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Time Stamps Change When Copying From NTFS to FAT

This article was previously published under Q127830
SUMMARY
When you copy a file from a Windows NT file system (NTFS)drive to a file allocation table (FAT) drive, the time stampchanges to an even number of seconds.
MORE INFORMATION
File time stamps on FAT drives are rounded to the nearest twoseconds (even number) when the file is written to the drive. The file timestamps on NTFS drives are rounded to the nearest 100 nanoseconds when thefile is written to the drive. Consequently, file time stamps on FAT drivesalways end with an even number of seconds, while file time stamps on NTFSdrives can end with either even or odd number of seconds.

When files are copied from NTFS drives to FAT drives, somefile time stamp rounding has to occur; the file time stamp is rounded up tothe next even second.

To preserve exact NTFS file times, always copy files fromNTFS drives to other NTFS drives. If you are writing a program to comparefile times between NTFS and FAT drives, accommodate for the expectedrounding.

For example, when you compare time stamps between an originalfile in NTFS and a file in FAT, which is copied from NTFS, youwill see the following:

NTFS time stamp: 7 hours 31 min 0 sec 000.
FAT time stamp becomes 7 hours 31 min 0 sec 000.

NTFS time stamp: 7 hours 31 min 0 sec 001.
FAT time stamp becomes 7 hours 31 min 2 sec 000.

NTFS time stamp: 7 hours 31 min 1 sec 000.
FAT time stamp becomes 7 hours 31 min 2 sec 000.

NTFS time stamp: 7 hours 31 min 1 sec 999.
FAT time stamp becomes 7 hours 31 min 2 sec 000.
3.10 granularity partition
Properties

Article ID: 127830 - Last Review: 11/01/2006 04:39:00 - Revision: 2.1

  • Microsoft Windows NT Advanced Server 3.1
  • Microsoft Windows NT Workstation 3.1
  • Microsoft Windows NT Advanced Server 3.1
  • Microsoft Windows NT Workstation 3.5
  • Microsoft Windows NT Workstation 4.0 Developer Edition
  • Microsoft Windows NT Server 3.5
  • Microsoft Windows NT Server 4.0 Standard Edition
  • KB127830
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