@ Julius Werner
Thank you very much for valuable information. It will save my time very much. And it urged me on.
While I was searching various things, I started to feel that Google might be very serious at least about security, Chrome OS might be quite more secure than starting learning other GNU/Linux distributions because I am a noob. I still have some complicated feelings for Google, though. Because I do not know well yet, but Google has not a decent customer services is a fact. I like the approachs to security, but I cannot like the attitude toward customers.
Anyway I am happy now. I think I would start trying Chromium OS after a while. It would be so much fun. As the starting point of my play on computers, it seems to be proper. I could draw the map. Thank you for other clues on the map, too. I only have glanced at the links. Those were almost completely unable to understand.
If my questions oberflowed much again, please let me ask you hackers here questions again. Somehow I trust your words strongly, maybe because of your writing style. I got to know what I do in front of my lovely laptop so I am excited. Applying update would be my first job. Thank you very much.
Sincerely,
Masaru Suzuqi