当您有两个具有相同时间戳的相同文件时，Windows却说其中一个文件比另一个文件新，这意味着什么？怎么会这样？今天的超级用户问答帖子帮助困惑的读者解开了时间戳之谜。

今天的问答环节是由SuperUser提供的，SuperUser是Stack Exchange的一个分支，是一个由社区驱动的问答网站分组。

问题

超级用户读者WBT想知道Windows如何决定两个具有相同时间戳的文件中哪一个更新：

When Windows displays a dialog like this with matching time stamps, how does it determine which of the two files is newer?

At first, I thought Windows was comparing the date created attribute and using the result of that comparison to label one or the other as newer. If a file was copied into a particular location, it may have the creation date of when the copy was made rather than the creation date of the original file. However, after reproducing it with another file, the result of which one is newer seems to be the opposite:

The result is the same whether copying or moving the file:

And for background, the file in test2 is a previously made copy of the file in test1.

Windows如何决定两个具有相同时间戳的文件中哪一个更新？

答案

超级用户贡献者grawity为我们提供了答案：

Time stamps in the NTFS file system have a resolution of 100 nanoseconds (0.0000001 s). Even if the properties dialog shows the same rounded value, it could still be that the files were created within tenths of a second of each other.

Note: Most file systems measure times in μs or ns. FAT32 is a bit of a relic and rounds timestamps to two seconds.

Try one of the following methods to compare the full time stamps:

• wmic datafile where name=”c:\\foo\\bar.txt” get lastmodified

Via PowerShell:

• (Get-ChildItem c:\foo\bar.txt).LastWriteTime.ToString(“o”)

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图片来源：WBT（超级用户）