About backup the system
 

I am going to backup EVERYTHING of the system to the tape, someone said I can ignore some of the directory, for example, /proc, /tmp, /.journal
and /.fsck

I am not familiar with the structure of linux, which directory is not really necessary to be backuped?

/proc should not be backed up. This is psuedo file system created on the fly by the kernel.
/tmp doesn't need to be backed up. These are just temporary files.
/sys should not be backed up. This is another psuedo filesystem that gives users information about devices.
/mnt usually shouldn't be backed up. It depends on what you have mounted there.
/media should not be backed up. It is for temporary mount points. Backing up a mounted CD or DVD would be a waste.

You may want to exclude some directories, such as some hidden directories such as $HOME/<user>/.thumnails/.
Some particulars may be different for different desktop environments, distro's and what you have installed. I have covered the main ones in the top paragraph.

Good Luck!