Re: Service programs

<Booth>Why would one use a service program instead of a stand-alone program? and the opposite?</Booth>

A Programm is needed, whenever you need a main procedure (to call the programm from out of the world). As a conclusion of this: your application is needing one or more programms.

From a technical perspective programms could call other programms on as400

very easy (you don't need job controll to do so), so there is no need to have SRVPGMs. The performance advantage of bound calls compared to programm calls is neglectable in real world, so you might be happy with programms only. But (!!!) your application design and readability of your code will have great benefit from using SRVPGMs. Some important points:

- subprocedure names are not limited to 10 chars, so you could use meaningfull names.
- subprocedures allow to take full controll over parameters checked by the compiler.
- grouping sub procedures into SRVPGMs reduces the number of objects (PGMS and SRVPGMs) to deploy.
- grouping subprocedures into SRVPGMs could help to reuse code instead of inventing the wheel over and over again.
- subprocedures could hae a returnvalue - good for readability.
- SRVPGMs have multiple entry points, so Sub Procedures could share statefull variables, reducing the number of parameters to pass.
- SRVPGMs could be used to hold statefull data, reducing the complexity of programms by modularizing.

D*B