[Pipet Devel] BL PL design documentation

Brad Chapman chapmanb at arches.uga.edu
Mon Sep 11 17:28:48 EDT 2000

Jarl wrote:
>  As promised I've made a draft about the BL & PL design. Please
>  supply me with anything you can think of that I missed, so I can
>  finalize the document soon.

This looks really nice Jarl. Thanks for writing this up so clearly and

I just have one question about it all:

You only mention briefly the idea of the centralized name-server that
Piper has to connect with to know about other Piper instances on the net.
>From your listing of tasks, it appears as if you would like the BL to be
the place where all of this communication occurs, and hence the place
where the name-server stuff would be implemented. 

You only talk about KQML remote communication, so I'm not sure exactly
how this implementation will work. What are your thoughts on this?

I would like to argue that we give the DL the responsibility of finding
other available Piper instances, and then returning this info to the BL
(we could design an addition to the dl2bl.idl interface to handle the BL
requesting the info from the DL). I think this is good for a couple of

1. This way we can write and prototype the whole thing in python, which,
IMHO, is very nice for designing CORBA stuff in. I'm quite worried about
fighting with C++ memory issues, especially for a long running

2. I'm a little worried about the BL becoming huge and unweildy if it
gets assigned a ton of tasks (it already has communicating with the DL
and BBL, doing node splitting, GA stuff, using KQML to communicate with
remote BLs).

3. I think this is a nice separation between "high-level" remote
communication (ie. finding out what other Piper programs are out there)
versus "low-level" remote communication (ie. querying for getOutput()

What do you guys think? Am I completely off the wall, or does this make
some sense?

Jeff wrote:
>  Also, do you really want to call these components "Grandma, Mother,
>  and Baby"?	It's perhaps a little corny :-)  I would prefer "Primary,
>  Secondary, and Tertiary".	Then you can abbreviate them "PBL, SBL,
>  TBL" or "BL1, BL2, and BL3" or whatever.

Nah, you can give my +1 to keeping the "family names." Not only is it
more descriptive of what is going on, it is also a heck of a lot more
interesting, even if it may be a bit corny :-). Man, if we can't be a
little corny, what else do we have left?


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