Expanded Memory under Windows 3.0
ID: Q51737
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The information in this article applies to:
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Microsoft Windows versions 3.0, 3.0a
SUMMARY
In Windows versions 3.0 and 3.0a, Windows no longer uses expanded memory
for the advantage of Windows applications except in real mode.
MORE INFORMATION
Expanded memory management under Windows 3.0 or 3.0a is handled as follows.
Real Mode
Real mode Windows 3.0/3.0a uses expanded memory in the same manner as
Windows/286 versions 2.1x.
When Windows runs in real mode, expanded memory may be provided by the
following:
- On 8088/80286 machines, an expanded memory board's driver, which
is the only genuine method to obtain LIM standard expanded
memory on these processors. However, of course, we recommend
reconfiguring the board as extended memory if it is being used
on a 286 machine and expanded memory is not absolutely required
by an MS-DOS application.
- On 386 machines, the Microsoft EMM386.SYS driver, included with
the Windows 3.0/3.0a package, which converts 386 extended
memory to expanded via the special capabilities of the 386
processor.
286 Protected Mode
When Windows runs in 286 protected mode, expanded memory may be provided by
the following:
- On 286 machines, an expanded memory board's driver, as above. In
this case, Windows doesn't use the supplied expanded memory because
Windows is running in protected mode. However, expanded memory may
be used by MS-DOS applications running before, during, or after
Windows.
- On 386 machines, the Microsoft EMM386.SYS driver. Here, any
extended memory converted to expanded by EMM386.SYS prior to
running 286 protected mode is unavailable to Windows. Additionally,
expanded memory may be allocated by an application or driver via
EMM386.SYS prior to running Windows and not cause problems.
386 Enhanced Mode
In 386 enhanced mode, expanded memory may be provided by the following:
- Windows, which provides expanded meory emulation for MS-DOS
applications running under Windows in 386 enhanced mode virtual
machines.
- If expanded memory is also required outside of Windows/386
enhanced mode, it may be supplied in one of two forms depending
on the requirements of the application/driver that needs
expanded memory:
- By the Microsoft EMM386.SYS driver (in a manner similar to
that noted above)
- or -
- By the Windows/386 enhanced mode WINSTART.BAT feature. If
Windows enhanced mode detects that a WINSTART.BAT batch file
is present in the path when Windows is executed, the following
procedure is performed:
- Loads the Windows/386 enhanced mode memory management,
including expanded memory emulation.
- Runs WINSTART.BAT, allowing any programs or drivers
executing therein to use the emulated expanded memory
loaded in Step 1. This may include starting a network
that loads network drivers in expanded memory.
- Loads the Windows interface.
NOTE: WINSTART.BAT is simply a means of loading some programs in
Windows that can use expanded memory. It doesn't provide expanded
memory, it just allows you to run programs that want to use it.
Additional query words:
3.00 3.00a
Keywords :
Version : WINDOWS:3.0,3.0a
Platform : WINDOWS
Issue type :
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