9fans archive / 1998 / 10 / 7 /    prev next

From: Russ Cox rsc@pla...
Subject: [9fans] Communication using TCP
Date: Fri, 2 Oct 1998 11:20:08 -0400

IL preserves message boundaries, while TCP
does not.  So if you write a 0 byte message
over IL, then a 0 byte message goes across the wire.
If you write a 0 byte message over TCP, then
0 bytes (nothing) goes across the wire.

In a very simplified mental model, think of IL
as sending length<msg>, while TCP just sends msg.
So a 0 byte write in IL sends
	0<>
while TCP sends 

(nothing), so the other end doesn't know that you've
actually done the write.  

As for why you can only use 143, I'll bet most ports
work, but the ports you tried were already being 
handled by aux/listen.  Look in /bin/service/ to
see what ports are already in use.

Russ