In order to use a workstation that is part of the Mathematics Local-Area Network, you need to know your user name and your password. You should have received these from your instructor or from the MathLAN system manager at the time your account was created. Ordinarily, your user name is the same as your user name on the campus Windows network, but your password is not the same as your Windows password. Initially, you are given a somewhat random string of letters and digits, but you can change your MathLAN password whenever you're logged in.

Eighteen public MathLAN workstations are located in the computer lab, Science 2417; seventeen in the computer-equipped classroom, Science 2435; two in the Mathematics and Science Center, Science 2012; and one in the Modern/Waves lab, Science 1133.

Logging in

Find a MathLAN workstation that is not in use. If the screen is black, press the <Return> key; the screen will light up.

If the workstation displays the Windows network login panel, you must reboot it in order to bring up the MathLAN login panel. For instructions, see the first section, ``Rebooting from Windows into Linux,'' of the handout ``How to reboot MathLAN workstations.''

When the workstation displays the MathLAN login panel, it is ready to receive your user name and password. Move the mouse-controlled pointer onto the panel and type your user name; it will appear in the text field labelled Login. Press the <Return> key.

If you make an error while typing your user name, you can use the <Backspace> key to back up and erase one character at a time, or hold down the <Ctrl> key while pressing the <U> key to start over again, provided that you have not yet pressed <Return> to submit the line to the login program.

The login program is ``case-sensitive'' -- it makes a distinction between capital and lower-case letters. Be sure to type in both your user name and your password exactly as you received them. If your user name starts to appear on screen in capital letters, even though you're not pressing the <Shift> key, press the <Caps Lock> key (directly above the <Shift> key), then hold down the <Ctrl> key while pressing the <U> key to erase the capitals, and then type your user name in lower case.

At this point, the label on the text field changes to Password. Type in your password and press <Return>. To avoid revealing your password to onlookers, the login program replaces each character of your password with an asterisk on screen.

If the user name and password that you submitted match an entry in the MathLAN user database, the login panel vanishes, and the Sawfish window manager and GNOME desktop environment are launched. (See the handout ``Unix, GNU, Linux, Red Hat, X Windows, Sawfish, and GNOME'' for a brief explanation of what these programs do.) When the display stabilizes, you'll see a mostly blue screen with a gray panel across the bottom, containing a selection of stylish and colorful icons. At this point, you are logged in and ready to go to work.

Logging out

Here's the other half of the story: how to leave the workstation in the same state in which you found it.

Using the mouse, move the pointer onto the Log Out icon in the lower right-hand corner of the screen. It's the one that looks like a tiny computer monitor displaying a crescent moon and stars. Click the left button on the mouse.

A panel appears in the middle of the screen, asking, ``Really log out?'' Move the mouse pointer onto the button labelled Yes at the lower left of the panel and click the left mouse button. The screen flickers for a few seconds and then displays the MathLAN login panel. You are now completely logged out.

What can go wrong

User name does not appear in text field

Symptom: When you type in your user name, nothing happens on the screen. Specifically, the text field on the login panel remains blank.

Diagnosis: The user interface ignores keyboard input unless the mouse-controlled cursor lies within the window that is supposed to receive it -- in this case, the login panel. Use the mouse to move the X-shaped cursor into the center of the screen and try again.

Unrecognized user name

Symptom: After you type in your user name, the words ``Authentication failed'' appear below the Login text field.

Diagnosis: The user name you supplied was not found in MathLAN's data base. Perhaps someone hit the space bar and added a space to the Login text field before you started typing; use the Backspace key to erase everything in the field to begin again. Perhaps you mistyped your user name, or spelled it with a capital letter; in that case, simply start over. Perhaps you don't have an account on MathLAN, in which case you should have the system administrator (John Stone, Science 2418) create one for you. Or perhaps the workstation is not communicating correctly with the server machine that controls the data base of users and passwords; in this case, you should try a different workstation (and report the problem to the system administrator).

Unrecognized password

Symptom: After you type in your password, the words ``Authentication failed'' appear below the text field.

Diagnosis: Although your user name was found in MathLAN's data base, the password associated with it is different from the one you typed in. Perhaps you mistyped your password, or typed your Windows password by mistake; in that case, simply start over. Or perhaps the system administrator has goofed and the password that you were given is not the same as the one that he put in the database. In that case, have him generate a new password, impose it on your account, and tell you what it is.

Nothing on the screen

Symptom: The monitor screen is blank and does not light up when you press <Return>.

Diagnosis: Perhaps the monitor has been turned off. When it's on, the light next to the on-off button on the monitor's frame is lit (yellow or green). If this light is off, try pressing the on-off button. If this has no effect, perhaps the monitor is unplugged; find the power plug and put it into a power outlet.

If the monitor is on, but the light next to the on-off button is yellow, the monitor is not receiving any signal from the workstation's system unit. Perhaps the workstation is not turned on. When it is on, the light below the on-off button on the system unit's case is lit (usually green). If this light is off, try pressing the system unit's on-off button. If this has no effect, perhaps the system unit is unplugged; try plugging it in.

If both the monitor and the system unit are on, but the monitor light is yellow, perhaps the cable connecting the monitor to the system unit isn't securely plugged in at both ends. Locate this cable and insert it gently but firmly into the appropriate socket at each end.

Otherwise, it's probable that the either workstation or the network is broken somehow. Report the problem to the system administrator) and try a different workstation. If all of the public workstations are in similar state, you're out of luck until someone else diagnoses and solves the problem. (Look around for a sign -- if someone is working on the problem, there is probably a note on one of the blackboards or outside the system administrator's office.)

Screen locked by another user

Symptom: Instead of displaying either the MathLAN login panel or the Windows login panel, the monitor is displaying some goofy, ever-changing design. When you press the <Return> key, a panel with a red flame logo appears, displaying someone's user name and offering you an opportunity to type in a password.

Diagnosis: Someone has either started the ``screen lock'' program or abandoned the computer for more than an hour without logging out (in which case the screen is locked automatically). Ask around to see if someone has just stepped out for a couple of minutes, leaving the screen locked to prevent other people from taking over the workstation. If not, find a user consultant or the system administrator and ask to have the screen locker logged out.

Dumped back to the login screen

Symptom: Instead of launching Sawfish and GNOME, the workstation briefly displays a blue screen and then restores the MathLAN login panel.

Diagnosis: Probably your account is incorrectly configured -- one or more of the shell-configuration files (.bash_profile, .profile, or .bashrc if you are using the bash shell, .login or .cshrc if you are using the C shell) contains a disastrous error. Alternatively, the workstation may not be communicating with the server that manages the hard disk on which your home directory is stored.

Move the mouse pointer onto the word Session in the top left corner of the MathLAN login panel. Click the left mouse button. On the menu that appears, move the mouse pointer onto the word Failsafe and click the left mouse button. Then log in again. A terminal window will appear in the lower right corner of your screen. Use it to examine, diagnose, and repair your configuration files (or have a user consultant or the system administrator do so). Log out by typing the word exit at the shell prompt. The MathLAN login panel reappears; start over.

Long wait after user name

Symptom: You type in your user name, press <Return>, and nothing happens.

Diagnosis: This is most likely to occur after a workstation has been turned on but totally inactive for several days. On consulting its routing tables to find out how to communicate with the rest of the network, the workstation has found old data that it treats as potentially obsolete. It needs a minute or so to rebuild those tables with up-to-date information. Just wait -- the prompt for the password will appear after a bit. (If it does not, you should try a different workstation (and report the problem to the system administrator).

(laurel leaf logo)

created July 28, 2000
last revised July 11, 2001

John David Stone (stone@cs.grinnell.edu)