the ._ files are where osx puts the resource fork of a file if it's not on a HFS or HFS+ volume, eg, UFS, or Fat16/32 or NTFS (or any of the linux file systems) Only way to not have these on a non HFS file system is to not have resource forks, which isn't hard with files. they SHOULD be created without them. if you gives files a different application to open with than the system setting, or if images have a thumbnail of themselves as the icon, etc, that will require a resource fork.
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