Ulf Troppens and Rainer Erkens are employed at IBM TotalStorage Interoperability Center in Mainz, a testing, development and demonstration laboratory for storage products and storage networks. Both authors work at the interface between technology and customers. Their duties include the testing of new products and the validation of concepts on the basis of customer environments set up in the laboratory. They present the latest hardware and software products in the field of storage networks to customers and discuss the set up test environment with them.