9 Apr 1995
Network Navigation
When you are looking for information in a reference book, you might go to the table of
contents (that lists topics) or to the index (organized by keywords). One book may refer
to information in another book through a footnote. Researchers often copy information from
a book onto index cards arranged by a private system. In the same way, information on the
Internet is organized under a variety of navigational aids.
- FTP (File Transfer Protocol)- A utility to transfer a file if you know the name
of the computer where it is located and the name of the file. This is the oldest and
simplest of the Internet protocols. Some computers only allow FTP access if you have an
account on the system. However, the Internet has a large number of large, important file
servers that allow "anonymous" FTP from anyone in the network.
- Gopher - Gopher organizes data into a series of menus. Each menu presents a list
of item. Each item is either another menu or a file. Under the covers, each menu item is
accompanied by control information that identifies to the Gopher program the name of the
computer that holds the item and an identification string (usually the file name) used to
fetch the menu or file. The menus on one Gopher server can point to items on other servers
around the world. Different Gopher servers can organize data based on different subjects.
For example, the current weather report for New Haven can be found on a Gopher service
dedicated to weather (under the Connecticut menu under the US States menu), but it can
also be found in the Yale Campus Gopher (as an item of local interest). Gopher servers can
be run on Unix machines, or on PCs running OS/2 or Windows NT. Any organization with a
machine can mount a series of menus on any subject, and can freely reference other Gopher
servers around the world. YALEINFO (the Yale Campus Information bulletin board) is based
on a Gopher server.
- WWW - The World Wide Web has come to public attention due to favorable articles
about the Mosaic program. In fact, the Web is often mislabeled as the Mosaic system (much
to the annoyance of all the other groups with Web programs). More precisely, the Web is a
collection of interlinked documents available through the network. The Web doesn't compete
with other protocols, it digests them. A Web tool knows how to use the FTP and Gopher
protocol, and Web documents can point to files and menus supported by those systems.
However, a Web document has much greater visual impact because it can contain formatted
text (headers, italics) and images (pictures, diagrams, icons, and
"letterheads"). Documents in the Web are linked together when a word or picture
is displayed with highlighting or a special frame. Click the mouse on this link, and an
associated document is fetched from a network server, formatted, and displayed. The Web
organizes information through what are essentially an active version of footnotes.
- WAIS - Large groups of documents are indexed by keywords. WAIS servers specialize
in a subject, such as "poetry" or "film reviews." The user selects a
set of topic-servers and one or more keywords. The network returns a list of possible
documents each of which can be retrieved on demand. WAIS operates like an automated Index.
The computer can speed some things up, but it does not create new ways of thinking.
Books have long been organized or accessed though Contents, Index, or Footnotes.
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Copyright 1995 PC Lube and Tune -- Windows on the
World -- H. Gilbert