Introduction In a Nutshell As soon as you have NCSA Mosaic for the X Window System working (See ÒHow to InstallÓ on pageÊ1Ð1), there is one thing you need to know: To navigate the web of information, single click your left mouse button on the words or images shown in color or underlined, which are the hyperlinks between documents. Mosaic Capabilities NCSA Mosaic software is a distributed hypermedia system designed for information discovery and retrieval over the Internet, which is a global network of networks. NCSA Mosaic provides a single interface to the variety of protocols, data for- mats, and information servers available throughout the Inter- net. NCSA Mosaic includes the following features: ¥ display of plain text, rich text, and hypermedia ¥ inline graphics and images ¥ a customizable graphical user interface ¥ global history of information space navigationÑtracking where youÕve been ¥ quick access to important or frequently used documents via a personal ÒhotlistÓ ¥ search capabilities within a document and over the Inter- net ¥ text and voice annotation for documents anywhere on the Internet ¥ full TCP/IP-based communications support ¥ easily extendable to arbitrary viewers or other data for- mats NCSA Mosaic is implemented for three platforms: Macintosh, Microsoft Windows, and the X Window System on UNIX sys- tems. The Web and Hypermedia The World Wide Web (Web) originated at CERN, the particle physics institute in Geneva, Switzerland. The Web, sometimes abbreviated WWW, is a worldwide hypermedia information space providing ready access to a variety of documents con- tained on servers connected to the Internet. In this case, docu- ment refers to a file of any type (e.g., text, graphic, video) that can be stored on a Web server and viewed by Web client soft- ware. Hypermedia organizes information as an interconnected web of associations rather than as a linear sequence (which you find in a book). Scattered within a hypermedia document are hyperlinks (words or images that are highlighted) to other related documents. Clicking on a hyperlink brings up a new document. In turn, that document links to others, and so it goes. Most documents available on Web servers are linked, meaning that hyperlinks embedded in the documents connect all the documents in some way. For example, NCSA Mosaic documen- tation contains links to documents on the NCSA Web server as well to documents on servers maintained by other universities and research laboratories. Those Web servers have documents that, in turn, link to other documents on other servers. Servers and Clients NCSA Mosaic uses a client/server model. Some computers are configured to communicate with other computers and offer services, such as providing documents or search mechanisms. The machines that provide the services and the document files are called servers. A workstation runs client software, such as NCSA Mosaic for the X Window System, that requests services and provides the interface between the server machine and the user. Together the client and server provide information and the way to access that information. Server software, using the HyperText Transfer Protocol (HTTP), is also available from NCSA. See ÒSystem Configura- tion and Modification AssistanceÓ on pageÊCÐ1 for informa- tion. NCSA Established in 1985 with a National Science Foundation grant, the National Center for Supercomputing Applications (NCSA) opened to the national research community in January 1986. NCSA is a high-performance computing and communications facility designed to serve U.S. computational science and engi- neering communities. Located on the campus of the University of Illinois at Urbana-Champaign (UIUC), NCSA is funded by the National Science Foundation, the Advanced Research Projects Agency, other federal agencies, the state of Illinois, the Univer- sity of Illinois, and industrial partners. NCSA Mosaic Software Developers NCSA Mosaic is a product of the NCSA Software Development Group (SDG). SDG develops workstation software programs to assist in scientific discovery, including software for data anal- ysis and visualization. SDG develops tools for all of the major platforms: Macintoshes, PCs, UNIX workstations, and high-end supercomputers. Most SDG tools are available on the NCSA anonymous FTP server (ftp.ncsa.uiuc.edu). Notational Conventions Material in this manual is presented in text, screen displays, or command-line notation. Different typefaces indicate different functions. New concepts or terms are generally in italic type when they first occur in text to indicate that they are defined in the para- graph. Cross references within this manual usually include the title of the referenced section or chapter enclosed in quotation marks (e.g., see ÒExploring on Your OwnÓ on page 5-4). Boldface type represents characters you enter as shown (lit- eral expressions). Lowercase italic type represents a variable, a placeholder for the text you actually enter. A variable can consist of different characters each time you make the entry. Throughout this manual, you may be instructed to enter spe- cific characters on the keyboard. These entry instructions (command lines) are printed in fixed-width boldface type (e.g., dothis) and appear either within a paragraph or on a separate line. Command lines are normally entered in lowercase. San-serif boldface type (e.g., the Cancel button) represents boxes and buttons in dialog boxes, command names on pull- down menus, menu names, and hyperlinks. Keys that are labeled on your keyboard with more than one character, such as the RETURN key, are identified by all upper- case letters in normal font. Keys that you are to press simulta- neously or in succession are linked with a hyphen (e.g., press SHIFT-OPTION-d).