AutoCAD 386 and Windows 3.0

• Microsoft Windows operating system versions 3.0, 3.0a

SUMMARY

AutoCAD 386 runs with Microsoft Windows version 3.00 in real mode only. This is because AutoCAD 386 uses VCPI (virtual control program interface) to access extended memory that comes into conflict with Windows in protected, standard, and enhanced mode.

MORE INFORMATION

The VCPI specification allows MS-DOS applications to directly access extended memory on 80386 machines. Windows 3.0 uses the DPMI (DOS protected- mode interface) specification. The DPMI specification allows DOS applications to directly access memory on 80286 and 80386 machines. Not all programs that use the VCPI specification are limited to running with Windows in real mode. Many programs, including Lotus 1-2-3 version 3.0, that use the VCPI specification run correctly in Windows protected mode.

The performance of an MS-DOS application that uses the VCPI specification depends on how closely the actual application follows the VCPI specification.

NOTE: When running AutoCAD under Windows 3.0 in standard mode, erratic functioning can occur. It is therefore recommended that you do not run AutoCAD while running in standard mode.

The AutoCAD product included here is manufactured by a vendor independent of Microsoft; we make no warranty, implied or otherwise, regarding this product's performance or reliability.