Creative Connections
While many people connect to Bama only using Netscape or a mail program, there are a variety of ways to connect to the machine. Also, most users who connect to Bama simply stay on Bama but there are ways to go off of Bama and connect to other machines where you have a valid account.
Getting to Bama
The choice of connection depends on the type of application to be run. The simplest connection is through telnet from a PC or another workstation. The name "telnet" comes from an old connection protocol (of the same name) that set up a standard for communicating between machines. This started out on Unix machines (and is available on Bama). Even though "telnet" is included with Windows95 we recommend that you get a more fully functional telnet such as TeraTerm. Windows 3.1 has no telnet at all, so in that case you must get TeraTerm. This is available free over the Web at
When you use telnet, you will tell it to connect to Bama, then you will be asked for your login name and password, at which point you will be directly connected to Bama. Once you are logged in, Bama expects you to issue Unix commands. Some of these are covered in previous TIPSHEETS, however, you can use any Unix book to help you at this point. You are not restricted to running one telnet. You can have as many telnets, and thus, as many logins, as you need. They will all run independently of one another.
Telnet programs are designed to imitate some of the old stand-alone terminals that were used to connect to computers (but which have all but disappeared) such as the DEC vt100. Some telnets also imitate graphics terminals that were common enough to become standards. For instance, TeraTerm can imitate a Tektronix 4010. The telnet program is also designed to tell Bama what type of terminal it is so programs on Bama which need to know the terminal-type can operate correctly. Examples of such programs include "vi", "pine", "lynx", and "pico". These programs let you use the "arrow" keys to move the cursor around the screen. This communication happens automatically and usually doesn't concern the user but occassionally a program might want more functions in the telnet program than it is configured for. This happens in the telnet program supplied with Windows95. It cannot adequately handle the program "vi" and we don't recommend that you use that combination.
Getting off Bama
If you have an account on another machine that accepts telnet connections, you can get to it from Bama. Simply type
telnet machine.ip.name
where "machine.ip.name" is the machine's ip name or numerical address.
Bama also has rlogin, rsh, and rexec. See the man pages for more information on using these commands.
The X Connection
"Windows" is not a term that applies only to Macintoshes and, certainly not, to Microsoft. Long before Apple and Microsoft started using windows, a project was started at MIT which resulted in "X-Windows". Sending and receiving output in these windows was machine-independent so the idea quickly spread among different machines and has become a standard. These look like the Windows that users are now comfortable with on PCs and MACs. There can be multiple, open displays ("programs") running and they can be put to the side as icons and accessed again later. The windows can be moved around the screen, and can be resized, too.
Bama supports X-Windows. To use them you have to connect to Bama with a machine that also uses X-Windows. These are common on Unix workstations but are not a native part of Apple or Microsoft systems. They must be added on as new software.
Under X-Windows you would tell Bama that it is to display on some remote machine which is running X-Windows. There is an environment variable that controls this called "DISPLAY". In the ksh it is set like this:
DISPLAY=my-machine-ip-name:0.0
export DISPLAY
where "my-machine-ip-name" is the name of the remote machine. From then on, any newly started program that expects to use X-Windows will display on the remote machine. You are still running it on Bama, it just is putting its output somewhere else. There might be some setup required for negotiating permission for Bama to display on the machine running X-Windows, but the details of this depend on the X-Windows program being used.
What are some examples of X-Windows programs on Bama? Well, there is "netscape", SAS also runs in X-Windows mode, there is an image editing program called "xv", and there are a number of other programs that will display to windows.
On PCs and Macs the idea that that one could change the way the windows look isn't an issue, but it is under X-Windows. The program that controls the windows is called a "window manager" and there are many different ones available. Right now on Bama there are three; OpenWindows (the Sun standard), CDE (a new standard which Sun helped develop), and twm (the "tab window manager", which is about as old as X-Windows, themselves). Others may be added in the future.
There are many vendors of X-Windows software for PCs and Macs. On campus we are experimenting with a system from Starnet called Xwin32. You can call the HelpDesk for more information about this one. There is also a free X-Windows system called MI/X, which has versions for PCs and Macs, but it has limited functionality.
X-Windows can generate a lot of traffic on a network so we don't recommend you use them when simply a "telnet" session will do. They also work terribly slow over a modem connection. However, there are times when the functionality of Bama is greatly increased by running programs through the windows.
© 1998, The University of Alabama. The information included here is for the University of Alabama central computing facility as it was configured on the document date. It may or may not apply to other Unix systems.