We propose a high-level approach to program distributed applications; it is based on the annotation future by which the programmer specifies which expressions may be evaluated remotely in parallel. We present the CEKDS-Machine, an abstract machine with a distributed memory, able to evaluate Scheme-like future-based programs. In this paper, we focus on the issue of task migration and prove that task migration is transparent to the user, i.e. task migration does not change the observable behaviour of programs