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1   Quick Installation

Several demonstration applications are included with Ensemble. These can give a sense of the kinds of facilities provided by group communication to those who have not used a group communication toolkit before. The demos can also serve as starting points for building new applications. These applications are briefly described here along with how to execute them and the various command-line options and environment variables they use.

1.1   Compiling

Please see the file ensemble/INSTALL for instructions on installing Ensemble if you have not done so already.

1.2   Environment Variables

Detailed information is given in Section ?? for initializing environment variables. Here we give the bare minimum you need in order to get started. We assume that you will (at least initially) be using the gossip server for processes to locate each other. ENS_GOSSIP_PORT must be set to a port number that is not used by other applications. Normally, user applications cannot use port numbers below 1000. ENS_GOSSIP_HOSTS must be set to a list of colon-separated host names where the gossip server may be found. If you wish to use port 7500 for the gossip server on hosts ``ely'' and ``natasha,'' you would set these environment variables as follows (in Unix csh):
% setenv ENS_GOSSIP_PORT 7500
% setenv ENS_GOSSIP_HOSTS ely:natasha
Throughout this tutorial, we assume you are using the Unix csh or tcsh shell. To set an environment variable in the bash shell, you would do the following:
% export ENS_GOSSIP_PORT=7500
% export ENS_GOSSIP_HOSTS=ely:natasha
Remember that these must be set for all Ensemble programs you run. You may wish to add the configuration to your .cshrc or equivalent.

1.3   Executing Applications

Applications by default require a gossip server process to be running in order to contact each other. Before executing an application, a gossip server must be started one of the hosts listed in ENS_GOSSIP_HOSTS:
% gossip
 ...
On the same or other hosts execute several instances of an application, such as demo/mtalk:
% mtalk
 ...

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