Re: Procedures, Modules, Service Programs

Hi, Birgitta:

The main problem with binding many modules into a single large service program is that you force the system to activate the entire large service program "all at once" -- the more procedures it has, the longer this process will take. By keeping service programs smaller, with relatively fewer procedures per service program, you can keep this overhead to a minimum.

Note, however, that If service program A uses a procedure in service program B, then when A is activated, this will cause B to be immediately activated, too, and so on, down the line (if B uses procedures in C, and so on). This process can add significantly to the "overhead" associated with activation.
At V6R1, IBM implemented the ability to delay activating other service programs until they are actually needed (when any procedure in that *SRVPGM is first called). You must specify a new *DEFER option on the BNDSRVPGM parameter of the CRTSRVPGM command to take advantage of this new feature. For details, see:

http://publib.boulder.ibm.com/infocenter/iseries/v6r1m0/topic/cl/crtsrvpgm.htm

This could be beneficial if you have many small *SRVPGMs that use procedures in many other small *SRVPGMs, and you are running V6R1.

All the best,

Mark S. Waterbury

> Birgitta Hauser wrote:

Hi guys,


I'm just curious and I'd like to know how to handle it:

Procedures, Modules, Service Programs and Programs


(We just had some discussions about it).

Currently I'm using several procedures within a single module (grouped
according functionality).

To make it easy I normally create a service program for each module
(exceptionally I also bind several modules with generic names for example
Date* into a service program).

Into a program only a single module gets bound and I never export procedures
from a program module.


An colleague argues having a lot of service programs is not good, he insists
in having a single service program with all modules for the whole
application, because there will be only a single activation.

I don't like this idea, because: If I only want to use a string function for
my batch program all display and printer file and what else functions must
be activated.


I just like to know how you handle it and why.


Mit freundlichen Grüßen / Best regards


Birgitta Hauser


"Shoot for the moon, even if you miss, you'll land among the stars." (Les
Brown)

"If you think education is expensive, try ignorance." (Derek Bok)

"What is worse than training your staff and losing them? Not training them
and keeping them!"