I am trying to answer a basic question:

Is there a way with Linux server where an application installed on the server can be accessed by different clients, with each client executing different instance of the same application and each client independently executing a different instance ?

If the answer is yes, where is this information to be found ?

Thanks !!

- Dr.Parikh

I think that generally the answer is yes. Some applications won't run multiple instances. During startup they check to see if there is another instance running. If they find one they will exit. Otherwise you can run multiple instances of almost anything from web browsers to database servers.

Where is the information? Since this functionality is generally available there isn't one place to discuss running multiple instances of software in general. For example, where would you find information for running multiple instances of Acrobat Reader? The answer is nowhere. The software just allows multiple instances. There isn't any information about how to run multiple instances because you just start the second, third, instance.

I have to infer from your question that you are having trouble running multiple instances of a particular software application. More information about the details of your situation would be helpful.

I think that the first place to look when you have questions about a specific application is the technical support for that sofware. That may be available on the web or by telephone.

I can start multiple instances of the application on the
server (i.e.the app. allows that).

However, my question/difficulty revolves around the following
issue:
how to enable different clients (connected to the server)
to execute different instances independently of
each other(a user U1 on client machine C1 is working
with instance I1, while U2 on C2 is independently working on I2 and so on).

The application is GUI based.

How to enable this functionality in Linux server world ?

Thanks in advance !

What exactly is the application in question?

Generally, if each user has their own account and their own home directory on the server then you should be able to display X applications back to the client. This is done by setting the DISPLAY variable on the server for each user. The DISPLAY variable has the form <computer>:<screen>.<?> where <computer> is the computer to display the X application, <screen> is the major number of the X display on the <computer> to display the application, and <?> is the minor number of the X display on the <computer>.

You can use rsh, rexec, or ssh to send a command from the desktop machine to the server which will start the X application. The DISPLAY variable must be configured on the server to point to the desktop machine. You can use the ssh shell to encrypt the communication from the desktop to the server simply by invoking it rather than rsh or rexec. You can use ssh encryption from the server back to the desktop by using port forwarding of the X communications. See man ssh for details.

So in summary, since you won't tell us the name of the application we have to speak in generalities.

Each person can have their own instance of an X application on the server to display back to their desktop if they have their own user account on the server. That way they don't have to share the X software files in the user directory.

You can use rsh, rexec, or ssh on the desktop to send the command to start the application from the desktop to the server.

The server has to configure the DISPLAY variable to know where to send the display of the application.

You can use ssh on the desktop to encrypt the command to start the application.

You can use ssh on the server via port forwarding on the server to send the X data through the ssh port on the server. See man ssh for more information.