Re: Multi-threading

["James W. Kilgore" <qappdsn@xxxxxxx>]

Larry Bolhuis wrote:

> Venu,
>
>   I heartily endorse Patricks suggestion to use a data queue.

<<snip>>

>
>
>   Many people don't realize the overhead required to start and stop jobs
> on the AS/400.

<<snip>>

I'll second that one Larry.  Good point.

When I first read your post Venu, I too thought "change the jobq" as many 
responses
indicated.  It's a quick off the cuff answer.  But the data queue technique is 
a better
solution.  If you are producing a report, let's say a pick slip, for each 
record being
processed, you can open and close the spool file for each data queue entry 
processed
and essentially have document on demand processing.

Not only do you save on job initiation time, but also on any additional file 
open/close
and have a better handle on CPU utilization and overall job management.

One more thing, when we mapped our data queue entry, we added a "verb" field 
which
could contain a *END value to do a graceful program end.  There are other verbs 
we
could send to the program such as modification of timeout period so the program 
could
be shifted from demand mode which required open/close for each entry to batch 
mode that
would open once, run many then close.

As a side note, the thread about design shift will eventually get around to data
queues.  Eventually it will get to Rob Dixon's neural network.  The data queues 
are an
essential part of the "closed" feedback system I mentioned earlier and are one 
of the
methods for providing feedback to a learning system that can alter behavior on 
the
fly.  If you've followed the thread at all, there was mention to dynamic HTML 
as a
screen painter and how a browser would have to test every refreash for replaced
format.  A data queue could inform a program when a change occured therefore the
overhead of an "every refreash" test could be eliminated and do away with the 
overhead
cost of constantly checking for timestamp on a panel format.  But that's for 
another
post ;-)

James W. Kilgore
qappdsn@ibm.net


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