This page contains some extra exercises for you to do as part of Lab #0 for CS100: Principles of Computer Science. It also contains a written exercise that you should include as part of your lab report for Lab #0.
Since you are reading this, you've already started using Netscape to browse the World Wide Web, and you already know the basic idea: Click on any underlined, colored "link" to follow it to a new page of information.
Your first exercise is just to continue browsing, looking for interesting, entertaining, educational, and useful pages. You can start from the HWS "Links to All Over" page. (You'll probably want to spend some time in Yahoo, and you should definitely try the Webcrawler.)
Exercise #5 for Lab #0: Briefly describe one or two of the most interesting Web pages you found. Don't use pages that are already directly linked to the "Links to All Over" page. Give the URL of each page. (The URL is the address of the page; when you are viewing a page you'll find its URL in the box labeled "Location" at the top of the Netscape window.) Turn this exercise in along with the other written exercises from Lab #0. After I collect the lab reports, I will post a list of your pages on the "Most Complex Machine Home Page."
This part of the lab is optional, but unless you already know how to use email, I hope you will do it. Email is an effective way to communicate with me.
The (optional) exercise is to send me an email message. Thse rest of this page contains information about using email.
Note that even if you already use email, you might want to read the section on advanced email at the end of this page.
Email through Netscape: You should be aware that some links in Netscape are actually email links. Clicking on an email link is supposed to open a window where you can type an email message. Unfortunately, this will not work very well for you, since it will only work correctly if Netscape is set up with the correct information for sending and receiveing your email. Since you are using Netscape in a lab setting, it won't be properly set up. (The setup is done using the Preferences... command in Netscape's Options menu, under the "Mail and News" heading.) Go ahead and try it if you want, but my advice would be to avoid using email through Netscape.
Email in the Gulick Lab: The computers in the Gulick microcomputing lab have a menu entry on their main screen for using email. There are monitors there to help you if you have questions.
Email through the VAX: The VAX is the Colleges' main computer. You have a username and password for an account on the VAX. (If you forget your password, you will have to see Barry Jones in Williams Hall.) You can send and receive email through this account by "logging on" to the VAX. (This is the same email account that you can access through the Gulick Lab.) You can log on to the VAX through terminals in Williams Hall, by modem from your dorm room, or by using the NCSA Telnet program on a Macintosh computer in Rosenberg 008 or Lansing 312. No matter how you connect, once you are connected the procedure will be the same.
The first step is to connect to the VAX. How you do this depends on where you are. You will know you are properly connected when the computer asks you to enter your username by typing "USERNAME:" on the screen.
If you are at a terminal in Williams Hall, you just have to make sure the terminal is turned on and then press the return key. If you are using a modem to phone in, set it to dial the number 3332, or 781-3332 from off campus. (The default settings on your modem should be OK.)
From a Macintosh in Rosenberg or Lansing, you will use the program NCSA Telnet to connect to the VAX. It is possible to start up this program and connect to the VAX through Netscape by clicking on a link like this one:
Telnet to the HWS VAX.
You will find a similar link on the Most Complex Machine Home Page. You can also make the connection by hand by following these steps:
However you make the connection, a window should open showing you the prompt "USERNAME:". Once you see this, you are ready to log in.
You log on to the VAX by entering your assigned username and password. When the computer asks you for "USERNAME:", type in your username and press return. The computer will ask for your "PASSWORD:". Type it in and press return. (For security, the password will not appear on the screen as you type it.)
If you don't enter your username and password correctly, you will get an error message. Just press return to get another USERNAME prompt, and try again.
Once you have logged on, the computer will print a bunch of introductory stuff. Eventually, it will type a $ and stop. The $ is the "command prompt" on the VAX. It means that the computer is waiting for you to type in a command. There are many different commands that the VAX understands, but I am only interested in one here, the MAIL command. (If you are interested in learning more about the VAX, come and talk to me about it.)
To access the email system on the VAX, type "mail" at the $ prompt (without the quotes). The computer will respond with the mail prompt "MAIL>". When you see this prompt, you can type in any email command.
If you have mail waiting for you to read, then as soon as you enter the email system you will see a message telling you how many messages there are waiting for you. All you have to do to read these messages is to keep pressing return at the MAIL> prompt.
To send a message, enter "send" (without the quotes) at the MAIL> and press return. The computer will prompt you with "To:". Type in the email address of the person you want to write to. For students and faculty, the email address is just the person's username. For example, to send me mail, you would enter "eck" (without the quotes) at the "To:" prompt. Not everyone's user name is the same as their last name, though. To send mail to administrators, who have accounts on another computer, you have to put "hws2::" before the user name. For example, to send email to President Hersh, you have to respond "hws2::hersh" (with no quotes and no spaces) to the "To:" prompt.
To send email to someone off campus, you need to know their full Internet email address. For example, my Internet email address is eck@hws.edu. (Your own Internet email address is of the form "username@hws.edu". Anyone on the Internet who knows this address can send email to you.) The syntax for sending email off campus is a bit silly: At the "To:" prompt, you have to enter something of the form:
in%"eck@hws.edu"
including the quotes and with no spaces. Of course, you substitute whatever email address that you want for eck@hws.edu.
After you have responded to the "To:" command, the computer will prompt you for a "Subject:". You can enter a single-line subject description for the message you want to send.
Finally, you get to type in the message. Just type it in, pressing return at the end of each line. Once you press return, there is no way to go back and make changes. Be sure to press return at the end of each line! (If you type in more than 255 characters without pressing return, you'll get an obscure error message and the computer will throw away all the characters you just typed!)
When you finish typing the message, press Control-Z. (This means, hold down the key labeled "Control" or "CTRL" and hit the Z key.) If you want to abort the message without sending it, press Control-C instead. (Before you type the message, the computer types a little note reminding you about Control-Z and Control-C.)
Note: If you have just finished reading an incoming message, or are in the middle of reading it, you can reply to that message by entering the command "reply" at the MAIL> prompt. The computer will fill in the "To:" part for you and will fill in the "Subject:" part if the note you were reading had a Subject.
This is enough information to get you started using email, but once you've started using it, you should definitely read the section on advanced email below.
When are finished with mail, enter "exit" at the MAIL> prompt to exit from the mail system and get back to the $ prompt. Then, enter "logout" at the $ to break your connection with the VAX.
If you are using a modem or NCSA Telnet to connect, exiting and logging out are not so important, since the connection will be broken automatically when you hang up the phone or quit the program. If you happen to be using mail at a terminal in Williams Hall, however, it is very important that you log out. Otherwise, even if you turn off the terminal, the connection will still be there for a while and if someone else comes along and uses the terminal, they will be able to use (and abuse) your computer account.
set personal "Your Name"
Include the quotes. (Substitute your own name -- or whatever "handle" you want to use -- for Your Name.)
You only have to do this once, and the mail system will remember your name permanently and include it will all your messages. (It will turn up in the first line, labled "From:", at the top of the message.)
dir
at the MAIL> prompt. This works two ways, depending on whether you have new messages or not. If you have new messages waiting for you when you enter the mail system, then the "dir" command will list only the new messages. If there are no new messages, then "dir" will list all the old messages that you have already read, unless you have explicitely deleted them. (If you do have new mail but would like to see a list of your old messages, say "dir mail" instead of just "dir.)
What can you do with a list of messages? Well, you can pick one out and read it. The list of messages will be numbered. To read message number 5, say, you would say
read 5
at the MAIL> prompt.
All the messages you receive just keep building up unless you explicitely delete them. When you are reading a message, or when you have just finished reading it, you can delete it by typing the command
del
at the MAIL> prompt. Also if you are looking at a directory listing of your messages, you can delete messages by number (for example: "del 5"), or you can delete a range of message numbers (for example: "del 5-10" will delete messages number 5 through 10).
When you are reading a message, or when you have just finished reading it, you can forward a copy of that message to another email address simply by using the
forward
command at the MAIL> prompt. You will be asked to enter the address to which you want to forward the message and for a subject line for the forwarded message.
It's easy to send the same message to several different addresses. When the computer types the "To:" prompt to ask you for the recipient of the message, just enter a list of addresses, separated by commas (for example: eck,hws2::hersh,in%"weyman@neu.edu").
There is an old tradition of "CC-ing" a message to people other than its addressees. ("CC" comes from "carbon copy.") If you would like to CC your message to one or more addresses, you just have to add "/cc" to the "send" command (without the quotes; that is: send/cc). Then, after you respond to the computer's "To:" prompt, the computer will prompty you with "CC:", and you can enter one or more addresses to receive a copy of the message.
You could, for example, CC the message to yourself, so you could have a copy to keep. This is so common that the mail system makes it easy. To send a copy of the message to yourself, just add "/self" to the "send" command (that is: send/self).
You have space in your computer account on the VAX for storing files. (And there are, by the way, ways of getting files back and forth between your computer and the VAX.) You might have a file that you want to send to someone via email. This is easy. Just put the name of the file after the "send" command. For example:
send myfile.txt
where "myfile.txt" is the name of the file. You need a space after the word "send".
When you use email in Gulick, you get to type your message in a "full-screen editor" where you can use the arrow keys to move around in the message. This lets you go back and make changes in a line after you have pressed return.
You can do the same thing in the VAX email system if you just add "/edit" to the "send" command (that is: send/edit). You can also use "/edit" with "reply" (that is: reply/edit) and "forward" (that is: forward/edit). But before trying this, make sure you know how to get out of the editor!
When you are editing your message, you can use the arrow and delete keys as you would expect. There are also a lot of other neat editing keys that you can use, if you want to learn about them. Once you have finished entering your message, type Control-Z (that is, hold down the key labled "Control" or "Ctrl" and hit the Z key). You will get a blinking cursor next to a * at the bottom of the screen. Type "exit" (without the quotes) and press return. This will send your message.
If you decide to abort the message you are typing, you must still press Control-Z. When you get the *, type "quit" and press return. The message you were typing will not be sent.
There is one other editing command that you should probably learn about before using the editor: If the screen becomes corrupted -- for example, if you get a notification of a new incoming mail message -- press Control-R (for "Refresh") to redraw the screen.
(Note: With "forward/edit", you get to edit the text of the note you are forwarding. With "reply/edit", you get get a blank screen to type your reply. The command "reply/extract" lets you edit a copy of the note you are replying to, which lets you include a copy of the original note in your reply.)