Thanks for your immediate response: It enlights me of some principles to access event driven programming library. But I can't imagine what the primitives you mentioned would like, can you give a breif list of them? Or, can you indicate what part of X window code that I can learn of how to build up my own event-driven library under UNIX? I wish it would not be too complicated since that Xlib and Xt stuffs are nightmares to me. @_@ Or, as I mentioned, I think knowing the procedure of: from NIC receives a network packet to application's blocked read() returns, will be helpful to me. Can you give a basic introduction on this or just refer what parts of kernel code that I should look at? To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message