COPY Command Causes File Cache to Grow (163880)
The information in this article applies to:
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Server 4.0
This article was previously published under Q163880 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):
| Modification Type: | Major | Last Reviewed: | 8/8/2001 |
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| Keywords: | kbbug kbnetwork KB163880 |
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