What are the differences between SAP memory and ABAP memory?

ABAP Memory is a memory area in the internal session (roll area) of an ABAP program. Data within this area is retained within a sequence of program calls, allowing you to pass data between programs that call one another. It is also possible to pass data between sessions using SAP Memory.

SAP Memory is a memory area to which all sessions within a SAPgui have access. You can use SAP memory either to pass data from one program to another within a session (as with ABAP memory) or to pass data from one session to another.