File Time Stamp Rounding Up Errors - Improved resolution ?

[Alan.B]

Are Windows file time stamps created with 10 mSec resolution ?
Windows supports %TIME% with 10 mSec resolution, and cscript can access such timers.

I find that the modified, created, and accessed time stamps shown in the xplorer2 display pane are always 1 or 2 seconds more recent than values reported when a file is selected and File Properties displayed.

Closer inspection suggests that xplorer2 never reports an odd number of seconds, but always rounds up to an even number (even if the initial value is even it still gets bumped up by a value of two).

e.g.  the Modified (and also the Accessed) stamps for desktop.ini are :-
xplorer2 reports :-  04/05/2009 08:17:30 -HSA-----
File Properties    :-  4 May 2009 08:17:28

I deduce from such observations that xplorer2 does NOT report the "Properties" value of 08:17:28 because,
it does not round up to an even value from 08:17:28 to 08:17:28,
but it rounds up from something like 08:17:28.25 to 08:17:30.

I am intrigued by the 2 second anomaly.

My special interest right now is analysing and improving the Windows start-up sequence.  For much of this I can make timing measurements to a resolution of 10 mSec, but File Modified time stamps I can only get with 1000 mSec resolution.  I can determine cause and effect from a sequence of time stamps for various files - but not if they are within the same 1000 mSec window

Please advise me - is it possible to get a file time stamp with 10 mSec resolution ?
Any clues would be appreciated.

Regards
Alan

[nikos]

from what you describe i gather that you are examining a FAT partition where time resolution is 2sec. See this from the docs for more details:

A file time is a 64-bit value that represents the number of 100-nanosecond intervals that have elapsed since 12:00 A.M. January 1, 1601 (UTC). The system records file times whenever applications create, access, and write to files. Not all file systems can record creation and last access time and not all file systems record them in the same manner. For example, on NT FAT, create time has a resolution of 10 milliseconds, write time has a resolution of 2 seconds, and access time has a resolution of 1 day (really, the access date). On NTFS, access time has a resolution of 1 hour.

[Alan.B]

Thank you Nikos

I forgot to say I am using xplorer2 version 1.7.1.4 LITE under Windows XP Home with SP3, and C:\ is formatted NTFS.

All the xplorer2 time stamps show an even number of seconds,
but the file properties have a resolution of one second (i.e. half the files have an odd number of seconds.)

Thank you for your quote.
I selected the second line, and Googled, and the first hit took me to the relevant page at
http://social.microsoft.com/Forums/en-U ... ae75e316d8

I now know that file time stamps have a resolution much finer than 1 second intervals.  Actually accessing that information may be a problem, but I now know the information is recorded and it is worth searching for how to retrieve it.

Many thanks
Alan

[nikos]

strange, on my NTFS i can see 1-second resolution...
anyway the best xplorer2 can give you is this second resolution, for more details you will have to do some programming, eg with the windows scripting host

[Alan.B]

On my system the Comodo Firewall has 335 *.png etc files which get updated every hour.  When it happens they are all tweaked simultaneously.
The time stamps range from 14:45:08 through to 14:45:14 - and every one has an even number of seconds.  More than 40 files were tweaked every second, but xplorer2 shows over 80 at 14:45:08, and another 80 at 14:45:10, but none at 14:45:09.

I can live with it.  I did not start this thread to complain.  I simply observed a discrepancy that suggested rounding errors upon fractional seconds, which gave me hope that file times were available with resolution much better than 1 second.

Thank you for your scripting host link - I have now bookmarked it

Regards
Alan