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1995-02-10
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Date: Wed, 8 Feb 1995 11:16:47 -0600
From: BITNET list server at UA1VM (1.8a) <LISTSERV@UA1VM.UA.EDU>
Subject: File: "MAP24 LESSON"
MAP24: WWW (PART TWO)
"I love to sail forbidden seas, and land on barbarous coasts."
-- Herman Melville, Moby-Dick
Back to work.
Yesterday I told you that "URLs" is pronounced "earls." In fact, a lot
of people still use the initials and call them "U-R-Ls." I personally
prefer calling them "earls" because "earls" rhymes with "squirrels,"
but the choice of what you call them is completely up to you :)
Let's take a look at how a sample WWW browser works. There are three
basic types of WWW browsers available: line-mode browsers, full screen
browsers (like Lynx), and graphical browsers (like Mosaic).
Line-mode browsers are about as user un-friendly as you can get.
This is hard to describe, but line-mode browsers work a little
like FTP inasmuch as you type a command, get some information
on your screen, type a new command, get some more information, and
so on ...
A full screen browser puts a menu on your screen that looks a little like
the Gopher menus that we saw last week. You move the cursor up and down
the screen, select a highlighted link, press enter or return, and you
are automatically taken to a new document or file (your fill screen
browser may work differently than this, though).
Graphical browsers allow you to access not only text, but also pictures
and sound (a.k.a. "hypermedia"). In fact, these pictures can be put in Web
documents (a.k.a. Web pages), making that Web page look less like a
Gopher menu and more like a page from a color magazine! Most graphical
browsers use a mouse, and you point-and-click on a highlighted link to
access it.
The URL for the sample Web page that we are going to use today is
http://ua1vm.ua.edu/~vmhttpd/index.html
and I am going to be using the UF WWW Browser for CMS to access this
page. I'll talk a little more about how you can access a WWW browser
in a few minutes, but I first want to show you what a basic Web page
looks like.
The UF WWW Browser for CMS is the browser that my service provider
uses, and it is a full screen browser. The browser that you use -- if
you can even access a WWW browser -- will probably look and work a
little differently than what you will see in this example.
Finally, in real life my browser highlights the links by making them
a different color than the rest of the text. There is no way for me to
use different colors in this letter, so I have highlighted the links
in this example by surrounding them with a (* *).
Just like I can access an item in a Gopher menu by pointing at it and
selecting it, I can access a WWW link by pointing at it and selecting
it.
Enough talk. Time for the example.
I access my provider's WWW browser, and the following appears on my
screen:
Albert 1.2.0 (UF WWW Browser for CMS) Screen 1 of 2 (more screens)
Viewing=http://ua1vm.ua.edu/~vmhttpd/index.html
Title=UA1VM WWW Home Page
Welcome to The University of Alabama's CMS WWW Server
This CMS server is still under development. Any (*comments*)
or (*suggestions*) will be greatly appreciated. Thank you.
Gopher Sites:
- (*UA1VM CMS Gopher Server*)
- (*UA1IX AIX/370 Gopher Server*)
- (*RISC/6000 Gopher Server*)
- (*RICEVM1 CMS Gopher Server*)
Telnet Sessions:
- (*UA1VM.UA.EDU*)
- (*UA1IX.UA.EDU - Line Mode*)
- (*RISC.UA.EDU - Line Mode*)
WWW Sites:
- The University of Alabama Libraries (*WWW*)
- The University of Illinois at Urbana-Champaign (*WWW*)
- The Alabama Supercomputer Network (*WWW*)
- NASA Information Services via (*WWW*)
Leisure:
- (*Intertext Magazine*) - Electronic Fictional Magazine at The
University of Michigan
- (*Wiretap*) - a gopher to Cupertino, California
- (*NNR*) - UA1VM's Network News Reader
Other Neat Stuff:
- The University of Alabama Library's On-Line (*Card Catalog*)
- a (*map*) of The University of Alabama campus
... snip snip snip ...
COOL!
I can select any of these links -- the words set apart from the rest
of the text with a (* *) -- and be transported to that particular link.
From this one Web page, I can access Gopher, telnet, and even other
Web pages! (I can also access FTP, although this page does not show
it).
We've seen a lot of Gopher and telnet recently. Let's take a look at
another Web page. Since I used to be a Simulations Director at the
United States Space Camp (did I forget to tell you that?), I'm going
to move my cursor down to the (*WWW*) link next to "NASA Information
Services", press enter, and see what happens:
Albert 1.2.0 (UF WWW Browser for CMS) Screen 1 of 2 (more screens)
Viewing=http://hypatia.gsfc.nasa.gov/NASA_homepage.html
Title=NASA Information Services via World Wide Web
National Aeronautics and Space Administration
NASA Logo
(*World Wide Web (WWW) information services*)
(*Hot Topics*) NASA news and subjects of public interest
(*NASA Strategic Plan*)
(*NASA Strategies, Policies, and Public Affairs*)
(*NASA Online Educational Resources*)
(*NASA Information Sources by Subject*)
... snip snip snip ...
This is certainly more interesting than SURAnet! ;)
From this Web page I can access OTHER Web pages, and from those Web pages
I can access even MORE Web pages, and so on ...
Yesterday I told you that it is possible for you to connect directly
to a specific Internet resource so long as you know the resource's
URL. *HOW* you do that depends on the browser that you use.
For the line-mode browser at CERN, for example, the command to connect
to a particular URL is
GO <URL>
replacing <URL> with the URL of the Internet resource that you want
to access. In Lynx, you just select the "GO" link on the browser's
start-up page; in most graphical browsers (like Mosaic), there is
usually an "Open URL" option in one of the menus. (1)
Before you can do this, however, you have to first access the Web.
There are three ways that you can do this:
1. Through a browser stored on your local Internet service provider's
machine. Ask your provider if your site has a Web browser, and how
you can access it.
2. Through a browser stored on your own machine. Until recently,
you had to have a SLIP or PPP connection to do this. Some
providers -- providers who FLOODED my mailbox when I did
not talk about the special Level 2.0002746278546723 access
that they offer -- now allow you to store a Web browser on
your own machine even though you only have Level 2 access.
If you do not have a SLIP or PPP connection, contact your
provider BEFORE you store a Web reader on your own computer
and double-check that your provider will support the browser.
*MOST* service providers can NOT support a Web browser unless
you have a SLIP or PPP connection.
3. Through a telnet connection to a publicly-accessible Web
browser.
If you have a SLIP or a PPP connection, the WWW FAQ that I have stored on
the University of Alabama's LISTSERV file server (WWW FAQ1) has a list
of FTP sites where you can get specific Web browsers.
(Do me a favor ... re-read that last sentence. Did you EVER think you
would understand a sentence like that? Isn't this workshop COOL?!!)
If you do not have access to a Web browser through your site, you may
still be able to access a Web browser through telnet. The following are
a couple of the public Web sites: (1)
telnet address comments
-------------- -----------------------
info.cern.ch No password is required. This is in
Switzerland, so U.S. users might be
better off using a closer brows