Which, until recently, was losing file metadata, like extended attributes (in very old tmpfs versions also the timestamps could have been truncated). Whenever

Which, until recently, was losing file metadata, like extended attributes (in very old tmpfs versions also the timestamps could have been truncated). Whenever exact file copies are desired, they must not pass through /tmp or through any other place where tmpfs is mounted, unless it is checked that the tmpfs version is new enough to preserve file metadata. (In multi-user computers, it was usual to copy a file through /tmp for copies between users, because that might have been the only place where both users had access.) Older versions of tmpfs did not support any extended attributes, then only certain system attributes were preserved, while all user attributes were deleted. Only one year or two ago tmpfs has been enhanced to preserve most extended attributes, with some size constraints. Many older systems still have tmpfs versions that lose the extended attributes.