Expanded Memory Specification

(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)].

{LIM EMS 4.0 spec

(ftp://ftp.intel.com/pub/PCandNetworkSupport/FAQs-Self-Help_Docs/SPEC.E