DOCUMENT:Q82440 01-OCT-1999 [win95x] TITLE :Windows 3.1 HIMEM.SYS and Windows 3.0 PRODUCT :Microsoft Windows 95.x Retail Product PROD/VER:WINDOWS:3.0,3.0a,3.1,3.11 OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows versions 3.0, 3.0a, 3.1, 3.11 ------------------------------------------------------------------------------- SUMMARY ======= Using the Microsoft Windows 3.1 HIMEM.SYS extended memory manager on an EISA system with more than 16 megabytes (MB) of memory can cause Windows version 3.0 to fail. MORE INFORMATION ================ Windows 3.0 standard and enhanced modes rely on the HIMEM.SYS driver to "screen out" memory on the machine above 16 MB. Windows 3.0 standard and enhanced modes do not work well with memory above 16 MB, and Windows 3.0 does not function correctly if it is allowed to "see" this memory. Failure to screen this memory can result in reboots, general protection (GP) faults, failures to start, or data corruption. In some cases, Windows 3.0 enhanced mode works correctly because the WIN386.EXE file from Windows 3.0 does some screening of its own. The greater-than 16 MB memory screening is disabled in the HIMEM.SYS driver included with Windows 3.1. Windows 3.1 standard and enhanced modes do not need this screening because both modes fully support more than 16 MB of memory. If it is necessary to have both Windows 3.0 and Windows 3.1 running on your machine, you should replace the automatically installed Windows 3.1 HIMEM.SYS driver with the Windows 3.0 HIMEM.SYS. Windows 3.1 standard and enhanced modes work correctly with the 3.0 version of the driver. However, remember that the HIMEM.SYS driver included with Windows 3.0 is limited to 16 MB of memory. Additional query words: 3.10 3.11 ====================================================================== Keywords : Technology : kbWin3xSearch kbZNotKeyword3 kbWin300 kbWin300a kbWin310 kbWin311 Version : WINDOWS:3.0,3.0a,3.1,3.11 ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1999.