The CIM Linux FAQ

This FAQ addresses some most frequently asked questions about using the linux boxes at CIM. Feel free to send more to simra.
  1. Help! I can't log in!
  2. The machine isn't responding. What do I do?
  3. Why can't I rlogin to the linux boxes?
  4. How do I mount a zip disk?
  5. How do I burn a CD?
  6. Matlab 5 crashes at startup with a segmentation fault. How can I fix this?
  7. Where can I find local disk space?
  8. How do I install package foo?
  9. Where can I get more info?
  1. Help! I can't log in!

    Many people have old versions of the cim login scripts which were written long before CIM had any linux PC's. The easiest solution to your problem is to copy the following files from ~joe:

    Also, be sure that both files are executable: 
    chmod +x ~/.xinitrc ~/.xsession;

    If your X init files are highly customized, you may wish to debug them yourself. The first clues to what is going wrong lie in your ~/.xsession.out and ~/.xsession-errors files, which will contain any error output. You can make the diagnostics more verbose by adding a '-x' flag to the opening line of your .xinitrc and .xsession files.

    You should always be able to log into the machine using the 'failsafe' selection in the session menu, or in the worst case, by typing Control-Alt-F1 to reach the console. You can return to the graphical login screen via Control-Alt-F7.

    Be aware that references to /local/X11 and /usr/X11/* in your $PATH, $path and $LD_LIBRARY_PATH are undesirable and should be removed from the linux settings in your init scripts. The only relevant path for X programs on linux boxes is /usr/X11R6/*.

  2. The machine isn't responding. What do I do?

    Do not reboot. Inform the systems staff- jan,mouse,simra or soucy immediately so we can see what the problem is. Rebooting can interrupt people's long term processing and damage the file systems.

  3. Why can't I rlogin to the linux boxes?

    For security reasons, rlogin, rsh and telnet are disabled on the new machines. The preferred method for remote access is to use 'ssh'. For example, 'ssh tafl'. If you want to set up your account so that no password is required within cim, consult the ssh man pages ('man ssh').

  4. How do I mount a zip disk?

    If you have a Windows-compatible formatted zip disk, you should be able to mount it using 

    mount /mnt/mszip
    which will mount it in the corresponding directory. If you know how to repartition and format your zip disk, and want to mount an ext2 filesystem on partition 1, use 
    mount /mnt/zip

  5. How do I burn a CD?

    CD Writing facilities are currently available on Tesserae and Halma in room 435. Here are the steps for burning a cd:

    1. Login to Tesserae or Halma.
    2. Assemble the files you want to burn under a single directory. I'll call it foo/. If you're looking for disk space, there is 3GB of free space in /tmp. Be aware that whatever you put there will disappear in 10 days. In any case, please be courteous and delete your images when you're done burning.
    3. Create the image that will be written to cd using mkisofs: 
      mkisofs -r -o /tmp/foo.iso foo/
      The -r flag instructs mkisofs to use Rock Ridge Extensions for long unix filenames, the -o filename says to send the output to filename. Note that in this case it's critical that you send the output to /tmp. The image needs to be on a local disk to prevent latencies during the write session. In this example the image will be written to /tmp/foo.iso.
    4. Insert your cd into the writer and burn the image to disk using cdrecord: 
      cdrecord -v speed=8 dev=0,1,0 -data /tmp/foo.iso
    5. Avoid any activities that are local-disk-intensive during the write process- if the write buffer empties during the session the resulting disk will be useless.
    6. When the session is done, remove the CD-R from the burner and insert it into the regular cd-rom drive (I'll look into mounting cd's from the burner later). If you're running gnome, it should be auto-mounted and you can browse the results. If not, use mount to mount the cd: 
      mount /mnt/cdrom
      The mounted cd can be browsed in /mnt/cdrom.
    For more information on CD burning, see the man pages for cdrecord and mkisofs.

  6. Matlab 5 crashes at startup with a segmentation fault. How can I fix this?

    Make sure that your $LD_LIBRARY_PATH variable contains no reference to /local/X11. You can clear the variable using 

    unsetenv LD_LIBRARY_PATH
    or set it to your own needs using 
    setenv LD_LIBRARY_PATH  colon/separated:paths:/to/dynamically:loadable:libs

  7. Where can I find local disk space?

    There is >3 Gigabytes of free disk space on /tmp on all the new machines. Be warned! This is not permanent storage! All files left in /tmp for more than 10 days are deleted. The space is there for you to use as scratch.

  8. How do I install package foo?

    If you need any special libraries or software installed, contact the systems staff and we'll make sure it's available on all the machines.

  9. Where can I get more info?

    For CIM-specific questions, contact simra. Most of the software packages installed on the machines are documented in /usr/doc. The info and man pages are also good places to find usage instructions (eg 'man ls' or 'info cvs'). For more general linux information, consult linux.org.

    Written by: Robert Sim
    Last modified August 9, 2000