The Oracle E-Business Suite (EBS) is a complex Enterprise Resource Planning (ERP) program that consists of many components. The primary components that comprise the E-Business Suite are the Client, Forms Server, Web Server, Concurrent Processor, and Oracle Database. For a more detailed description (with screenshots), download the document at http://blog2.enkitec.com/wp-content/uploads/2010/05/Creating-a-concurrent-processing-expressway-in-Oracle-EBS-11i1.pdf.
User interactions with Oracle Applications data are conducted via HTML-based Applications or the more traditional Forms-based Applications. However, there are also reporting programs and data updating programs that need to run either periodically, or on an ad hoc basis. These programs may contain a very large number of data-intensive computations, and are run using the concurrent processing architecture. To ensure that resource-intensive concurrent processing operations do not interfere with interactive operations, they are run on a specialized server, the Concurrent Processing server. Processes that run on the concurrent processing server are called concurrent requests. When you submit such a request a row is inserted into a database table specifying the program to be run. A concurrent manager then reads the applicable requests in the table, and starts the associated concurrent program. The Internal Concurrent Manager controls the other concurrent managers, and determines when a request should be processed and which concurrent manager should carry it out.