This lab will only be held Wednesday and Thursday (i.e., not Tuesday) -- you may come to any section. This lab is optional, but is strongly recommended for anyone not familiar with Netscape, the World-Wide Web, and newsgroups (Usenet).
This week's lab covers some of the bare basics of using the computers around campus, such as logging in, using the mouse and windows, and using Netscape to browse the World-Wide Web and use newsgroups.
Index: Lab basics, Log in, Windows, Netscape, News, Email
All labs are held in Ryon 102 (the southwest corner); all will be held in the back section.
Sections:
The labs for Comp210 complement the lecture. The labs focus on providing additional examples and hands-on work to reinforce the lecture.
Also, the labs cover utilitarian details not covered in lecture, such as how to use different software packages and (later in the semester) aspects of C syntax. These topics are important for doing the homework, but would be distracting from the overall flow of the lectures.
There will be weekly lab web pages, but no assignments beyond the homeworks distributed in lecture.
After each weekly lab session, be sure to look over that lab's web page: most of the material will be familiar from lab, but sometimes there isn't enough time in lab to cover every topic. You may be held responsible for knowing any information which is on the lab web pages.
To use the computer, you need to log in, verifying that you have permission to use it and authenticating who you are.
Sit down at a computer in any computer lab on campus (e.g. Ryon 102), and get the login prompt. This prompt should be there when you sit down.
If you don't have an Owlnet account yet, you can apply for one now. Type apply, followed by the Return key. Follow the directions on the screen, and answer the slew of questions. One thing you'll be asked is for your login name; some people think it's cool to have login names like "empress" or "slugface", but be warned that whatever login name you choose, you'll be stuck with it for the rest of your stay at Rice! You'll also be asked for a password (which you can and should change regularly); heed what it says about keeping your password secure. It is a violation of Owlnet policy to give out your password to anybody. Within 24 hours, you should have your Owlnet account; your e-mail address will be yourLoginName@rice.edu.
Assuming you do have an Owlnet account, type your login name, followed by the Return key. Then type your password, followed by the Return key. Note that when you type your password, nothing appears on the screen so that noone can see your password by looking over your shoulder.
When starting with the default Owlnet set-up, you will see two windows on the left-hand side of the screen.
A window displays information about a single program. The lab computers use a system called X Windows, but the basics are similar to those on a Macintosh or PC (using Microsoft Windows).
We will describe the basic behavior of the default Owlnet set-up. (If you want, you can customize X Windows in many ways, including their appearance and their behavior. We will be customizing them a little in the next lab with some course-specific shortcuts. Note that if you don't use the default behaviors, the labbies might not be able to help you as well.)
You will see two window appear on the left of the screen. A window displays information from a program. These particular windows are each an xterm ("X terminal"), each running a Unix shell. Today we will only use one very briefly. Each of these windows has a titlebar and a couple buttons at the top.
The shaded background is considered a window, too, called the root window. Among its special properties is that it doesn't have a titlebar.
First, just play around a bit with the window manager (by default, you use twm):
A wise word from the Owlnet User's Guide: "Leaving your workstation unattended is dangerous to your personal files, your reputation, and to system security. People have taken advantage of such unwary users by erasing their files, sending rude mail to third parties, and setting up ways to do these things again in the future. Obviously, such actions are unacceptable and will be punished; however, punishment of the malicious user comes after the damage is done." If you are going to be away from a workstation for a short period of time, e.g., to go to the restroom, pick up a printout, or talk to a labby, you can lock the workstation. Click with the right button in the root window and choose the Lock Screen option.
When you are done using the computer, it is important you log out, so nobody else can mess with your account. Be sure you have saved any files you were working on, then type exit in the console window (upper left corner of the screen) or select Exit Xwindows from the menu obtained from clicking with the middle button in the root window. Never turn the computer off.
Netscape is a window-based program that displays hypertext documents from the World-Wide Web (or Web, for short). Hypertext documents can contain text, pictures, sound, movies, and (perhaps most importantly) links to other documents. The World-Wide Web (WWW) is an interconnected collection of these hypertext documents. The act of browsing the Web of documents is called "Web surfing" or "net surfing."
To run Netscape, either
The first time that you use Netscape, it will display a license agreement. Read it and click on the Accept button. Netscape will then display a window stating your account has not yet been initialized for Netscape. Click on the OK button to initialize your account; Netscape will respond by creating some special files in your account and displaying the Owlnet "home page".
In a hypertext document, phrases highlighted by color and underlining are linked to other pages; click on them to see that reference (no matter where it is in the world). Try it! To return to the previous page, simply click on Netscape's most useful button: the Back arrow near the top left of the window.
The Netscape window has a scrollbar (when necessary) on the right side. It behaves differently that the xterm's scrollbar: click with the left button above or below the highlighted part to scroll up or down, respectively.
You can directly access an arbitrary Web document by clicking the Open button at the top of the window or by just typing into the "Location" edit box near the top of the Netscape window. Fortunately, you rarely have to specify an explicit location (or URL in WWW jargon) while net surfing. Access the Comp 210 home page at http://www.owlnet.rice.edu/~comp210.
Selecting the link labeled "Labs", followed by the link "Lab 1" will give you this handout. Surf some of the other links. After lab, you should look through the Comp 210 home pages, which contain office hours, homework, a link to the course newsgroup, lecture notes for last year, and more.
If you find a document of particular interest, you can remember it by creating a bookmark for it: pull down your Bookmarks menu, and select Add Bookmark. Any time you want to revisit that page in the future, you can just select it from the Bookmark menu (where it is now listed).
To see what else the web is good for, here are a few samples:
(Once you are familiar with a Unix editor, you may want to create your own home page. To see what a web page really looks like, select Document Source under the View menu of Netscape.)
To exit Netscape, select Exit from the File menu.
One thing to watch out for: after Netscape fetches a page, it caches it, i.e., it makes a copy in your directory (inside a directory .netscape). This is usually convenient, since if you view the same file in a few minutes or tomorrow morning, Netscape doesn't need to have it re-transmitted from some other computer; it just retrieves the version it cached.
However, caching is a double-edged sword: Netscape is not smart enough to double-check with the remote site that the file hasn't changed in the mean time. If you look at a page that changes frequently, you may need to force Netscape to reload the file by clicking on the Reload button. (If you want, you may alter Netscape's caching behavior through the Options menu.)
Newsgroups are electronic bulletin boards where everybody can post and read articles on certain topics. There is a newsgroup specifically for this class, rice.owlnews.comp210. You should read the newsgroup every day or two, as helpful hints and clarifications are posted there regularly. Also, if you have a question relating to the class, post it to the newsgroup. Similarly if you have an answer for somebody else's question!
In newsgroups, the idea is that once you've read a message, you probably don't ever want to see it again (unless you do something special). So your newsreader "marks" an article as read, and next time you read news it only presents you with unmarked articles.
There are many different new-reading programs you can choose from. Two leading contenders are Netscape and Pine, each of which makes reading news analagous to their way of reading mail.
From the comp210 web page, follow the link "The Newsgroup". This opens a separate Netscape window, with three panes: the list of newsgroups (upper left), the list of articles in current newsgroup (upper right), and the current article itself (lower).
Click on an article's heading to read it, or use the Next button to go to the next unread article. You can toggle the already-read status of an individual article by clicking on the green dot next to the subject.
You can mark all the articles in the newsgroup as read by clicking on the Group button that has a picture with a bunch of checkmarks. More commonly, you will want to mark all the articles in a "thread" of conversation as read by clicking on the Thread button.
An unmarked (unread) article is shown in bold face, and has a diamond between the Sender and Subject, while a marked (read) article is in normal-font, with a dot instead of a diamond. As you read articles, you see them change from unmarked to marked.
How to do something special, to be able to read articles again later: you must change an article from marked back to unmarked.
Articles also expire after a while. For instance, you don't see articles posted three years ago, simply because the news server (the local Rice computer that gets/posts news from other computers on the net) doesn't store articles forever. How old an article has to be before it expires varies: Rice class-newsgroups tend to stay around several semesters, while articles in alt.sandwiches.pouting expire after about a week.
In the list of all newsgroups, click on a newsgroup's name to read it. Subscribed newsgroups are shown with a check to the right of their name, and unsubscribed newsgroups just have a dot; click on that symbol to toggle that particular newsgroup's subscription status.
Note that initially, only subscribed newsgroups are shown (and the class newsgroup, since you selected that one in particular to start the newsreader). Under the Options menu, you can modify this by selecting either "Show all newsgroups" or "Show subscribed newsgroups".
Some newsgroup categories (like alt, rice, etc.) have a triangle to the left of their names. When this triangle is pointing down, the view is expanded to show all newsgroups within that category; click on the triangle to toggle whether it points down or not.
To post your own message to a newsgroup, make sure the newsgroup is selected, and click the To:News button in the upper left corner. You'll be put inside an editor to compose the message. When you are done, either click the Send button to post the message, or you select Close from the File menu.
Note that under the File menu of Netscape's News window, Close just closes the News window only, while Exit actually means exiting all Netscape windows.
As with reading news, there are several different programs for sending and receiving electronic mail, including Netscape, Pine, Elm, Mail, and MH.
The Netscape mail window can be opened by clicking on the envelope in the lower-right corner of a browser window. Using the mail window is essentially like using the news window, except that instead of there being multiple newsgroups available, you can create multiple folders to contain your mail.