In computer science , inter-process communication or interprocess communication ( IPC ) refers specifically to the mechanisms an operating system provides to allow the processes to manage shared data. Typically, applications can use IPC, categorized as clients and servers , where the client requests data and the server responds to client requests.  Many applications are both clients and servers, as commonly seen in distributed computing . Methods for doing IPC are divided into categories which vary based on software requirements , such as performance and modularity requirements, and system circumstances, such as network bandwidth and latency . 
call one’s shots To verbalize what one intends to do or in what manner one intends to act; to inform others of one’s plans. This phrase probably derives from various billiards games in which a player must call out the shot he plans to make before attempting it. The similar expression call the shots shifts the emphasis from one’s personal domain to a larger frame of reference in which an individual attempts to direct or control events, to be in charge, or to be in the driver’s seat. Call the shots may derive from the director’s role in film making.