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Is there a software or a way to configure Windows 7 such that I could sync the time to a time server, but have my system's clock advanced by 10 minutes from the time server's time?

E.g. When synchronizing to a time server and the time server says the time is 07:00 AM, instead of synchronizing to 7:00 AM, the time that will appear in my system clock is 7:10 AM.

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Just curious - why do you wish to do this? :) Also, serious side question, do you control the time server or just the desktop? –  DMA57361 Feb 18 '11 at 8:36
    
@DMA57361 I prefer that the time I see in my clocks are advanced by 10 minutes (all the clocks in my house and my cellphone are advanced by 10 minutes from NIST's time). It's mainly a personal time management and organizational thing. It makes me avoid being late and makes me do stuff 10 minutes earlier. =) I know I could just sync once and advance the time in my computer by 10 minutes manually, but I prefer that my computer sync its time to NIST's time servers regularly. I don't control the time server, only the desktop. I'll be using NIST's time servers. –  galacticninja Feb 18 '11 at 8:52
    
Note that some network services can be a little picky about the clock times on the computers at either end of the connection. You'd probably be better off with setting the system time accurately and looking for a clock program which allows you to display the time 10 minutes ahead of the system time. –  Dave Sherohman Feb 18 '11 at 13:21
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@Dave Sherohman Know of any such clock programs? –  galacticninja Feb 20 '11 at 6:14
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1 Answer 1

up vote 2 down vote accepted

Use the SetTimeZoneInformation API I don't think MS have anticipated your need but it may be possible to define a custom time zone with a 10 minute offset. This article contains example data for replacing the timezone table - with a small amendment you could achieve what you want.


Update - here's what I gleaned from various MS documents

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\Afghanistan Standard Time]
"TZI"=hex:f2,fe,ff,ff,00,00,00,00,c4,ff,ff,ff,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00
"Display"="(UTC+04:30) Kabul"
"Dlt"="Afghanistan Daylight Time"
"Std"="Afghanistan Standard Time"

The above is an example registry entry. Note the TZI key and value

This [TZI] structure specifies information specific to the time zone.

Copy
typedef struct _TIME_ZONE_INFORMATION { 
  LONG Bias; 
  WCHAR StandardName[32]; 
  SYSTEMTIME StandardDate; 
  LONG StandardBias; 
  WCHAR DaylightName[32]; 
  SYSTEMTIME DaylightDate; 
  LONG DaylightBias; 
} TIME_ZONE_INFORMATION; 


Bias
Specifies the current bias, in minutes, for local time translation on this computer.
The bias is the difference, in minutes, between UTC and local time.
All translations between UTC and local time are based on the following formula.
UTC = local time + bias 

The above is for WinCE but I expect XP/Vista/7 have similar structure for TZI. This can be verified by decoding some existing registry entries and seeing if the structure matches.

A brave person could use Regedit to create new registry entries defining a new time-zone with a suitable TZI "bias" value. They could then set their timezone to the one just created.

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+1 for a creative solution. I'd be curious to know if it really works, though... –  sleske Feb 18 '11 at 10:39
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