Re: Poison

["Beton, Richard" <richard.beton@xxxxxxxxxx>]

"Campbell, John" wrote:

> Let's get back to basics, for a moment, rather than argue the
> merits of exception syntax.  The central issue is how do you manage
> a network of large numbers of processes. Kill -9 is untennable if
> you need to kill 23 nodes of a 48 node network.  Let alone getting it
> right if have hundreds of nodes.
>
> What is the default behavior you want?  ...<snipped>...
> Now, if you dont want the default behavior, you explicitly specify
> the behavior of the poison watchdog (commissar?).

I too had thoughts along these lines. For Java/JCSP it can be written, but
with some quite significant code overhead.
For occam the situation is possibly worse. One of occam's strengths is that
it is purely WYSIWYG. We're talking about
having a shutdown feature that is either

a) hand-coded, verbose, error-prone and hard to test. :-(   But doggedly
WYSIWYG. :-)

b) added by the compiler or by some other clever tool, in which case it
ceases being WYSIWYG.

In case (b), because we're only talking about shutdown behaviour, not the
normal program flow, is losing the WYSIWYG
property a serious problem? Perhaps not. Interestingly, it might form a
basis for a generalised exception handling
mechanism. I don't quite understand why it is felt that this is such a bad
thing. Did I miss something?

Rick



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