A thorough system specification is insufficient to guarantee that a compute
r system will adequately perform its tasks during its entire fife cycle. Th
e early evaluation of system characteristics like dependability, correctnes
s and performance is necessary to assess the conformance of the system unde
r development to its targets. This paper presents the results achieved so f
ar to develop an integrated environment, where design tools based on the UM
L (Unified Modeling Language) are augmented with validation and analysis te
chniques that provide useful information in the early phases of system desi
gn. Automatic transformations are defined for the generation of models to c
apture system behavioral properties, dependability and performance.