This article presents the design and building of DSL-Lab, a platform to experiment on distributed computing over broadband domestic Internet. Experimental platforms such as PlanetLab and Grid'5000 are promising methodological approaches to study distributed systems. However, both platforms focus on high-end service and network deployments only available on a restricted part of the Internet, leaving aside the possibility for researchers to experiment in conditions close to what is usually available with domestic connection to the Internet. DSL-Lab is a complementary approach to PlanetLab and Grid'5000 to experiment with distributed computing in an environment closer to how Internet appears, when applications are run on end-user PCs. DSL-Lab is a set of 40 low-power and low-noise nodes, which are hosted by participants, using the participants' xDSL or cable access to the Internet. The objective is to provide a validation and experimentation platform for new protocols, services, simulators and emulators for these systems. In this paper, we report on the software design (security, resources allocation, power management) as well as on the first experiments achieved.

Cloud Computing has taken commercial computing by storm. However, adoption of cloud computing platforms and services by the scientific community is in its infancy as the performance and monetary cost-benefits for scientific applications are not perfectly clear. This is especially true for desktop grids (aka volunteer computing) applications. We compare and contrast the performance and monetary cost-benefits of clouds for desktop grid applications, ranging in computational size and storage. We address the following questions: (i) What are the performance tradeoffs in using one platform over the other? (ii) What are the specific resource requirements and monetary costs of creating and deploying applications on each platform? (iii) In light of those monetary and performance cost-benefits, how do these platforms compare? (iv) Can cloud computing platforms be used in combination with desktop grids to improve cost-effectiveness even further? We examine those questions using performance measurements and monetary expenses of real desktop grids and the Amazon elastic compute cloud.

Desktop grid (DG) systems use the idle computing power of many volunteered desktop PC's on the Internet to support large-scale computation and storage. For over a decade, DG systems have been the largest and the most powerful distributed computing systems, offering a plethora of computing power at a fraction of the cost of supercomputers. The volunteer desktops participating in DG projects are volatile and heterogeneous, but there is little detailed information about their volatility and heterogeneity. Yet this characterization is essential for the simulation and modelling of such systems. We are conducting a project whose goal is to obtain a detailed picture of the DG landscape. To this end, we are deploying resource sensors on the volunteer desktops to measure the availability of CPU, disk space, memory, and network bandwidth. An initial version of the project has been deployed and currently has about 1,800 participating hosts. The resulting resource measurement data and characterization will be useful for a broad range of research areas, including distributed and peer-to-peer computing, and fault tolerance