usually after doing my work I run a script to create backup on hardisk and another on my thumb drive . what the script do is

rm -f mywork.old
cp -f mywork.tar mywork.old
tar cvf mywork.tar pathtomywork/
cp -f mywork.tar /media/disk/backup/mywork.tar

as you see very simple .

when I done today backup and check the datetime on dolphin I found the date time never change still show my last (yesterday) datetime .
I run my backup script again and check and find that still the same . so I go to konsole and run "ls -l" .

the file in konsole show the new datetime .

I think kde4 is far from stable .