Texas Instruments 4000M - Manual (Page 258)

Expanded Memory
Expanded memory conforms to the Expanded Memory
Specification (
EMS ) developed by Lotus/Intel/Microsoft ( LIM )
known as LIM-EMS . Your computer supports EMS
version 4.0.
Expanded memory is accessed by allocating an area
(usually 64 KB) of system memory between 640 KB and
1 MB (and between 256 KB and 640 KB when the
/O option
is used) as a “window.” Pages or segments of data are
passed to and from Expanded memory through this
window, which is called the page frame. The page frame is
divided into at least four physical pages of 16 KB each.
The total amount of internal memory above 640 KB can be
assigned to either Extended memory (
XMS ) or Expanded
memory ( EMS ), depending on your requirements and which
driver is installed.
n Note: MS Windows can use both XMS and EMS in 386
Enhanced mode when properly configured. Refer to your
Windows User’s Guide for details and instructions.
The Expanded Memory Manager included with MS-DOS
( EMM386.EXE ) manages the interface between the program
and Expanded memory, bringing data in and out through
the page frame as required.
Before you can use Expanded memory, you must install the
EMM386.EXE device driver as described in the next section,
“Memory Device Drivers.” You need not install the
Expanded memory driver if your application does not
support Expanded memory.
Memory Areas
F-4 Configuring Memory