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Diffstat (limited to 'BUILD/Help/html/advanced/DaylightSavingTime.html')
| -rw-r--r-- | BUILD/Help/html/advanced/DaylightSavingTime.html | 71 |
1 files changed, 34 insertions, 37 deletions
diff --git a/BUILD/Help/html/advanced/DaylightSavingTime.html b/BUILD/Help/html/advanced/DaylightSavingTime.html index 4fffe036..b29a612a 100644 --- a/BUILD/Help/html/advanced/DaylightSavingTime.html +++ b/BUILD/Help/html/advanced/DaylightSavingTime.html @@ -3,9 +3,9 @@ <HEAD> <META HTTP-EQUIV="CONTENT-TYPE" CONTENT="text/html; charset=windows-1252"> <TITLE></TITLE> - <META NAME="GENERATOR" CONTENT="OpenOffice.org 3.0 (Win32)"> + <META NAME="GENERATOR" CONTENT="OpenOffice.org 3.2 (Win32)"> <META NAME="CREATED" CONTENT="20091208;20054200"> - <META NAME="CHANGED" CONTENT="20091211;18381300"> + <META NAME="CHANGED" CONTENT="20100902;19275000"> <META NAME="Info 1" CONTENT=""> <META NAME="Info 2" CONTENT=""> <META NAME="Info 3" CONTENT=""> @@ -17,53 +17,50 @@ H2 { margin-bottom: 0.21cm } H2.western { font-family: "Arial", sans-serif; font-size: 14pt; font-style: italic } H2.cjk { font-family: "MS Mincho"; font-size: 14pt; font-style: italic } - H2.ctl { font-size: 14pt; font-style: italic } + H2.ctl { font-family: "Mangal"; font-size: 14pt; font-style: italic } A:link { so-language: zxx } --> </STYLE> </HEAD> -<BODY LANG="de-DE" DIR="LTR"> +<BODY LANG="en-US" DIR="LTR"> <H2 CLASS="western" STYLE="font-style: normal"><FONT FACE="Tahoma, sans-serif">Daylight -saving time</FONT></H2> +saving time <SPAN STYLE="font-weight: normal">(Windows)</SPAN></FONT></H2> <P STYLE="margin-bottom: 0cm"><BR> </P> +<P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, sans-serif">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.</FONT></P> <P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, sans-serif">The -Windows operating system exhibits quite a unique behavior when -handling timestamps on NTFS file systems. This leads to a well-known -issue that all file synchronization software has to handle:</FONT></P> -<P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, sans-serif">During -daylight saving time switching, (local) file times are shifted by one -hour on NTFS file systems, while NO shift occurs on FAT/FAT32 drives -(as used by most USB sticks)! Thus when synchronizing an NTFS against -a FAT32 volume file times become asynchronous twice a year!</FONT></P> +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.</FONT></P> +<P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, sans-serif">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.</FONT></P> +<P STYLE="margin-bottom: 0cm"><BR> +</P> <P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, sans-serif">For a -comprehensive discussion about this issue refer -to:<BR><A HREF="http://www.codeproject.com/KB/datetime/dstbugs.aspx">http://www.codeproject.com/KB/datetime/dstbugs.aspx</A></FONT></P> +detailed discussion about this issue refer to: +<A HREF="http://www.codeproject.com/KB/datetime/dstbugs.aspx">http://www.codeproject.com/KB/datetime/dstbugs.aspx</A></FONT></P> <P STYLE="margin-bottom: 0cm"><BR> </P> <P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, sans-serif"><B>Solution:</B></FONT></P> -<P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, sans-serif">In -order to avoid re-copying files that have a modification time -difference of +-1h FreeFileSync offers a global option: <I>Menu -> -Advanced -> Global settings: Ignore 1-hour file time difference</I>.</FONT></P> -<P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, sans-serif">If -"<I>Ignore 1-hour file time difference</I>" is checked, all -files with a +-1h difference are treated as having the same time. -This also handles different file time precisions (NTFS: 100ns, -FAT/FAT32: 2 seconds) by allowing a 2 second tolerance .</FONT></P> -<P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, sans-serif">Files -that have a deviation of less than one hour are categorized as -conflicts. The reasoning is that these files surely have been -modified on at least one side since last synchronization. But during -one of the two daylight saving time switches per year the older file -is shown pretending a newer date which can lead to data loss (when -using the rule to overwrite older with newer files).</FONT></P> -<P STYLE="margin-left: 1.46cm; margin-bottom: 0cm"><SPAN ID="Rahmen1" DIR="LTR" STYLE="float: left; width: 80%; height: 0.14cm; border: 1px solid #000080; padding: 0.05cm; background: #ccccff"> - <P ALIGN=LEFT STYLE="margin-left: 0.79cm; margin-right: 0.98cm; margin-bottom: 0cm"> - <FONT FACE="Tahoma, sans-serif"><B>Note:</B><BR>If synchronization - takes place between NTFS ↔ NTFS or FAT32 ↔ FAT32 this - checkbox provides no advantage and can be left unchecked.</FONT></P> -</SPAN><BR CLEAR=LEFT><BR> +<P STYLE="margin-bottom: 0cm"><FONT FACE="Tahoma, sans-serif">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.</FONT></P> +<P STYLE="margin-bottom: 0cm"><BR> </P> </BODY> </HTML>
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