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WWW Clients

You will likely first experience the World Wide Web through a WWW client. In WWW terms, these are called browsers. Browsers are available for almost all major computer platforms, however you also need the appropriate network infrastructure to make them work.
Network Infrastructure

What browser you use depends largely on how you are connected to the Internet. If you are using a terminal emulator and a serial connection, you will most likely use a character-mode browser. If you can send network packets from your computer to the Internet, you will probably use a graphical-mode browser.

Character-Mode Browsers

A popular character-mode browser is Lynx. You cannot use Lynx to display graphical images, but it does support forms, as well as all HTML 2.0.

Graphical Browsers

Three popular graphical browsers are Mosaic , Netscape and Microsoft Internet Explorer.

Mosaic and Netscape are available for Microsoft Windows, X-Windows, and the Macintosh, while Microsoft's IE is only available for Microsoft Windows. Mosaic and Microsoft IE are free to anyone; Netscape is free to any not-for-profit institution.

Network Infrastructure

How you connect to the Internet affects how you view the WWW. If you connect via a modem, you won't be able to view large WWW pages, images, sounds, or video; if you have a T1 connection (1.544M bits/second), you will be able to enjoy these features. Some WWW pages assume that you have a fast connection to the Internet.

Local Area Networks

If your Local Area Network has a gateway to the Internet (there are several different methods to do this), you should be able to use a graphical browser on your own workstation to cruise the WWW. If you are using a PC with Microsoft Windows, you'll need to have a Winsock interface installed (in addition to the regular networking configuration). Macintosh users already have network support via MacTCP. UNIX workstation users should also have built-in support for networking.

Dial-in Access

There are two methods of dialing into a machine to get access to the Internet. If you dial in and log on as usual (on UNIX you see "login:" and shell prompt or on MPE you type "HELLO" and get a colon prompt), your computer is not directly connected to the Internet, so it cannot send network packets from your PC to the Internet. In this case, you will have to use Lynx to access the WWW.

If you dial-in using SLIP (Serial Line IP) or PPP (Point-to-Point Protocol), your computer becomes part of the Internet, which means it can send network packets to and from the Internet. In this case, you can use graphical browsers like Mosaic or Netscape to access the WWW. The Internet Adapter is supposed to allow users with only shell account access to obtain a SLIP connection. Shiva and Livingston provide products that allow users to dial into hosts using SLIP or PPP.

Character-Mode Browsers

While Lynx is not the only character-mode browser, it is one of the most powerful. Lynx is available for many platforms. You can obtain a pre-compiled version of Lynx for MPE/iX from Some users are disappointed that Lynx's display is limited to text. What Lynx does demonstrate is that a single server can provide information to both character-mode and graphical clients. Still, to gain a full understanding of how powerful the client/server concept can be, you should compare Lynx's capabilities to the capabilities of graphical browsers such as Mosaic or Netscape.

Graphical Browsers

Mosaic is one of the tools that makes the WWW so popular. With Mosaic, you can view in-line graphical images surrounded by proportional font text in multiple colors. For an excellent introduction to Mosaic, see the O'Reilly book The Mosaic Handbook. Three versions of the book are available (Windows, Macintosh, and X-Windows). The PC version of Mosaic requires the Win32s subsystem which is described in the Mosaic readme file.

While Mosaic is popular, the newer Netscape browser is even more appealing, especially when used with slower network connections. Earlier versions of Mosaic did not display anything until an entire URL (and its associated graphical images) had been downloaded. Netscape, by contrast, starts displaying as soon as a screenful of information is available. As you page down through a document, Netscape barely pauses as it continues to download the URL in the background.

The newest graphical browser is the Microsoft Internet Explorer. This browser is part of Microsoft's strategy to make the Internet an important part of all Microsoft products. Like Netscape, the Microsoft IE also does background network transfers. We perfer Netscape over Microsoft IE, due to Netscape's user interface and better reliability.

External Viewers

Neither Mosaic nor Netscape tries to handle all the data that can potentially be served up on the Web. They both understand HTML, in-line graphics, and URLs. Netscape can display external GIF (Graphics Interchange Format) files, but Mosaic cannot. To view images, listen to sound, watch movies, or view spread sheets, you must have external tools to support these data formats. For Microsoft Windows users, a popular graphical viewer is LView. The Mosaic Handbook provides a good introduction to the external tools that you need to support full multimedia applications. Most of these tools also work with Netscape.