Web Distributed Computing Systems

The thesis presents the PhD study about a new approach in distributed computing based on the exploitation of web browsers as clents, using technologies and best practices of Javascript, AJAX and Flex. The described solution has two main advantages: it is client free, so no additional programs have to be installed to perform the computation, and it requires low CPU usage, so clientside computation is no invasive for users. The solution is developed with both AJAX and Adobe® Flex® technologies embedding a pseudoclient into a web page that hosts the computation in the form of a banner. While users browse the hosting web page, client side of the system query the server side part for a subproblem, called crunch, computes the solution(s) and sends back it to the server. All the process is always transparent for the users navigation experience and computer use in general. The thesis shows the feasibility of the system and the good performances that can be achieved, with details over tests and metrics that have been defined to measure the performance indexes. The new architecture has been tested through this performance metrics by implementing two examples of distributed computing, the cracking of the RSA cryptosystem through the factorization of the public key and the Pearson's correlation index between smples in genetic data sets. Results have shown good feasibility of this approach both in a closed environment and also in an Internet environment, in a typical real situation. A mathematical model has been developed over this solution. The main goals of the model are to describe and classify different categories of problems on the basis of the feasibility and o find the limits in the dimensioning of the scheduling systems to have convenience in the use of this approach.