Re: vk_l4 -- CVS Setup

[Ian Duggan]

> Taking it a little further, if you want to get network transparent rpc
> into L4 (not that I know if that is realistic), you won't put
> networking inside L4, but define an rpc interface that takes, say, a
> message in some form and an hostname/servicename/URL (possibly in a
> numeric interned form). That rpc would be implemented by some hurd
> process communicating with the hurd pfinet. So you could get network
> transparent rpc and still use Hurd servers for doing the networking,
> dns lookups etc. L4 need only know if the target of an rpc is local or
> remote, and it wouldn't make much sense to put any more knowledge
> about network things into L4 than just the local/remote distinction.
> (if you think some more about it, L4 may not even need that).

Reading the L4 definition, the IPC mechanisms seem very specific to
machines with some sort of shared address space access. It think it
would be very difficult to extend the idea of network transparency to L4
without destroying it's simplicity. L4 is already doing a number of
memory tricks to keep context switching cheap between it's threads,
using segment registers and such, where possible.

Network transparent RPC definitely seems like a userspace candidate to
me. The RPC you are describing would be built as messages to some sort
of RPC server (L4 server) making use of the L4 ipc calls to communicate
the message to the server. All concepts of networking and such would be
strictly outside of the L4 kernel.

-- Ian

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Ian Duggan                    address@hidden
                              http://www.ianduggan.net