Maintenance and support of a host application (Host-Legacy, PL/1)

The legacy application running on the mainframe maps business processes related to shipment control. Shipment control allows letters that belong to the same shipping group to be sent to a recipient different from the one originally specified on the letter. In such cases, a cover sheet with the address of the desired recipient is placed in front of the letter. The original letter retains its original recipient and is not modified. The corresponding processes can involve business transactions, generally reusable modules, or batch programs. The latter typically represent regularly scheduled processing tasks that must be monitored and corrected in the event of an error. The application itself consists of a large number of programs or modules written in PL/1 and JCL, utilizes both a hierarchical and a relational database for data storage, and includes various additional components.