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Class Four: The Internet

I. What Is the Internet?

Back in the early 60's, a young boy named Al Gore had absolutely nothing to do with inventing the Internet. Meanwhile, Paul Baran, a researcher at the Rand Corporation, was working on the problem of how to maintain military communications in the event of a nuclear war. The solution he came up with was a technology called packet switching, in which messages are divided into packets which include information about their route and destination, so that they can be switched from computer to computer along any pathway that leads to the final address. The first packet switching network was set up at the National Physical Lab in 1968. One year later, the Advanced Research Projects Agency, or ARPA, a part of the U.S. military, used the technology to establish ARPANET, the forerunner of the Internet, linking computers at UCLA, Stanford, University of California at Santa Barbara and the University of Utah at Salt Lake City.

During the seventies, ARPANET grew, and other independent networks were also formed. Internet e-mail was invented in 1972, and Usenet began in 1979. ARPA came up with a standard protocol for addressing packets call TCP/ IP (Transfer Control Protocol/Internet Protocol), which allowed the various networks to be linked together. ARPANET changed over to TCP /IP on January 1^st, 1983, which is considered the birth date of the Internet.

In 1986, the National Science Foundation set up a new backbone called NSFnet, and within a year the Internet had expanded from 1,000 to 10,000 computers. Two years later it had reached 100,000 and 3 years after that, in 1992, the year a physicist at CERN in Switzerland named Tim Berners-Lee invented the world wide web, it reached over 1,000,000.

Today, no one can even estimate the number of computers that make up the Internet. Some recent guesses I have seen quoted are that the number of sites in increasing by about a million a day and the number of individual pages by twenty-five per second.

Over time, the component technologies of the Internet have changed; today, there are three major parts: e-mail, Usenet, and the world wide web. I will go over each of these parts, after discussing how to connect to the Net.

II. Connecting to the Internet

A. Hardware

1. Most individual connections to the Internet are dial up connections through the telephone lines. To connect two computers over an ordinary phone line, each one must have a device called a modulator-demodulator, or modem, which converts digital signals from the computer to analog signals which travel over the phone line, and that converts these analog signals back to digital at the other end.

The speed of modems has increased from 2.4 kilobits per second to 9.6, 14.4, 28.8, and 33.6, to the current standard of 56 kilobits per second. 56 kilobits per second is the technological limit for analog modems, and in fact there's a legal limit of 53 kilobits per second. Two modems will connect at the speed of the slower modem, at most, and noise on the phone line will generally reduce the connection speed even more. In reality, anything from 48 kilobits per second on up can be considered a good connection; if your connection is frequently lower than that you should have your phone line checked..

Note that modem speeds are in kilobits, not Kilobytes, so a connection speed of 48 kilobits means you can download a file (theoretically) at 6KB per second. In practice, anything over 4KB per second is a pretty good rate given the noisy phone lines. (Correctly, kilobits are abbreviated Kb, kilobytes are abbreviated KB, but not everyone uses these consistently.)

2. Two faster types of phone-line connection, which are digital rather than analog, are ISDN (Integrated Services Digital Network) and DSL (Digital Subscriber Lines). Both are more expensive than ordinary phone service, and require more expensive hardware as well (often called modems, although technically they aren't, since the signal remains digital.) ISDN is an older technology available in most places and tops out at 128 kilobits per second. DSL is much faster - the speed depends on the type, of which there are several - but it is not yet available in all areas. ISDN is typically a dial-up connection, while DSL is usually a permanent connection (you are always connected when your computer is on.)

3. Another fast (high bandwidth) type of connection uses cable TV lines rather than phone lines. Prices and speeds vary, but it is not all that expensive, if you're already paying for cable TV service. With cable, the connection is permanent.

4. A fourth type of connection is with a satellite dish. This is quite expensive, but download speeds are very high. With most types you still need a regular modem to carry the upline information, since you can't transmit to the satellite but only receive. Two-way satellite service is newer, but becoming available. Satellite connections are available almost anywhere, provided you can see most of the sky, and are the only choice in remoter rural areas..

5. Most large businesses use leased lines such as T1, T3, T5 and so forth. These are extremely fast but cost thousands of dollars a month.

6. A new technology just coming out is wireless broadband. This uses the same 802.11 standard which is used by wireless networks within an enterprise. There is an initial cost for the antenna and installation, but otherwise it is no more expensive than cable or DSL. It is also a permanent connection.

B. Once you have the hardware, you need an Internet service provider (ISP). This is a company which provides access to the Internet. There's usually a range of different payment plans, which may include limited access such as e-mail only, a limited number of hours for a flat fee plus a per hour charge beyond that, and a flat fee unlimited access plan.

You can only access the web at the speed and with the technology your ISP supports, so if you use a high bandwidth connection, your choice will be limited.

For ordinary 56k connections, there are three types of ISP: local, national or regional, and online services. (Online services are companies which offer their own special content as well as access to the rest of the Internet. The best-known are America Online (AOL) and Microsoft Network(MSN).)

Advantages to using a local ISP are that it will be a local call, that they will usually offer more personalized support, and that they will often be easier to connect to. Disadvantages are that small local companies are more likely to go out of business, that they may have outmoded equipment, and that if you travel outside the local area they will be a toll call to connect to.

Advantages of the national ISP are that they will have local numbers, called points of presence, in most major cities, and that they may be more stable. Disadvantages are poor tech support and often difficulties in connecting or slow connections.

The main reason to use an online service is because you want their extra content; otherwise, they have about the same advantages and disadvantages of the national ISP, only more so.

C. Getting an account

Once you decide on an ISP, you need to set up an account. If you want to use MSN or AOL, the software is probably already on your computer; just double click on the icon, and your modem will dial them up; you just fill in the information they ask for and you're on. With a local ISP, you would call them up and they will send you the instructions and information you need to set it up on your computer. Be sure to save this package, because you will need it if you ever have to reinstall your browser or install some new Internet software. (If you already have a connection, you can sometimes sign up with a new ISP through its web site.)

III. E-mail

E-mail is the first reason most people get online. If e-mail is all you want, you can get a basic e-mail service free from an ad-based service like Juno, although it is very rudimentary (no attachments) and often is a toll call.

Most people get their e-mail account from their ISPs as part of an Internet package. (There is also something called web based e-mail which I will discuss later.)

There are a number of e-mail programs available, both freeware and commercial, but I will concentrate on the program that comes with Windows, Outlook Express (OE). The most popular alternatives for home use are probably Qualcomm's Eudora and the Messenger program which comes as part of the Netscape browser suite. These work basically the same way as OE, except for the names of commands and their location in the menus, so if you learn one you can pick up the others fairly easily.

Whichever you prefer, though, you're better off to choose one and stay with it, so your mail is all in one place. (One consideration is that most of the e-mail viruses and worms are targeted at the Microsoft programs, so Netscape may be a safer choice.)

A. Setting it up

If you use Windows, you have some version of Internet Explorer, including the Outlook Express mail program, already installed, whether you like it or not. It's nonuninstallable, except by installing a newer version. (Actually, there is a way to get rid of it using a program specially designed to remove it, but it is not something the average person will try.)

When you install an e-mail program, or try to check your e-mail in OE for the first time, it will ask you for certain information: your e-mail address, your password, and the names of your POP3 and SMTP servers. This information is in the package you get from your ISP. (Many ISP's give you software which configures your system automatic ally, but it's still a good idea to what the settings are in case you want to change programs or have multiple ISP's.) To change existing settings in OE go to Tools - Accounts - Mail - Properties - Servers.

The POP3 - Post Office Protocol version 3 - server is the computer which handles your incoming mail. The SMTP - Simple Mail Transfer Protocol - is the one which handles your outgoing mail. They may or may not be the same. (Some ISP's may use a newer protocol called IMAP - Internet Mail Access Protocol - instead of POP3, but this is rare for a commercial ISP.)

You'll also get the chance to change the defaults for how you want the program to work. To make changes later, just go to the Tools - Options dialogue and choose an appropriate tab.

B. Receiving E-mail

The interface of your mail program may vary depending on the version of the program and how you have customized it, but one standard interface has three panes: the top pane has a list of your mail messages, with the unread ones in bold type, the bottom (preview) pane is where you read the message, and the narrower pane on the left has the folders you can move them to. Assuming you're all set up and using OE, to get your mail you click on Send/Recv. To read a message, just click its name in the top pane and read it in the bottom one.

You can add folders to the left pane by going to File - Folder - New. You should have at least a "Saved Messages" folder for things you want to keep. If you don't get a lot of e-mail and don't subscribe to lists, that may be all you need. On the other hand, I have a whole hierarchy of folders. You can drag and drop your messages to a folder, or to Deleted Items to delete them. (Of course you can also use the delete key or right click, delete.) The Deleted Items folder works just like Recycle Bin; the messages aren't really gone until you go to Edit - Empty Deleted Items Folder. (When you do this, they do not go to the Recycle Bin.)

To read old messages, just click on whichever folder you saved them in, in the left pane. To see the new ones again, go back to Inbox.

To open an attachment (any type of file which is sent by e-mail), click on the paper clip icon or the name of the attachment.

Remember:

Don't open attachments from people you don't know. Don't open attachments from people you do know, unless it's mentioned in the text of the e-mail and you know what it is. If you have any doubt, e-mail the person back and ask what the attachment is. Be especially skeptical of any attachment with the extension .exe. These are programs, and no one is going to e-mail you a program out of the blue. It's probably a worm or a trojan horse (these terms will be explained later).

You can only open an attachment if you have the program to read that type of file. There are programs available that read (but can't generally edit) large numbers of formats; the prices depend on how many types they can read.

C. Sending Mail

To send an e-mail, click on Create Mail. A box will open for you to type. Type in the address(es) in the To: field, or use the Address book feature by clicking the Address Book button next to the box or going to Tools - Address Book. You can also type or use the address book to add names in the Copy (Cc:) and Blind Copy (Bcc:) fields. (If there is no Blind Copy box visible, go to the View menu and click All Headers.) If you use Copy, all the addresses you send to will be visible to each recipient - and some may not be happy about having their addresses shared. With Blind Copy, no one sees the other recipients' addresses.Put a subject in the subject field, and then type the message in the big box. Click the Attach icon (with the paper clip) or go to Insert - File Attachment to add an attached file, and type in the path or browse to the file and click on it. (Remember: only send files as attachments if you know the person you are sending them to can read that type of file.) When you are all done, hit the Send/Recv button.

D. Lists

One source of information on the Internet is e-mail lists. The way that they work is that you subscribe to a list, and then any message any subscriber e-mails (posts) to the list is automatically mailed to everyone on the list. There are two types of lists, Listserv lists and Majordomo lists.

Listserv is much more common. To subscribe to a listserv list, you send an e-mail to listserv@domain (where domain is whatever the last part of the list's e-mail address is) saying Subscribe listname yourname. You may get an e-mail back asking for you to reply, to confirm your address. After you do that, you will get another e-mail which contains the instructions for unsubscribing and any other basic commands that are supported by that list. You should save this message for future reference.

Remember that any list commands, such as subscribe or signoff, go to the listserv, while messages go to the list.

E. Filters

If you subscribe to a busy list, you don't want the messages on the list mixed in with your regular e-mail. And you probably don't want to see junkmail advertising (spam) at all. So you can set up filters in your mail program to sort the messages into folders. To set up filters go to Tools - Message Rules - Mail. You can set up filters to move a file into a folder (say for your lists) or to delete it (for spam) based on the sender, the recipient (on a list, the recipient is the name of the list, not your name), the subject, phrases in the body of the message (make millions of dollars, this is perfectly legal, prestigious nonaccredited universities, etc.), and other characteristics of the e-mail. The filters will be applied, in the order they are set up, to the messages as they come into your computer.

IV. UseNet

One of the oldest technologies on the Internet, the UseNet discussion groups are the successors to the old pre-Internet bulletin boards. The way they work is that people post messages (similar to sending e-mail) to the group, and other people can read them and reply to them.

You can read and post to UseNet groups with OE, but it is much easier with a dedicated newsreader program. There are several good ones which are free, such as News Express and Free Agent.

When you install a newsreader, or when you try to read news for the first time in OE, it will ask you for the name of your NNTP (Network News Transfer Protocol) server. This is in the package from your ISP; often it will not be your ISP, but your ISP's ISP or some other place with a more powerful computer.

Which groups you can get depends on your ISP; The best ISP's for news carry about 40,000 groups in dozens of languages. The groups range from technical discussions in physics and astronomy (remember the origin of the Internet as connecting research groups at Universities), discussions of politics, health, sports and movies, to places where you can get clipart, fonts, computer advice, and of course, hundreds of porno groups. Other ISP's may carry less or not offer news at all.

V. The World Wide Web

Most people, when they think of the Internet, are thinking of the World Wide Web. The Web consists of information-and misinformation-contained in trillions of documents called web pages, stored on millions of different computers, and all linked to one another by hyperlinks.

The format which is used by most web pages is called Hypertext Markup Language (HTML). Although beyond the scope of this class, HTML is fairly easy to learn. Many Adult Ed Departments offer courses in it from time to time, and there are many simple books on the subject.

HTML files are downloaded using the Hypertext Transfer Protocol (http) and displayed by a program called a web browser. There are, or have been historically, two "major" browsers, Microsoft's Internet Explorer and Netscape's Navigator (available by itself or as part of Communicator). At one time, they competed very strongly, to the advantage of the user, but in the last few years, IE, thanks to its incorporation in Windows, and Microsoft's pushing of non-standard "extensions" of HTML that only work with IE, has made Netscape a minority browser except for non-Windows operating systems. Like the associated e-mail programs, both are very similar except for names and locations. This class will assume you are using a recent version (4.0-6.0) of Inaternet Explorer. A third browser, called Opera, takes up less space on your hard disk and is therefore a good choice for people with older computers. It also follows the official rules more closely than the other two.

A Note on Addresses

Every computer on the web has a unique identification number called an IP (Internet Protocol) address. This is four numbers between 0 and 255 separated by periods. If you type this number into the Location box of your browser, you will connect directly to the site. Hardly anyone does this regularly anymore, except Jason Fox, because the numbers are not easy to remember for hundreds or thousands of sites. Instead, there are human-readable names for each website, called Universal Resource Locators (URLs).

As an example, the URL for the Friends of the Skowhegan Free PublicLibrary site is http://www.friendsofmainelibraries.org/organizations/fosfpl

The http:// is called the scheme; it just means use the hypertext transfer protocol. (This will be the same for any HTML web page, except that some sites use https://, which stands for http secure and means that they use encryption.) You don't normally have to type this unless you're using a very old browser; the newer ones just add it by default.

The part between the // and the first / is called the host name. The part of the host name before the first period (www in the example) is just the name of the computer the page is on; it can be anything at all, but usually it is www. The second part (friendsofmainelibraries in the example) is the domain name; this tells whose computer it is, and these must be registered with the appropriate agency. The last part is the top-level domain, which is a kind of classification: the original six were .com (commercial), .edu (academic), .gov (government agencies), .net (networks), .org (organizations), and .mil (military). Some additional top-level domains have recently been added, as the original six are becoming saturated (especially .com). In place of (or in addition to) the top-level domain, there can be a two letter country code. The .us is seldom used, as most web sites are in the U.S. anyway, but you will often see .ca (Canada), .uk (United Kingdom), .jp (Japan), .fr (France), .it (Italy), etc. Not all are obvious unless you know the name of the country in its own language, e.g. .de (Germany) or .ch (Switzerland). There are also state codes, which must be followed by the .us - for instance, .ca.us is California, but .ca is Canada, and .de.us is Delaware, but .de is Germany.

The remainder (after the first /) is the path to the actual HTML file on the host computer; this is the same as the path to a file on your own computer except that it uses / instead of \. The last item in the path will be the actual HTML file with the extension .htm or .html. (If there is no file given, as in the example, the computer goes to a default page named index.htm, home.htm or default.htm, depending on how the server is set up.)

When you set up your Internet connection, you have to type in two numbers called the primary and secondary DNS (Domain Name Server.) These numbers are found in the package from your ISP, and they are IP addresses. When you type a URL in your location box, or click on a link that uses a URL, the browser goes to the DNS, a big computer somewhere, and looks up the actual IP address for that URL. The browser then uses that IP address to find the page on the Internet.

[Demonstration of hotlinks, back and forward button, etc.]