3.A: Which Machine do I Log on to?

4.C: Logging Out

The Departmental computer cluster is a group of Unix workstations and X stations. You use your same userid and password to log on to any of them. You may logon through the console of a workstation (probably the fastest way to run) or through one of the X stations. Once logged onto one computer, you can then log onto others using the same windowing session. At present the Departmental workstations include(only the ones YOU should use for the purposes of this class):

	mentor.cc.purdue.edu
	enad302-xxx.cc.purdue.edu	(these accounts will be given to 
					 you later in the course, if required)

Usually these machines are called by their nicknames. For example, mentor is all you need to use for an address within the PUCC labs, but mentor.cc.purdue.edu if you are not logging in from a PUCC lab or are loggin in from anywhere else on the internet.

All computers in the cluster use a common file space for users such as yourself. This means that you work with the same file regardless of the machine you are on. This is a good thing as it allows you to switch from one machine, which may have a high workload, to another which is just sitting around. If you compile or interpret your programs (as happens when you run f77, f90, cc, Maple, Mathematica, or Xmgr) you should get essentially the same environment and results regardless of the machine. If you stay within the machines of one manufacturer (and therefore architecture), you can even run the same executeable (object code) on different machines. If you try to run an executable program on the wrong architecture, you should get an error message (unless you are unlucky).

In order for each machine in the Cluster to run just right for you, it must have dotfiles which are appropriate for the operating system and windowing system on that particular machine (you will learn more about these later). In the present case, this means you need different dotfiles for the IBM's and for the DEC's.

Usually when a user gets a new account on the Cluster, a bunch of standard dotfiles are automatically placed in the user's file space ("home directory"). These dotfiles let you log on from consoles and X Stations of different manufactures and designs. Normally, these dotfiles do their job with no interference on your part, and it's best not to interfere with them.

Some users feel inclined to modify their dotfiles in order to obtain that "custom look". We suggest you avoid that urge for individuality until you really know what you are doing. If you feel you "must", then keep a backup copy of the original files. Changes that may seem harmless may prevent you logging in again! In our Departmental Cluster, you can get back the standard dotfiles by telneting onto goophy and issuing the command

> getdotfiles

• So Which Machine Do I Log On To?
• What About X Stations?
• Other Questions?

3.A: Which Machine do I Log on to?

4.C: Logging Out