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Introduction to CSCS Computers

New Users Important: For Security Purposes you MUST change your password.
Please click below for instructions on how to do this.
How to Change Your password.

Once you have a login for the CSCS computers, it will work on all the CSCS Linux machines. All these machines are in the physics.lsa.umich.edu domain, i.e., to refer to them, add ".physics.lsa.umich.edu" after the machine names below.

Important: Please do NOT ssh into cscs.umich.edu

Some of these are multiple processor machines, and some are file, web and mail servers. Thus our recommended order of use, espcially for CPU intensive jobs, is as follows:

   falcone     dual processor, fastest fastest
   sciame      dual processor, faster  fastest
   tartaruga   dual processor, faster  fastest
   lastrada    dual processor, fastest
   ghiandi     dual processor, fastest
   posare      dual processor, fastest
   alveare     dual processor, fastest
   battistini  dual processor, fastest
   prateria    dual processor, faster
   pesce       dual processor, faster
   lupo        dual processor, faster
   pulcina     dual processor, fast
   volpe       dual processor, fast
   dolce       quad processor, fast
   talia       dual processor, fast
   mercato     dual processor, not so fast
   formica     dual processor, not so fast
   ospite      single processor
   pagina      single processor
   luce        single processor
   proposta    single processor
   melassa     single processor
   miele       single processor
   foglio      single processor
   panico      windows terminal server

You can find out how many tasks are using lots of cpu by entering the command: top and looking at CPU usage of the various tasks. You can also get a sample of load on some of the machines by entering the command: qhost and the output should look something like this:


[rlr@battistini Min]$ qhost
HOSTNAME     NPROC    MHz      NUSERS   LOAD     MEMTOT   MEMUSE   SWAPTO   SWAPUS  
sciame       4        3184     0        0.00     2007     234      6095     30       
tartaruga    4        3178     0        0.00     2007     243      6095     31       
falcone      4        3391     1        2.03     3991     528      6095     0        
alveare      4        2657     1        0.00     3009     619      6095     141      
ghiandi      4        2657     0        0.00     2006     366      6095     51       
posare       4        2657     1        0.00     1502     497      6095     69       
lastrada     4        2657     4        0.00     1502     100      6095     37       
luce         2        2793     0        0.00     1000     296      6095     33       
stella       2        2793     1        0.01     1000     459      6095     151      
complesso    4        2790     0        0.00     3009     272      6095     0        
prateria     2        2193     0        0.00     2006     628      6095     36       
pesce        2        2193     3        0.00     1502     380      6095     64       
lupo         2        1694     0        0.00     1000     333      6095     28       
pulcina      2        797      0        1.00     246      228      4607     200      
volpe        2        797      0        0.00     246      87       4607     34       
foglio       1        547      0        0.00     498      207      5119     0        
miele        1        547      0        0.00     498      292      5119     30       
dolce        4        500      1        0.00     498      225      519      0        
bandizzi     2        448      0        0.00     246      195      511      39       
formica      2        398      0        0.00     277      120      4671     31       
mercato      1        398      0        0.00     498      255      6139     0        
talia        2        397      0        0.06     246      116      511      30

You use the same login on any of these machines; your home directory will be the same no matter which host machine you use. Recall that you can always get back to your home directory by entering the "change directory" command with no parameters:

cd

If you are not familiar with "cd" and other basic linux/unix commands, see our local short introduction or see the tutorials referenced on the CSCS Lab's top level documentation page.

While the computer lab is open only limited hours (e.g., approximately 11am-5 or 6pm weekdays), in general the computers are all available 24 by 7 for remote use. For example, from any other machine that supports the ssh (SecureShell, or equivalent) program, you can:

    ssh pesce.physics.lsa.umich.edu

and then login to pesce (or to any of the other CSCS Linux machines, if you want to login to one of those).

Important note on security: We highly recommend the use of a secure shell program (for example, ssh) for logging into the CSCS computers from remote sites. (In fact, as of 26 Nov 2000, telnet and ftp are blocked from accessing CSCS machines from outside the CSCS Lab.) The reason is that this stops "password sniffers" from grabbing your password from the net (since ssh sends the password in an encrypted format). All the CSCS machines have ssh so you can login from them to each other or to other machines that support ssh. For example:

   ssh lupo.physics.lsa.umich.edu

or if you are logging in from a login that is different from your CSCS login:

   ssh -l yourCSCsLogin lupo.physics.lsa.umich.edu

where yourCSCSLogin is your CSCS login name. If you regularly login remotely from a machine that does not have ssh installed, let us know and we will help you obtain it. See our security page for more information in ssh an d similar programs for Windows and MacOS machines.

SecureShell (ssh) and Remote login use.

If you are accessing the CSCS machines from a remote machine, e.g., using ssh (SecureShell) or equivalent programs, you may need to set the DISPLAY enviroment variable to point to your local machine, so that programs that use X11 GUI displays will know to put displays on that remote machine, not on the console of the machine you log into. (Programs that use the X11 protocol include netscape, mathematica, emacs, and many others.) Assume your other machine is yourmachine.umich.edu, and you are logged into the CSCS machine formica.physics.lsa.umich.edu . Then do this:

1. On a session at yourmachine.umich.edu :
     xhost +formica.physics.lsa.umich.edu
2. On the session running on the CSCS machine (formica):
   If your command shell is bash (the default), use:

       export DISPLAY=yourmachine.umich.edu:0.0

   If your command shell is tcsh, use:

       setenv DISPLAY "yourmachine.umich.edu:0.0"

Note: if you use eXceed (or perhaps other programs) to access the CSCS machines from a windows environment, you may not have to do any xhost or DISPLAY setting (assuming the eXceed is set up right). But your mileage may vary...

ssh is recommened for remote connections. It usually will forward X connections (i.e. steps 1 & 2 above are usually not needed) However, in some cases ssh will not properly set the DISPLAY variable, so you will have to set it as shown above.

Your login shell

A "shell" is, basically, the program which runs in an xterm window and takes as input the commands you type in, then deciding what you want done (e.g., to run netscape, to run the emacs editor, etc). Your "login shell" is the shell that runs by default when you login. Most CSCS accounts use the bash shell. (By default, all new accounts created since January 2000 use bash.) To find out what shell you are using, enter:

  echo $SHELL

We recommend using bash and will only support other shells on a best effort basis.

Additional Documentation

One good place for novice computer users, or people new to Linux/Unix, are UM's ITD QuickNotes and other introductions to using Unix. There are pointers to online introductions to Linux/Unix on the CSCS Lab's top level documentation page.

File Backups

******* IMPORTANT --- NOTE WELL --- File Backups *******

We are currently saving home directories to tape once a week (friday night). We also keep mirrors of home directories from the 1 day and 2 days before. For more information on how to retrieve files from these mirrors or from tape go to out File Backups Page.

Permanent Large-Volume Scratch Disk Space

We have several "scratch" disk areas that are available for users to store large amounts of information. These disks are mirrored daily to protect the data in case there is a disk failure. These scratch areas are intended for storing large files that can be re-generated from other sources. For example, the most common way to use these areas is to have drone (our simulation running utility) redirect a simulation-model's output to a directory located in the scratch areas.

For information on using the CSCS scratch disk space please check out our scratch disk page.

For more information about using the scratch areas for storing simulation output (e.g., from drone experiments) see our page on how to run drone experiments.

Mail

Mail can be read on all machines. It is sent to your account on our machines or to another account based on the contents of the file named ~/.forward located in your home directory. Even though mail can be read from all machines, we strongly recommend that mail only be sent to userid@fiore.physics.lsa.umich.edu as it is the only device configured to accept incoming mail.

Updated September 1, 2005