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HISTORY
The Lotus/Intel/Microsoft Expanded Memory Manager was originally
a Lotus and Intel project and was announced as version 3.0 in the
second quarter of 1985 primarily as a means of running larger
Lotus worksheets by transparently paging unused sections to
bank-switched memory. Shortly afterward Microsoft announced
support of the standard and version 3.2 was subsequently released
with support for Microsoft Windows. LIM 3.2 supported up to 8
megabytes of paged memory. The LIM 4.0 supports up to 32
megabytes of paged memory.
AST/QUADRAM/ASHTON-TATE ENHANCED EXPANDED MEMORY SPECIFICATION
The AQA EEMS maintains upward compatibility with the LIM, but is
a superset of functions.
The AQA EEMS permits its pages to be scattered throughout the
unused portion of the machine's address space.
On August 19, 1987, the new version of the Expanded Memory
Specification (EMS) was announced by Lotus, Intel and Microsoft.
This new version of the specification includes many features of
the Enhanced Expanded Memory Specification (EEMS) originally
developed by AST Reserach, Quadram and Ashton-Tate, although the
three original sponsoring companies elected not to make the new
specification upward compatible with EEMS. AST Research says that
they will endorse EMS 4.0 without reservation.
The definitive document for the LIM-EMS is Intel part number
300275-004, August, 1987.
The page frame is located above the 640k system RAM area,
anywhere from 0A000h to 0FFFFh. This area is used by the video
adapters, network cards, and add-on ROMs (as in hard disk
controllers). The page frames are mapped around areas that are in
use.
See Also Programming Specifications Locating Func/40h Func/4Eh/00h Errors |
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