SAP Business Objects Enterprise XI 3.1 is a multitier, server-based program consisting of a series of logical servers. Note that the logical servers are not actually physical servers. The logical servers run as services such as Windows Services and consequently can be installed on a single machine or distributed across multiple machines. The logical servers communicate with each through the Common Object Request Broker Architecture (CORBA). As the number of users and user requests being made increase place increased burden on the SAP Business Objects system more SAP Business Objects services can be installed and configured. This is known as scaling the Business Intelligence platform. The additional services can be installed on existing machines, however, it may be also necessary to increase the available CPU or add new machines to the cluster. SAP Business Objects Enterprise can be installed on several platforms including Windows, Unix and Linux. Check the SAP Business Objects Supported Platform Guide for more information.