7zip compressing the same file slightly different results

I am using 7za command line

File dfat_clist.xls in directory 2010_05_07

The same dfat_clist.xls in directory 2010_05_08

Zips are created in the same directory where the xls files resides

string pars = "a -tzip \"" + Path.Combine( SourceDir,ZipName) + "\" \"" + Path.Combine( SourceDir, Mask ) + "\"" ;

Parameters given to 7za are full paths for zip and xls. For some reason a couple of bytes are different A7 and A8 values for directories 2010_05_07 and 2010_05_8 respectively. How to achieve identic开发者_StackOverflowal results and out of curiosity what causes this problem.

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If I understand the question you have two identical XLS files in different folders and you want to know why the two 7zip'd files are different?

Assuming that you aren't storing the directory name in the zip then you've probably hit the same problem I had (see '7zip produces different output from identical input').

The accepted answer from Mofi might help.