From 88a8b528e20013c0aa3cc6bcd9659b0b5ddd9170 Mon Sep 17 00:00:00 2001 From: Daniel Wilhelm Date: Fri, 18 Apr 2014 17:20:07 +0200 Subject: 5.4 --- BUILD/Help/html/DaylightSavingTime.html | 80 --------------------------------- 1 file changed, 80 deletions(-) delete mode 100644 BUILD/Help/html/DaylightSavingTime.html (limited to 'BUILD/Help/html/DaylightSavingTime.html') diff --git a/BUILD/Help/html/DaylightSavingTime.html b/BUILD/Help/html/DaylightSavingTime.html deleted file mode 100644 index a15ea521..00000000 --- a/BUILD/Help/html/DaylightSavingTime.html +++ /dev/null @@ -1,80 +0,0 @@ - - - - - - - - - - - - - - - -

Daylight -saving time (Windows)

A -common problem synchronization software has to deal with 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 happening -with USB memory sticks. Files that previously appeared to be in sync -are now shown with an one hour modification time offset, although -they have not been modified by the user or by other means.

The -reason for this strange 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 -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.

For a -detailed discussion about this issue refer to: -http://www.codeproject.com/KB/datetime/dstbugs.aspx

Solution:

Luckily -FreeFileSync users need not to worry about this issue. 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 -travel between different time zones.

Note:

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 additional meta data is written for - each file.
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