Starting with DOS 5 and Windows 3.0, EMM386 was an expanded memory manager (EMM) for 386s and up. It converted extended memory into EMS memory and allowed drivers and TSRs to be stored in the upper memory area (UMA) between 640K and 1M. Although EMS memory was required by some DOS applications, notably Lotus 1-2-3, and as PC memory increased and applications were modernized, this driver was no longer necessary. See
EMS,
UMA and
TSR.