Updated: 11/13/2018 by Computer Hope

EMS and EEMS may refer to any of the following:


1. Short for emergency management services, EMS is a way of accessing the Microsoft Windows bootloader through a RS-232 serial console interface using either bootcfg or bcdedit.

2. When referring to memory EMS and EEMS is an extended portion of memory. Below is additional details about all extended memory on computer running Microsoft operating systems.


A competing standard to EMS is EEMS, developed by Ashton-Tate, AST Research and Quandram.

Extended memory

Extended Memory is not configurable and unavailable to programs other than those that run in Microsoft Windows and OS/2.

Expanded memory

Expanded Memory utilizes EMS and allows DOS programs and other programs to take advantage of the available memory above 1 MB.

EMS (expanded memory specification)

Short for expanded memory specification, EMS is a specification that allows IBM compatible computers to access more than the 1 MB. Early IBM compatible computers running MS-DOS used 640 KB (conventional memory) + 384 KB (upper memory) = 1024 KB or 1 MB total memory for MS-DOS programs. EMS allowed computer programs to access memory above that 1 MB. However, due to of out of memory issues still being encountered by users, LIM EMS was created.

XMS (extended memory specification)

Developed by AST, Intel, Lotus, and Microsoft, XMS is short for extended memory specification and allows software access to more than one 1 MB.

Computer acronyms, DPMI, EMM, EMM386.EXE, Himem.sys, LIM EMS, Memory terms, Protected mode