Re: Question about service programs

[Simon Coulter <shc@xxxxxxxxxxxxxxxxx>]

On 31/07/2008, at 10:42 PM, Adam Glauser wrote:

> I think that David might have the right idea, but not asking quite the
> right question.  To simplify David's case, lets suppose we have PGM0,
> consisting of modules MOD_0 and MOD_UTIL.  We also have PGM1,  
> consisting
> of MOD_1 and MOD_UTIL.
>
> If I now run PGM0 which calls PGM1, wouldn't there essentially be two
> copies of the code for MOD_UTIL in memory?

In that case there are two copies of the same code because you have  
"bound by copy" but there are also two different programs loaded.  
You'll have the same effect if you bind a module into a service  
program and also into a program object. If both the program and the  
service program are invoked then you'll have two copies of the "code"  
active but that's a stupid approach. The only case I can think of  
where it makes sense to bind the same module(s) into multiple objects  
is for security routines.

However, that's not what he asked. He said "50 people using the same  
interactive program that weighs 40MB". That is one program used by 50  
users. In that case only one copy of the program code no matter who  
loaded it first nor whether the users are running in different main  
storage pools.


> I think this must be the
> case, since if I change MOD_UTIL and rebind PGM0 but don't rebind  
> PGM1,
> PGM1 will still use the "old" version of the MOD_UTIL code.

That's true but again, not what he asked.

Regards,
Simon Coulter.
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