From fe9eb89ebc1b3c33cbac00a3fa095a14faef9113 Mon Sep 17 00:00:00 2001
From: Daniel Wilhelm A
-common problem synchronization software has to deal with are +-1 hour
+common problem synchronization software has to handle are +-1 hour
file time shifts after a Daylight Saving Time (DST) switch has
occurred. This can be observed for example when a FAT-formatted
-volume is compared against an NTFS volume as frequently happens with
-USB memory sticks. Files that previously appeared to be in sync are
-now shown with a one hour modification time offset, although they
-have not been modified by the user or by other means.Daylight
-saving time (Windows)
+Daylight Saving Time (Windows)
The -reason for this strange behavior lies in the way NTFS and FAT drives +reason for this behavior lies in the way NTFS and FAT drives store file times: NTFS stores time in UTC format, while FAT uses local time.
When -times stored in these two different formats are compared, one format -has to be converted into the other first. In both cases Windows uses -the current DST status as well as current time zone information for +times of these two different formats are compared, one format +has to be converted into the other first. In either way Windows uses +the current DST status as well as the current time zone for its calculations. Consequently the result of this comparison is dependent from current system settings and in particular file times -that used to be the same can show up as different after a DST switch.
+that used to be the same can show up as different after a DST switch or when the time zone is changed.
For a
@@ -49,8 +48,8 @@ detailed discussion about this issue refer to:
Solution: Luckily
-FreeFileSync users need not to worry about this issue. Each file on a
+
+FreeFileSync automatically handles this problem by adding the missing time information. Each file on a
FAT volume automatically gets additional meta data encoded in its
creation date that enables a correct file time calculation. This not
only solves all DST issues but also time shifts that occur due to
@@ -62,7 +61,7 @@ travel between different time zones. In
order for FreeFileSync to start handling DST and timezone
differences, an initial full synchronization is required.
- Subsequent syncs will never show a time difference again.
If a FAT volume is scanned the
first time by FreeFileSync this will take longer than usual since
--
cgit