DOCUMENT:Q163880 08-AUG-2001 [winnt] TITLE :COPY Command Causes File Cache to Grow PRODUCT :Microsoft Windows NT PROD/VER:winnt:4.0 OPER/SYS: KEYWORDS:kbnetwork ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Windows NT Workstation version 4.0 - Microsoft Windows NT Server version 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== When you use the COPY command of Cmd.exe to copy files that are significantly larger than the physical memory, Windows NT appears to slow down and user interface performance decreases. When you look at this in performance monitor, the cache is very large (from 50 to 90 percent of physical memory) and the process working sets have shrunk. MORE INFORMATION ================ The CreateFile API has a flag (FILE_FLAG_SEQUENTIAL_SCAN) that is useful when copying files. It tells Cache Manager to not grow the file cache when requests for this handle arrive. Therefore, Memory Manager does not have to shrink the application's working set to accommodate the larger cache. The CopyFile and CopyFileEx APIs make use of this flag. Although the COPY command uses the CopyFile API, it opens the file without the mentioned flag first to inspect the source and destination files. WORKAROUND ========== Use XCOPY, File Manager or Windows Explorer to copy large files. RESOLUTION ========== To resolve this problem, obtain the hotfix mentioned below. STATUS ====== Microsoft has confirmed this to be a problem in Windows NT version 4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces): S E R V P A C K Additional query words: ====================================================================== Keywords : kbnetwork Technology : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400 Version : winnt:4.0 Issue type : kbbug ============================================================================= 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 2001.