Expanded Memory Specification
EMS
LIM EMS
<storage> (EMS) An {IBM PC} memory {paging} scheme enabling
access to memory other than {conventional memory} in {real
mode}.
{Expanded memory} is provided through a {page frame} of at
least 64 {kilobytes} in the {reserved memory} address region.
Access to this memory is provided by an {expanded memory
manager} (EMM) software. The EMM functions are accessible
through {interrupt} 67H.
In {8086} or {8088} based systems this is the only way to use
memory beyond conventional memory. In systems based on
{80286} or later, {XMS} and {HMA} provide alternative methods.
EMS was developed jointly by {Lotus}, {Intel}, and {Microsoft}
prior to 1988. Accordingly, this specification is sometimes
referred to as LIM EMS.
A complete discussion of EMS and programming examples can be
found in ["PC System Programming for developers", 1989, ISBN
1-55755-035-2 (Book only) and ISBN 1-55755-036-0 (Book and
diskette)].
{EEMS}, a competing expanded memory management standard, was
developed by {AST Research}, {Quadram} and {Ashton-Tate}.
See also {upper memory block}.
(1996-01-10)