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The Internet via Cable
Warm-up: What means of transmitting information do you know? Put them in chronological order: oral messages, letters... What are the latest achievements?
Using cable Internet services for the first time can be a breathtaking experience. Images and text flash before your eyes instantly. Full-motion video and audio play without jitter. Whoa you see this, you realize that this was how the Internet was meant to be. Even for Internet old-timers, it's like a whole new world.
The cable television network has emerged as the early leader in providing such high-speed data access in the home. With more than a million cable modem subscribers now in North America, the system has matured from a string of experimental deployments in 1995 to a main-stream service available in most major cities.
Internet access over cable runs at speeds up to 100 times those of the traditional dial-up world. And the connection is "always on", enabling users to call up a site immediately as the spirit moves them. Gone are the days of having to log in to the network. How does cable achieve these data rates? In the late 1980s and early 1990s cable operators started deploying fiber optics in their networks. Cable companies ran fiber out to individual neighborhoods and made use of the existing network of coaxial cable - the familiar line that screws into your TV - to reach the "last mile" to each home. The optical fibers connect the cable operator's central facility (the "head end") to each neighborhood area (the "node"), which typically encompasses about 1,000 homes, each a potential customer. Fiber has greatly increased the capacity and cable TV networks. With a cable Internet connection, data occupy the space of one TV channel. Tune to this channel with your TV, and you'll see only static, but connected to your cable modem it becomes a data stream flowing at about 40 mega-bits per second, which can then be relayed to your personal computer at rates up to 10 megabits per second. The fiber network also allows signals to be sent back from the home to the head end, making telephone and interactive video services possible. About half of all North American cable homes already have this two-way capability, fewer in Europe and Asia.
A cable modem can connect to more than one PC in the home, with excellent support for in- home networks. Cable modems use a number of advanced techniques to perform their duties. In fact, "cable modem" is a bit of a misnomer, because it has several additional roles: directing traffic, encrypting for security, validating signals and tuning the proper channel. Automated software updates for the modems can be centrally coordinated, and service anomalies can be flagged without human intervention. Early-warning signals from the modems let the provider respond to problems before they affect service.
Cable modems will enable a wide variety of services. But what really thrills television executives is the integration of TV with the Internet allowing subscribers to move back and forth seamlessly, from one medium to the other. For instance, while you're watching a film you could have a window open on your TV for chatting with other viewers about what's happening on the screen. And someday soon images, sounds and data from all over the globe may come at you at remarkable rates, and you will realize that what you're experiencing is not your fathers cableTF network. By MiloMedin and Jay Rolls from 'Scientific American1, October 1999
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What is an E-Mail?
The most frequently used function of the Internet is e-mail. It is probably the easiest of the functions to learn to use effectively. E-mail provides almost instant communication with others on the system worldwide. With e-mail you never get a busy signal. The message arrives at a computer and waits for the receiver to respond.
In order to use e-mail each user must have their own unique user name. The way user names are formed is decided by each institution. For example at Concordia all user names begin with the prefix CRF, then we use the first six letters of our last name and our first and middle initials. The user name is followed by an @ sign. Following the @ will be the node, domain and type names. Each node will also have an unique name. Each organization decides its own node and domain names. There are several different type names, which are standard: Commercial = com; Educational ~ edu; Government - gov; Military = mil; Organization = org.
Many people now include their e-mail address when sending standard communications,, What is very nice about the Internet is that as soon as you send a message your address is automatically placed at the top of the message so the receiver knows who sent it. Ifs an automatic return address. You can usually figure out where someone's message is coming from by looking at the node and domain names. For very good reasons some organizations have unusual domain names and determining the origin of the message is more difficult. Northwestern University, for example, uses CASBAH as its domain name and the University of Virginia uses DAYHOFF. Making the connection: The first thing you do is to log into уодг system. Once you have logged in you may enter the mail system. There are many different mail software packages available. Current e-mail software is getting easier to use with each new version. Some are menu driven and others require you to know and type the command. There are other things you can do with e-mail List serves provide a discussion forum for people with similar interests. You can gain access to these forums by subscribing. Simply send an e-тщ! message to tb address given for the listserv and ask to be added to the subscription list. Sometimes a given e-mail address doesn't work. When that occurs, there are two possibilities. One is that the address has changed. Remember, thai the Internet changes from day to day, and so do its addresses. You need t remain very flexible when you work with list serves. The second possibility is that it may be necessary to use a gateway to get into listserv. A gateway is a computer that connects two types of networks an automatically converts the protocol used in those networks. Newsgroup are also available on some systems. They are like reading a newspaper every day. Newsgroups require special software to read the messages.
