The GDT is a data area used by the Intel 80x86 protected mode architecture for mapping selectors to segment addresses. This provides a virtual-to-physical address space translation. The purpose of the GDT is to provide a shared address space, where each process normally allocates out of a private address space maintained by its LDT. In Windows 3.x, however, all tasks share one LDT, and the GDT isnâ€(tm)t used at all. Future versions of Windows may separate the address spaces of applications by giving each application its own LDT and using the GDT for shared memory.