This book constitutes the thoroughly refereed joint post-workshop proceedings of three international events: the International Workshop on Highly Parallel Processing on a Chip, HPPC 2007, the UNICORE Summit 2007, and the Workshop on Virtualization/Xen in High-Performance Cluster and Grid Computing, VHPC 2007, held in Rennes, France, in August 2007 within the scope of Euro-Par 2007, the 13th International Conference on Parallel Computing.

The 8 papers of the HHPC 2007 workshop address all aspects of existing and emerging/envisaged multi-core processors with a significant amount of parallelism, especially to considerations on novel paradigms and models and the related architectural and linguistic support. The 8 papers presented at the UNICORE Summit 2007 show current developments and implementations of the UNICORE middleware system - a grid technology, providing a seamless, secure, and intuitive access to distributed Grid resources. UNICORE is a full-grown and well-tested Grid middleware system, which today is used in daily production worldwide. The 9 papers of the VHPC 2007 workshop present new models for implementing high-performance computing (HPC) architectures in both cluster and grid environments and cover areas including performance of virtual machine monitors (VMM), VMM architecture and implementation, cluster and grid VMM applications, management of VM-based computing resources, and hardware support for virtualization.