System integrators are typically responsible for migrating the CICS, IMS and JCL applications from the mainframe. They download the applications to the Windows or UNIX environment, and leave you with a working application, running under Enterprise Server.
In some cases the system integrators might use Micro Focus migration tools including Enterprise Developer to migrate your CICS or IMS applications. They replace one mainframe-only language or technology at a time, and make sure that the application works correctly before continuing. For example, if your application includes Assembler and PL/I modules, they might replace the Assembler modules with COBOL modules. They would then recompile and test the application thoroughly before moving on to replace the PL/I modules.
When the system integrators have got the application up and running under Enterprise Server, they hand over to you to maintain and develop the applications in Enterprise Developer, and to run the applications under Enterprise Server.
This book assumes that your application has been migrated from the mainframe, and that it runs successfully under Enterprise Server.