--- SODA Noriyuki <soda@sra.co.jp> wrote:
> >>>>> On Fri, 11 Mar 2005 08:13:43 -0800 (PST),
> 	"Kamal R. Prasad" <kamalpr@yahoo.com> said:
> 
> >> IMHO, this work focuses on very limited
> application,
> 
> > Its application is program recovery 
> 
> But existing checkpointing systems already provide
> program recovery
> without the feature that the patch provides.
> 

Dragonfly already provides checkpointing, and I added
v little code on top of it. The only differentiating
factor is that I am doing minimal work in process
space -which can get corrupted due to a variety of
reasons.

> > -but the types of userland applications (if that
> is what you meant)
> > which can use this feature is not limited.
> 
> My point is that I don't think that the feature is
> useful.
> 

If you don't have a means to checkpoint & restore in
NetBSD yet -adding it can be useful for programs that
are prone to crashes, but want to re-use program
state/sockets/pipes etc..

> > If you want to use checkpointing for process
> > migration, that would require a substantial amt.
> of
> > work on checkpointing the kernel side of the
> process
> > aka the file descriptors, sockets, pipes etc..
> 
> Actually, there are already some checkpointing
> systems which do
> provide process migration of processes which do
> network communication
> (e.g. MPI).  And such systems don't need the kernel
> support like what
> you are expecting.

They would run into issues with protected mode access
-after migrating. But that is just a guess as I have
not implemented one.

> If you have any interest how they implement it,
> please read the source
> code of the following free software, for example:
> http://www.pccluster.org/score/dist/index.php
> --
> soda
> 
Sure will look at that.

thanks
-kamal


------------------------------------------------------------
Kamal R. Prasad
UNIX systems consultant 
kamalp@acm.org

In theory, there is no difference between theory and practice. In practice, there is:-).
------------------------------------------------------------


		
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