Re: [Tcllib-devel] Distributed computing anyone?

[Andreas K. <and...@ac...>]

> Hello all,
>
> Michael Schlenker and I were just discussing a possible new are of interest
> in Tcllib: distributed computing.
>
> First of all, let me explain what the two of us mean by "distributed
> computing":
> Two or more programs (either running on the same computer or on different
> computers) share information, so that they can both progress in their task.

> Examples:
> - The tkchat is such a system - a whole bunch of people talking to each
> other.
> - SOAP is a well-known protocol that allows programs (processes) to share
>   information.
> - GRID computing where large-scale computational programs running
>   on all kinds of computers cooperate to predict the global climate for
> the next
>   100 years.

Note jcw's "Tequila" for shared arrays.
Note further Tcllib's "tie" (rarray backend) for doing same (foundation:
Tcllib's "comm").

> Mind you: we are not out to create something that will encompass all such
> forms of distributed computing!
>
> Let me outline our intended audience:
> The average programmer knows of multithreading and multiprocessing
> as powerful techniques to enhance the performance of their programs.
> Or they know of client-server techniques to allow several people to
> use their system. Multithreading is notoriously hard to get right.
> Client-server systems are much easier - if you use Tcl :).

In Tcl multi-threaded can be seen as client-server system running within a
single process (the apartment-model + thread::send).

> The programmers and users we envision do not have massive
> computer networks for doing their job. Just a couple of boxes that
> could be used in some biggish computation but right now it is too much
> work to get them cooperating.
>
> What if we had a framework where such people could plug in their
> various programs with only little adaptations. Tcl and Tcllib have
> a lot of tools for doing this. So all that is needed is a bit of
> infrastructure.

"comm" is the main infrastructure IMHO. The main thing will be to define how
tasks are communicated, results etc. That might be specific to the system used.
Security also becomes a much biger issue than before ... Reminds me, wanted to
write something to allow use of "tls::socket" in "comm".

> Given the variety of tools  (secure  connections or not for instance), that
> infrastructure could be tuned to their needs with just a few switches.

> I propose to discuss either on this list or on the Wiki the outlines of
> such an infrastructure and to go ahead and assemble it from the tools
> we have when there is enough clarity about it.

I have no trouble to have it discussed here.

It fits a bit with the (now defered) name-service thingy. The name server can be
used by the various pieces of the distributed system to find each other. Note
also Apple Bonjour/Rendezvous, it does a similar thing.


--
	Andreas Kupries <and...@Ac...>
	Developer @ http://www.ActiveState.com
	Tel: +1 778-786-1122