Watchdog, a WMS for the automated and distributed analysis of large-scale experimental data. The software is implemented in Java and is thus platform-independent. Main feature include + straightforward processing of replicate data + support for distributed computer systems + remote storage support + customizable error detection + manual intervention into workflow execution + GUI for workflow construction using pre-defined modules + a helper script for creating new module definitions + no restriction to specific programming languages + provides a flexible plugin system for extending without modifying the original sources