The scope of M data is either process local or global.
Local variables last only for the duration of the current session; GT.M deletes them when the M process terminates.
Global variables contain data that persists beyond the process. GT.M stores global variables on disk. A Global Directory organizes global variables and describes the organization of a database. The GT.M administrator uses the Global Directory Editor (GDE) to create and manage Global Directories. A Global Directory maps global names to a database file. GT.M uses this mapping when it stores and retrieves globals from the database. Several Global Directories may refer to a single database file.
For more information about the GT.M data management system, refer to the "Global Directory Editor", "MUPIP" and "GT.M Journaling" chapters in the GT.M Administration and Operations Guide.