Design and implementation of a software environment for distributed data access

Our vision, in this thesis, is the one of a bio-medical grip as a partner of hospital's information systems, sharing computing resources as well as a platform for sharing information. Therefore, we aim at (i) providing transparent access to huge distributed medical data sets, (ii) querying these data by their content, and (iii), sharing computing resources within the grip. Assuming the existence of a grip infrastructure, we suggest a multi-layered architecture (Distributed Systems Engines – DSE). This architecture allows us to design High Performance Distributed Systems which are highly extensible, scalable and open. It ensures the connection between the grip, data storing systems, and medical platforms. The conceptual design of the architecture assumes a horizontal definition for each one of the layers, and is based on a multi-process structure. This structure enables the exchange of messages between processes by using the Message Passing Paradigm. These processes and messages allow one to define entities of a higher level of semantic significance, which we call Drivers and, which instead of single messages, deal with different kinds of transactions: queries, tasks and requests. Thus, we define different kinds of drivers for dealing with each kind of transaction, and in a higher level, we define services as an aggregation of drivers. The architectural framework of drivers and services eases the design of components of a Distributed System (DS), which we call engines, and also eases the extensibility and scalability of DS