Travelling through wormholes

The evolution of distributed computing and applications has put new challenges on models, architectures and systems. To name just one, 'reconciling uncertainty with predictability' is required by today's simultaneous pressure on increasing the quality of service of applications, and on degrading the assurance given by the infrastructure.This challenge can be mapped onto more than one facet, such as time or security or others. In this paper we explore the time facet, reviewing past and present of distributed systems models, and making the case for the use of hybrid (vs. homogeneous) models, as a key to overcoming some of the difficulties faced when asynchronous models (uncertainty) meet timing specifications (predictability). The Wormholes paradigm is described as the first experiment with hybrid distributed systems models.