You might encounter certain scenarios where you have either VB6 applications that used information from an AS400 box or new .NET applications that need to get information in or out the AS400 box.
Usually this is done by creating RPG programs that generate plain text files that are transfered to PCs and processed by the VB6 or VB.Net application.
But would't it be great to access the AS400 directly, perform queries, execute programs, even use the AS400 users print jobs and other services.
IBM has a project call JTOpen, this is an open source java implementation of objects that allow you to access the AS400 box. http://www-03.ibm.com/servers/eserver/iseries/toolbox/downloads.html
So why is this useful to you? This is in Java, what help could it give you? Because there is another interesting project called IKVM.
I already posted about this project see my post on IKVM for more details.
With IKVM you can generate an assembly and use it in your projects.
You can start using this functionality directly in any of your VB.NET or C# projects.
If you have a VB6 applications, what are you waiting for: upgrade it now to VB.NET or expose this functionality thru a simple COM object and use it in VB6.
I'll post about this technique one this days.
And now enjoy accessing your AS400 from .NET
Regards