The following contribution describes a tool supported approach to creating a universal software repository. A universal repository is based on a data model which accomodates heterogeneous systems written in both procedural and object-oriented languages as well as database and interface description languages. In it the various semantic models - procedural, object-oriented, hierarchical and relational, map-based and web-based - are integrated into a single common architectural model. As a result, it is possible to depict all systems with UML diagrams, including the legacy systems. The common model is object-based and componentoriented. The advantage of this repository is the possibility of modelling a mixed system environment, an important prerequisite to Enterprise Application Integration.