DOCUMENT:Q82418 01-OCT-1999 [win95x] TITLE :32-Bit Disk Access and Portable Computers PRODUCT :Microsoft Windows 95.x Retail Product PROD/VER:WINDOWS:3.1,3.11 OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows versions 3.1, 3.11 ------------------------------------------------------------------------------- SUMMARY ======= 32-Bit Disk Access should not be used on battery-operated portable computers that implement power-saving features. Enabling 32-Bit Disk Access on such machines can cause Microsoft Windows version 3.1 to stop responding (hang). MORE INFORMATION ================ Enabling 32-Bit Disk Access causes Windows to access the system's hard disk(s) using an Enhanced mode virtual device driver (VxD), which accesses the controller hardware directly. To function correctly, the disk controller must be completely compatible with the standard Western Digital hard disk controller architecture. In most cases, Setup and the VxD's own initialization code properly detects those controllers that are not 100% compatible with the Western Digital standard. The disk controllers used in portable computers are very similar to Western Digital controllers but have extensions used for power management, such as shutting down the disk drive when it hasn't been used for a while or when the machine is placed in suspend mode by the user (typically by pressing a button). Some machines, such as Tandon notebook computers, change the state of the disk controller when the power source is changed from line to battery. Basically, the power management support can change the state of the disk controller without notifying Windows. Since there is no standard for this hardware, the 32-Bit Disk driver cannot determine when power-management events have occurred or what to do about them. If the driver determines the controller is in a different state than it expected, it will produce an error message. If this message is encountered, 32-Bit Disk Access should be turned off. If Windows cannot be started in Enhanced mode while 32-Bit Disk Access is enabled, Windows should be started with the command line, WIN /D:F The switch temporarily disables 32-Bit Disk Access. 32-Bit Disk Access should then be turned off permanently by using Control Panel's Virtual Memory dialog box. Controllers that support drive spin-down, such as Compaq's 386N computers, should not use 32-Bit Disk Access for similar reasons. NOTE: To avoid problems with these machines, 32-Bit Disk Access is disabled by default. If the machine is not a portable and does not support spin-down, then 32-Bit Disk Access can be enabled. Additional query words: 3.10 32 fast disk lte/25c docking station lte Compaq 486N 3.11 laptop lap top fastdisk ====================================================================== Keywords : Technology : kbWin3xSearch kbZNotKeyword3 kbWin310 kbWin311 Version : WINDOWS: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.