ABAP FAQ's,

->What are the functions of dispatcher ?
Ans)Equal distribution of transaction load to the work processes
Management of buffer areas in main memory
Integration of the presentation levels
Organization of communication activities.

->What is a work process ?
Ans) A work process is where individual dialog steps are actually processed and the work is done. Each work process
handles one type of request.

->Name various work processes of R/3 system ?
Ans) Dialog or Online ( processes only one request at a time )
Background ( started at a specified time )
Update ( primary or secondary )
Enque( lock mechanism )
Spool ( generated online or during back ground processing
For printing )

->Explain about the two services that are used to deal with communication .
Ans) Message service : used by the application servers to exchange short internal messages , all system communications.
Gateway service : enables communication between R/3
and external applications , using CPI-C protocol.

->Which work process triggers database changes ?
Ans) Update work process