problem with open command

From: aneel (anilpavankumar_at_yahoo.com)
Date: 03/10/04 

Date: Wed, 10 Mar 2004 06:20:17 -0600

here is the code i am using for open..
 

open(asd,write,OS),
write(hai),
close(OS).
it replies with no
what is wrong in it how do i make this to work.....plz help me......