DOCUMENT:Q153296 TITLE :Write Cache on IDE/ATAPI Disks Is Not Flushed on Shut Down PRODUCT :Microsoft Windows NT PROD/VER:3.51 4.00 OPER/SYS:WINDOWS KEYWORDS:kbbug4.00 kberrmsg kbfix4.00 NTSrvWkst ntstop --------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Server versions 3.51 and 4.0 - Microsoft Windows NT Workstation versions 3.51 and 4.0 --------------------------------------------------------------------- SYMPTOMS ======== If your computer supports the shut down and power down feature, you may experience one of the following problems: - CHKDSK runs as your computer starts and reports a dirty volume. - A blue screen appears and displays the following message: STOP 0x0000007B (parameter, parameter, parameter, parameter) INACCESSIBLE_BOOT_DEVICE CAUSE ===== Recent versions of IDE/ATAPI hard disk drives include a write cache. This cache is normally flushed automatically depending on an algorithm by the hard disk manufacturer. On computers that support the shut down and power down feature, the power may turn off before the write cache is flushed. RESOLUTION ========== Windows NT 4.0 -------------- To resolve this, apply the fix mentioned below or wait for the next service pack. This hotfix has been posted to the following Internet location: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT40/ hotfixes-postSP3/ide-fix NOTE: The above link is one path; it has been wrapped for readability. Windows NT 3.51 --------------- To resolve this, apply the fix mentioned below or wait for the next service pack. This hotfix has been posted to the following Internet location: ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/usa/NT351/ hotfixes-postSP5/ide-fix NOTE: The above link is one path; it has been wrapped for readability. STATUS ====== Microsoft has confirmed this to be a problem in Windows NT version 4.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information. Microsoft has confirmed this to be a problem in Windows NT version 3.51. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information. MORE INFORMATION ================ The IDE/ATAPI specification does not define a command to determine if a write cache is present or to explicitly flush the cache. The Windows NT file system drivers modify the boot sector on startup to indicate a dirty volume. On shut down, the last operation is to modify the boot sector again to mark the volume clean. This last write is cached in the cache of the disk. If the power is removed too early, this sector is not written at all and the volume is still marked dirty. If the power disappears during the physical write to the disk, the boot sector is corrupt and the blue screen occurs. The fix to this problem is to send an IDLE command to the drive as the last command at shut down. This synchronous command ensures that the write cache is flushed. Additional query words: 3.51 4.00 ============================================================================ 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.