Subject: Re: How to: move TCP/IP stack user space?
To: Nitin Vijay Vairagare <>
From: Michael Richardson <>
List: tech-net
Date: 04/21/1997 11:44:35

  You haven't explained why doing this is a good thing. I didn't know
"we" wanted to do it.

  If you want to do anything, you should consider creating a virtual
user space (a fellow at HAL calls this the "Domain" space): something
that isn't in the kernel, but is still protected from the user space,
and is common to all user processes. 

  The user code is able to access the space through call gates or
something like that, but the domain code doesn't have to copy in/out
to get at the user space, and can do things like TCP checksums
directly from the user's buffer.

  Very high performance TCP applications benefit by getting rid of the
socket layer, and by retransmitting directly from the user space
buffers. Think multimedia HTTP servers.
  Note that: TCP moves, but IP stays priveledged. IP does mutate a lot.

  Parts of X servers also live in this space. 

  Obviously this is rather Mach like, and maybe people that want to do
this should just move to NetBSD over Mach.

   :!mcr!:            |  Network security consulting and 
   Michael Richardson |      contract programming
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