This diagram shows how Oracle Database XE memory is allocated and used. In the center is a round-cornered box representing the SGA. (Round-cornered boxes indicate a memory area.) Inside that box are smaller round-cornered boxes, each representing an SGA component. Smaller boxes are included for the buffer cache, the shared pool, the redo buffer, and the large pool, and one smaller box represents "other shared memory components." Above the SGA box are three square-cornered boxes that each represent a server process. (Square-cornered boxes indicate a process.) Inside each server process is a round-corner box representing the PGA for that process. Each server process has a two-way arrow leading to a small image that represents a client. (The image is a person seated at a workstation.) Each server process also has a two-way arrow to the SGA. The diagram therefore indicates that clients communicate with server processes, each with their own PGA, and that server processes all read from and write to the shared SGA. Below the SGA is a single box that represents the Oracle background processes. There is a two-way arrow between the background processes box and the SGA, indicating that the background processes access the SGA.