continue about hide file, a question cause by dos command

Hi, everybody:
I can hide files under windows. but i find a problem. for example: i
have hide a.txt, I cannot see it under windows,and use dos command dir or
tree can not see it also, but if I type dir /s a.txt, this command will
display a.txt. what cause this problem occur? can somebody tell me? thank
you!

thank you !
i recieved your reply for my question about hide file. thank you at first.
but i cannot see it at www.osronline.com .and i lost your mail too,
so…

my question is can you tell me more detail about this problem? because i
am weak about this field.
from where i can find the status_buffer_overflow? return value by
KeWaitForSingleObject?

appeciate!