  AliEn (ALICE Environment) is a GRID-like system for large scale job
submission and distributed data management developed and used in the context of
ALICE, the CERN LHC heavy-ion experiment. With the aim of exploiting upcoming
Grid resources to run AliEn-managed jobs and store the produced data, the
problem of AliEn-EDG interoperability was addressed and an in-terface was
designed. One or more EDG (European Data Grid) User Interface machines run the
AliEn software suite (Cluster Monitor, Storage Element and Computing Element),
and act as interface nodes between the systems. An EDG Resource Broker is seen
by the AliEn server as a single Computing Element, while the EDG storage is
seen by AliEn as a single, large Storage Element; files produced in EDG sites
are registered in both the EDG Replica Catalogue and in the AliEn Data
Catalogue, thus ensuring accessibility from both worlds. In fact, both
registrations are required: the AliEn one is used for the data management, the
EDG one to guarantee the integrity and access to EDG produced data. A prototype
interface has been successfully deployed using the ALICE AliEn Server and the
EDG and DataTAG Testbeds.
