Internet consist of It is vastly more complex than its creators could have imagined People use it constantly but few stop to consider its components A teenager gets onto the Internet accesses a browser and pulls up his or her Instagram Where did the page come from How did it get from its source to the computer Where is it stored when no one is using it A girl sends a text to her mother who is on a business trip on the other side of the country How does the text travel from her cell phone to her mother's Out of millions of cell phones in that distant city how does the text pinpoint only her mother's phone
How the Internet Sends Messages The purpose of the Internet is to send messages billions and billions of them Some are simple text messages Others are encyclopedic amounts of information on every topic imaginable Some are photographs videos or movies Others are maps blueprints financial information or military codes All of this information must be broken down into digital code codes composed of ones and zeroes This digital information travels from the building where it originates through a series of tubes buried along roads and railroad tracks across the bottom of the ocean and on to other buildings around the world Its travel is anything but random Each tiny packet of information is labeled with its own unique address and its destination's unique address The information is sent from a single router today's equivalent of an IMP to nearby routers which then transfer it to routers near them In this way the unique packet of information reaches around the world Billions of information packets zip past continually each one uniquely labeled to be decoded at its destination Physically the tubes contain fiber optic cables bundles of glass strands each as thin as a human hair These cables carry digital information in the form of light across very long distances Computers at the beginning and end of the data transmission have components called transducers which transform the data from digital data to light and back Fiber optic cables transmit information for the Internet telephone systems and cable television 12
