The customer is responsible for the consumption-based billing of heating and water costs for landlords and tenants. The company also produces and assembles devices and systems for recording the consumption of energy and water in residential and commercial buildings.

• IBM Mainframe with the operating systems z/VM and z/VSE
• Linux Server, UNIX, and Windows workstations
• Database system DL/I and Db2/VM as well as Db2/LUW

The hierarchically-oriented database system DL/I is to be replaced by the relational system Db2 to meet the constantly growing business requirements. By expanding business activities abroad, flexibility and a new strategic direction are the primary goals. The previous static and DL/I-based applications no longer met these requirements. By switching to a relational database with all the advantages of a relational model, the future should be built. A possible complete migration of the mainframe to new systems is also planned.

The daily changes to the DL/I databases are recorded by tcVISION in real time both online and batch and saved in a staging Db2 database. In this database the data is transferred to the new system by a transfer program. The entire process is designed to be fail-safe. In the case that the Db2 should not be available, the change data is automatically buffered in a VSAM file.

In addition to the real-time replication, tcVISION is also used as an intelligent replacement for all of the customer's file transfer activities, as tcVISION supports constant checking of correctly transmitted data.

Meanwhile, the customer has converted almost all applications to the new system and all data changes to the new system are updated via tcVISION in the old system in order to meet all legal revision requirements. By using tcVISION, an orderly parallel operation was ensured, which ultimately enabled problem-free migration.