A general description of the approach followed in the thesis is described in this FastAbstract, which was presented at the FTCS-28, June 23-25, 1998, Munich, Germany.
In short, we claim that the operating system kernel should offer services specifically designed to support the implementation of current fault-tolerance techniques. Based on this set of services, user-level libraries can be built to provide application designers with ready-to-use (i.e. transparent) fault-tolerant (FT) techniques which can be readily incorporated to common applications. The strength of this approach is that the very same services used to develop general FT techniques are ready to be directly used when developing applications which require tailored FT techniques.
As it is described in the FastAbstract, "The most challenging aspect of this work has been to design services which let user-level processes combine the advantages provided by tailored checkpoint tools, with those offered by kernel-level services, mainly incremental and copy-on-write checkpointing. We have called this new services Incremental Messages (IMs), since they support selective and incremental state saving, updating and restoration through a message passing interface." IMs are described in this paper, which has been presented at the FTCS-29, June 15-18, 1999, Madison, Wisconsin, USA.
We are currently working in completing the implementation of the micro-kernel interface proposed in my thesis and in adding to VSTa (the micro-kernel we've used to test IMs) inter-node IM transfer capabilities. We are also continuing with the development of fault-tolerant applications and, finally, we are considering porting our work to a more established operating system in order to facilitate the deployment of Incremental Messages.