ABAP Runtime Environment (BC-ABA)

Part of the application layer of an AS ABAP. The application layer can be spread over multiple application servers that are usually instanced on different computers whose operating systems must not be identical. However, it is also possible for multiple application servers of one or more AS ABAPs to run on one computer. Application servers communicate with the presentation layer, the database layer, and with each other using the Message Server. The most important components of an application server are its work processes, the number and type of which are specified when an AS ABAP is started. An ABAP program is executed by a suitable work process of an application server. The memory areas of an application server that can be accessed in ABAP programs are the shared memory, the SAP memory, the ABAP memory, and the roll area in the internal session.