Computer Systems Frequently Asked Questions

Contact Systems Staff

To contact us for support, email your problem to adm@math.umn.edu. Your email will then be seen by our entire support staff. Do not call our offices for support unless you're unable to use email.

If your email does not work, you can call us at 612-625-4895 or just 5-4895 within the University phone system.

Please include

• the host name of the computer,

  You can find the host name by running uname -n in a terminal on Unix or Mac OS X. For example,

  johndoe@birch johndoe]$ uname -n
  birch.math.umn.edu

  A sticker on the computer, and/or monitor, should also have the hostname.

• and a brief description in the subject line of the problem.

  Subjects such as "help", "hi", or no subject are confusing and will convolute the support process.

In the body of your message, please be specific and tell us when the problem occured.

How do I change my password?

On a Linux machine in the School of Mathematics, you should get command line shell by opening a terminal.

1. Click on the menu tree starting in the top left of the desktop Applications > System Tools > Terminal.
2. You should see a window open with a command line prompt like

   [jdoe@vinh555 ~]$

   where jdoe is your username, vinh555 is the name of the computer the command line shell runs on, and the tilde character (~) is the directory the command line shell is currently in. Any characters you type should appear after the command prompts last character, $.
3. Type passwd and hit RETURN. You should be prompted for your current password once, and twice for your new password. When you type the passwords, they wont show on screen.

   [jdoe@vinh555 ~]$ passwd
   Changing password for user jdoe.
   Kerberos 5 Password: 
   Enter login(LDAP) password: 
   New UNIX password: 
   Retype new UNIX password

Remember OIT's Tips for Choosing a Good Password. In a nutshell, use more than 8 characters, a mix of upper and lower case letters, numbers and non-alphanumeric symbols. Avoid using words or phrases from any languages dictionary or technical reference. Change the password every 30 to 360 days depending on how critical the information is to you or your organization.

You can also use ssh to get a command line shell from a home computer, or another computer on the internet. See Obtaining and Using Secure Shell (SSH) for more details.

On a Windows machine press the key-combination CTRL-ALT-DEL and you should see a window pop up with a button label Change Password....

My password doesn't work, what do I do?

If the computer immediately kicks you back to the login screen, see this section.

If you have not changed your password in the last year, your password may have expired. It is also possible that your account has been locked by us. Stop by room 11 in the basement of Vincent Hall.

I forgot my password, what do I do?

If you still have your original account sheet, we can reset your password to the password listed there. Otherwise, come to Room 11 in the basement of Vincent Hall and we will reset your password.

Why does the computer immediately kick me back out to the login screen when trying to login?

You have reached the hard disk limit for your quota on our file servers. You'll need to delete some files to get below this quota before you will be able to log back in from a X-login screen. The easiest way to do this is to use a xterm from someone else's computer and use ssh to get into your account:

ssh -l 'username' localhost

Where, 'username' is your username. From there you can delete any old files to clear up the neccessary disk space. To determine how much of your quota is being used, use the following shell command:

quota -v

How do I set up a homepage and how do I access it from the internet?

To set up your homepage, run the command "homepage". This will create a directory in your home directory called "pub". Inside this directory will be a folder called "html". You should put your webpage in this directory.

homepage
cd ~/pub/html/

Your homepage can then be reached by pointing your web browser at http://www.math.umn.edu/~username/ where "username" should be replaced with your username.

I occasionally get email messages that include a selectable link to a website. How can I configure pine to open these in my favorite browser?

To do the pine configuration, go to (M)ain menu, (S)etup, (C)onfig, scroll down to Viewer Preferences and check enable-msg-view-urls (by scrolling there and hitting return). Type (E)xit, and agree to saving changes.

This will only work for links that are embedded in the message with html. You should now be able to choose a link in your mail message and hit the enter key. Pine will prompt you to select a url-viewer if you have not already. If you plan to do this from a remote location, specify /usr/bin/lynx as your browser. It's not pretty, but it'll work over slow links.

If your sure you'll only be using this feature while sitting at the actual computer, you can specify netscape or mozilla as your browser.

I haven't been able to start Mozilla under my usual profile, what can I do?

Start the web browser with the option for managing profiles.

./firefox -profilemanager

See Mozilla's profile support page for more details.

You might want to remove stale lock files from old firefox runs that didn't close properly. To find them run find ~/.mozilla -name \*lock and use the rm command to remove them.

find ~/.mozilla -name lock -or -name .parentlock -type l -exec rm {} \;

What's RSS and what software is available for reading RSS feeds?

RSS feeds are a way to pull information from websites so you don't have to check for site updates by hand. AMS' MathSciNet has RSS feeds for many journals.

The Firefox web browser has a 'live bookmark' feature that understands RSS, but you still have to remember to check the live bookmark.

The Thunderbird email client can gather RSS feeds for you automatically. By default, feeds are polled each 100 minutes and shouldn't be set below 60 minutes (lest the RSS web server become overloaded).

Thunderbird is available for Fedora Linux, Mac OS X, Windows and other unixes; various RSS software is available for different operating systems.

Create a new account folder for RSS feeds

1. Add new Account (File > New > Account...)
2. Select "RSS News & Blogs"
3. Optionally change name from "News & Blogs"

A new globe icon should appear with the label "News & BLogs"

Add an RSS feed to the account

1. Right click on the label "News & Blogs"
2. Select "Manage Subscriptions..." from the menu.
3. On the window that appears, click the "Add" button.
4. Enter the RSS feed's web address.
5. Optionally click "Show the summary instead of loading the web page".
6. Click ok.

Add additional RSS feeds, and read RSS notices like email.

Note: Thunderbird's RSS subscriptions aren't stored in on the mail server, so using Thunderbird at home, work or other locations requires setting up the RSS at each location. Even with all Thunderbird clients configured for RSS, using the UMN web mail program still won't have access to the RSS information.

If having RSS feeds delivered to an email inbox is important, look into RSS proxy programs

RSS to Email Software

rss2email
Feed Parser
Newspipe

Printer List

Are any printers safe for printing tests and grades?

Yes, vinp105-cfdl in room Vincent Hall room 105 is. This is how you would would use the "lpr" command to yprint to it:

lpr -Pvinp105-cfdl

Can I print when I am on the notebook network?

Yes, please see the following documentation.

How can I configure pine to print email messages to deparment printers?

To configure pine to do this, go to (M)ain menu, (S)etup, (P)rinter, press arrow-down key until "Personally selected print command" is selected. Then type "A". Pine will ask for the name of the printer. Just press the enter key to set the printer name to nothing. Pine will now ask you for the command. Enter somthing like "lpr -Pname" where "name" is replaced with the name of the printer you want. Now type "E" to exit the setup menu.

Why won't my KDE app (kdvi, kile, etc.) print?

1. Open whatever KDE based program (kpdf, kdvi, etc..).
2. Go to "File -> Print"
3. Click on "System Options"
4. On the left scrollbar, scroll down to CUPS Server and click on the icon
5. In the host entry field it probably says "localhost", change that to "cups.math.umn.edu". Leave the port as "631".
6. Click Ok, and it should now work.

Is wireless available in the department?

Yes, wireless is availabe. UofM Wireless should be available throughout most of the department. Choose UofM Wireless with your laptop's wireless utilities, and then open a web browser to login with your University x500id. Printing is not available when using the wireless network.

Can I attach my laptop into the department's network?

Faculty and Visitors can request wired laptop connections. Some offices may already have wired laptop connections, which are denoted by a grey cable. If you do not have a grey cable in your office and would like wired access, please contact adm@math.umn.edu.

Once a wired connection is setup, connect your laptop to the grey cable, and open a web browser to any web site. You'll be asked to log in with your School of Mathematics id.

Don't unplug your office computer's network cable. Attaching your laptop to your office computer's port will disable the port.

Are any projectors available to use in presentations?

Several classrooms have projectors built in, and portable projects can be checked out by contacting Stephanie Lawson.

How do I use MSDOS formated floppy disks?

The mtools software mimics MS-DOS's commands for accessing floppy disk (included support for the a: prefix). Some examples are below, and more complete info is available with command man mtools.

Format (erase) the disk: mformat a:

List the contents of the floppy disk: mdir a:

Copy a file to the floppy disk: mcopy myfile a:myfile

Copy a file from the floppy disk: mcopy a:myfile myfile

Delete a file on the floppy disk: mdel a:myfile

Create a directory on the floppy disk: mmd a:mydirectory

Copy a file to a directory on the floppy disk: mcopy myfile a:mydirectory/myfile

List the contents of a directory on the floppy disk: mdir a:mydirectory

Remove a directory on the floppy disk: mdeltree a:mydirectory

To read the manual page for all of the mtools: man mtools

My mouse isn't working correctly, what do I do?

If you can't access menus like you normally do, make sure your Num Lock key is off (the numlock light should be off).

If you can't find your mouse, or it's stuck in an upper corner, try spinning the mouse wheel (assuming your mouse has a wheel). This is caused by a bug in our X-server software. Software upgrades should fix this problem soon.

If your mouse behaves erractically or doesn't work at all, it is possible that we have misconfigured your mouse or your mouse might be failing. Send email to adm@math.umn.edu to report the problem.

When my office machine is reinstalled, will the crontab be preserved, or will it be overwritten?

When a machine is reinstalled, it doesn't have cronjobs for users accounts in /var/spool/crontab. The remedy is to set your login shell to reinstall a set of cronjobs whenever you start a shell.

1. Make ~/.crontab contains the cronjobs like they appear with crontab -l.
2. Add "crontab -f ~/.crontab" to your ".bash_profile" file. The .bash_profile runs when your account starts a new bash login shell (aka you open a terminal window, or start an ssh connection).

How can I burn a CDROM?

You'll need a blank CD-R and access to a CD burner. The computers in 314 are all equipped with burners, and the program k3b should do the trick for custom CDs.

If you already have an iso image, you can open a file manager window, right-click on the iso image file, and select "Burn to Disc" from the menu.

CDs can also be created with the command line applications mkisofs, and cdrecord or growisofs.

Can I get text message reminders from UMCal?

Yes, start ocal desktop client for UMCal.  If you haven't already, configure the UMCal desktop client.  Go to the menu Tools > Options > Agenda....  Go to the Notification tab, and set the Alternate e-mail address field to the text message email address of your cell phone.  Any events with reminder alerts should send text messages to your cell phone.

Click for a larger image

UMCal is a calender service offered at the University of Minnesota.

Running Matlab on Your Home Machine

UMN students can buy a student copy of Mathwork's Matlab software for about $90.

If you're just starting with matlab scripting, you might try installing Octave. Octave is similar to Matlab and is a free download, but doesn't have the high end toolkits.

Running Matlab on a Remote Machine From Home

To run matlab on a remote machine, you'll need an ssh client to run matlab from the command line, and XServer software to run matlab GUI desktop. Mac OS X comes with an Xserver application and ssh and so does Linux. Windows users will need an ssh client like PuTTY or the OpenSSH included in Cygwin. Cygwin also includes an XServer, but PuTTY users need to install X-Win32 to do X-forwarding. PuTTY and Cygwin are free, X-Win32 is about $115 for an educational license.

Once you have ssh and an X Server installed, run "ssh -Y birch.math.umn.edu" to log in to a host named birch. Older versions of ssh use the "-X" option instead of "-Y".

After logging into birch, start matlab by running "matlab &" for the desktop version, or "matlab -nojvm" for the command line version.

If a faculty member wants to sponsor your math account we can create one for you. Matlab is in the School of Mathematics, ITLabs computers if you have an active account there.

www.math.umn.edu/systems_guide/faq/ Last Modified July 30, 2008 Contact the School of Mathematics The University of Minnesota is an equal opportunity educator and employer. © 2009, The Regents of the University of Minnesota

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