Memory and MS Windows Standard Mode


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STANDARD MODE WINDOWS 3.00
==========================

Breaking the 640K barrier on 286 machines

Standard Mode and Conventional Memory
-------------------------------------

When standard mode Windows 3.00 is executed, it adds the amount of
free conventional and extended memory and looks at the total amount as
one contiguous block of memory. Conventional memory has no special
meaning under standard mode, except when running DOS applications.
Running real or standard mode Windows 3.00 has the same DOS
application support, and DOS applications must run within conventional
memory.

Standard Mode and the 384K Reserved I/O Address Space
-----------------------------------------------------

Windows 3.00 does not access the 384K reserved I/O address space
directly in standard mode. Still, if a physical expanded memory board
is present, the board's EMM will use areas of the 384K reserved I/O
address space. If you suspect a 384K reserved I/O address space
conflict is causing a problem, temporarily remove the external EMM for
testing purposes.

Standard Mode and Expanded Memory
---------------------------------

Standard mode Windows 3.00 does not use expanded memory at all. DOS
applications running under standard mode can access expanded memory
only if a physical expanded memory board along with the appropriate
memory manager is present in the machine. Compatible 386 Expanded
Memory Managers such as EMM386.SYS can be loaded to provide expanded
memory outside of Windows. However, 386 Expanded Memory Managers
cannot be used to provide expanded memory to DOS applications running
from standard mode Windows. The 386 Expanded Memory Manager will be
disabled when standard mode loads. See the "Expanded Memory for DOS
Applications" section of this application note for more information on
using EMS with standard mode.

Standard Mode and Extended Memory
---------------------------------

Windows 3.00 standard mode can access extended memory directly. It
adds the free conventional memory and free XMS extended memory. It
then provides the total as memory for Windows applications to use
(minus the memory required by standard mode Windows itself). Standard
mode initially accesses extended memory through the XMS driver
HIMEM.SYS. DOS applications that use XMS memory can also be run from
standard mode Windows. Since standard and real mode Windows both use
the same DOS application support, the same restrictions apply (see the
"Real Mode and Extended Memory" section of this application note).












ms-windows