Time Stamps Change When Copying From NTFS to FAT

 Last reviewed: March 21, 1995
Article ID: Q127830
The information in this article applies to:
  • Microsoft Windows NT operating system version 3.1
  • Microsoft Windows NT Advanced Server version 3.1
  • Microsoft Windows NT Workstation version 3.5
  • Microsoft Windows NT Server version 3.5

SUMMARY

When you copy a file from a Windows NT file system (NTFS) drive to a file allocation table (FAT) drive, the time stamp changes to an even number of seconds.

MORE INFORMATION

File time stamps on FAT drives are rounded to the nearest two seconds (even number) when the file is written to the drive. The file time stamps on NTFS drives are rounded to the nearest 100 nanoseconds when the file is written to the drive. Consequently, file time stamps on FAT drives always end with an even number of seconds, while file time stamps on NTFS drives can end with either even or odd number of seconds.

When files are copied from NTFS drives to FAT drives, some file time stamp rounding has to occur; the file time stamp is rounded up to the next even second. For example, if you copy a file with a time stamp of 13:34:23 from an NTFS drive to FAT drive, the files is stored on the FAT drive with a time stamp of 13:34:24.

To preserve exact NTFS file times, always copy files from NTFS drives to other NTFS drives. If you are writing a program to compare file times between NTFS and FAT drives, accommodate for the expected rounding.

KBCategory: kbusage
KBSubcategory: ntfilesys
Additional reference words: 3.10 3.50 prodnt granularity partition

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Last reviewed: March 21, 1995
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