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 |
|