Welcome to the Physics Workstation Cluster!

You may use your login name and password on any of these machines:

Use of Cluster Accounts

Cluster accounts have all user files stored in a central location. When you log into your cluster account from any of the 9 machines, you will start in the same place: a directory called

/users?/username 

where ? is either A, B, C, and username is the name you have on the computer. This directory is the same for all 9 machines. If you log into mango and delete your file thesis.tex then it is gone, you will not find another copy on a different machine.

Dealing with Centralized Files

Having all your files in a central location is wonderfully convenient but does bring up a few complications. First, binary files compiled on one machine may not work on another. Specifically, programs compiled on an IBM will not run on a DEC. They will have to be recompiled. In the end this just means you may have to do a little recompiling, or keep separate directories for executables of different persuasions. Another difficulty is with dotfiles (setup files whose name begins with a period and which do not appear with a regular ls command). Dotfiles determine the configuration of your enviroment and need to do different things depending on what machine you are logging into and where you are doing it from. As a result a group of dotfiles have been created which identify the host and terminal you are logging in on and then do the appropriate setup (if all goes well). Normally, these should work and you can ignore them. However, if you feel inclined to modify them in order to customize your enviroment be sure you understand how they work do so on your own risk. If you mess with your dotfiles and get lost try to telnet into goophy or daphy and issue the command getdotfiles which will copy the default dotfiles to your home directory. If you can't even do that find a system administrator to help but don't expect to her/him to be thrilled about it.

About Passwords

Cluster accounts have passwords managed by NIS (also know as yellow pages--although that name violates a British Telecom trademark). This means that one password works for all nine machines. To change that password use the passwd command from any of the 9 machines. (Note that the standard dotfiles alias the regular Unix passwd command to yppasswd, do NOT change that!). Once you've changed your password the new password will work on all the machines. Because of this setup the standard Unix commands chsh (to change your default shell) and chfn (to change the name, phone number, office type information associated with your account) will not work. We suggest editing the provided .plan file for your personal information and asking a system administrator to change your shell.

About Email

We strongly encourage you to get a ucs account for your email. They have the latest hardware, software and the necessary manpower to ensure that no mail gets lost. If for some reason you really, really, really want to use a Physics machine here are some things you should know. Your email address is username@physics.orst.edu. You can send mail from any machine but the only machine where you can receive/read mail is a virtual machine called physics.orst.edu. The physical machine which answers to this name can be any of the real machines (at the moment it's graphy). You should get used to the idea that in order to read your mail you log into physics.orst.edu. Whatever happens there will always (whatever that means in Physics) a machine which answers to this name and has full mail support.

So Which Machine Do I Log Onto?

This is a rather tough question. You probably want to use the fastest machine. In theory this is daphy but if two or more people are using it then it will be slower than one of the tropical fruits with only one user. To find out who else is using "your" machine use the who command. To go to a different machine without logging out, click with your right mouse button into the background of the screen and select a different machine.

X-Station Issues

A few simple facts. As of now our five old xstations (the IBM x120's with the small screens) only allow you to log into one of the IBMs. The new xstations (ncd1 - ncd12) have two host selection windows. Double clicking on a host in the LARGER window will set up a dumb telnet session. This is usually fine (and fast!) if all you want to do is check your mail on ucs or physics or if you want to acces a machine outside the department. The SMALLER window is often hidden behind the larger one. It allows you to start a xsession with access to maple, netscape and and and.

Can I have a Web Page?

To create your own home page create a directory public_html in your home directory, steal and modify someone's home page (Netscape's save command) put it in your public_html directory and name it index.html. Direct your browser to http://www.physics.orst.edu/~username and hurray you have a home page. To get a link from your the Physics Department home page http://www.physics.orst.edu/ to your page, send email to support or find a system administrator.

What about Research Jobs?

The Cluster was bought for instructional purposes and not for research. If you run a research job on any of the cluster machines which requires more than a couple of minutes computing time, run it in the background and at night. We will kill research jobs on the cluster according to the following rules. DEC: Research jobs on these machines affect the overall performance of the whole system. Jobs running during the day 8am - 10pm will be killed whenever none-research demand is significant. IBM: Research jobs running on these machines during the day 8am - 10pm will be killed whenever a class is taught in Weniger 412.

Other Questions?

Your best resource is probably the person sitting next to you. If that doesn't work, look up the manuals in the computer room. Dr. Landau's book is available, and there are also one book on Unix and a relatively thin paper which gives a quick start. If you want to look up quickly the various options for a command, the man (short for "manual") pages will be the quickest way. Just type "man command". If none of these tell you what you want to know, try to find the graduate-student system manager. There are also informed/computer-oriented faculty members, in particular, Landau and Jansen. There are a number of grad students who may know the answer to your question better than any of the people above. Fortunately, they are also the ones who are most often in the computer room. Just ask. Usually, what you want to know has been done by someone else before.

If there are problems with the systems, send email to "support", and your report will be taken care of.

Security

Security of the machines and of the data on them is a major issue. Here are some policies (self-enforced) that will help prevent break-ins and destruction of data by a third party.

logging out:

NEVER leave your computer without logging out or, if you leave for only a couple of minutes (<10), locking your terminal. If you run a telnet session (text only) just type logout, press enter and if you didin't do anything fancy you are done. If you run a xsession on goophy or daphy you have a menu bar at the top. To log out, click on "Session" and select "End Session" to log out and "Pause" to lock your screen. On any other machine click with your left mouse button in the background and select the appropriate entries. If you find a computer where someone forgot to log out, don't assume he/she will be right back, log that person out.

Passwords:

Your password is your own. No one else must know it. Do NOT share your account with other people by giving your password out to them. Anyone found doing this will have their access to the machines revoked. Please don't do it.

Keep your password secure. Don't keep your password in a file in your account, even with proper permissions set. Don't write it down. Remember it.

Make a good password. Your password can be up to 8 characters long, including numbers and punctuation. Make sure the password is a full 8 characters long. Don't use dictionary words in any language. Don't use sensitive information like your social security number. Don't use proper names. Most of all, don't use your username. Mix letters, numbers and punctuation in your password. Mix lower and upper case letters, too. A good way of generating a secure password is to think of a phrase, and then take the initial letters of the words in the phrase, randomly capitalizing and adding numbers or puncutation in. Keep a set of 3 or 4 of these in mind, so you can change your password regularly. Once or twice a term is a good interval for changing. Here's an example of generating a password:

We will occasionally try to crack passwords. If anyone's password is found to be crackable, it will be changed. That person should then see one of the systems administrators (Hans Kowallik, Keith Goldman) to get a new password.

File permissions

Make sure your files and directories have permissions that are reasonable. To see what permissions are set, do "ls -l" for a long listing with more information. The first column of information lists the type of file and the permissions on it. For example

The fields are, in order, permissions, number of links, owner, group, size (in bytes), modification date and time, and name. A slash after the name denotes a directory. A "*" after the name denotes and executable.

There are 10 characters in the first column. The first indicates the type of file: a "-" means that it is just a plain file, and a "d" means that it is a directory. Then comes 3 sets of 3 characters. The first set is permissions for the owner (user), the second set is permissions for the group, and the third set is permissions for others. The group is what is shown in the group field in the long listing, "users" in the example above. In the permissions fields, "r" means "read", "w" means "write", and "x" means "execute". For a directory, "execute" means being able to "cd" into that directory. Read the man page for "chmod" (do "man chmod") for information on how to change the permissions. The default for files is "-rw-r--r--" and the default for directories is "drwxr-xr-x".