EMM386EXE
EMM386.EXE is a DOS device driver that provides Expanded Memory (EMS) support on x86 PCs. It functions as a memory manager in tandem with HIMEM.SYS, allowing programs that require EMS to run on systems with limited conventional memory. EMM386 creates a virtual EMS environment by paging portions of extended memory into an EMS address space, enabling software to access EMS memory without occupying conventional memory.
In addition to EMS support, EMM386 can help optimize conventional memory usage by creating upper memory blocks
Usage of EMM386 was common in the late 1980s and 1990s, particularly for games and software that
See also: Expanded Memory Specification (EMS), XMS (eXtended Memory Specification), HIMEM.SYS.