José María Pérez

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Data replication is a practical and effective method to achieve efficient and fault-tolerant data access in grids. Traditionally, data replication schemes maintain an entire replica in each site where a file is replicated, providing a read-only model. These solutions require huge storage resources to store the whole set of replicas and do not allow(More)
Every storage platform intended to fit the requirements of the multimedia systems must incorporate a disk scheduling mechanism and a cache architecture that can handle their special needs. On the other hand, the general trend is to make integrated storage platforms that meet the requirements of deterministic applications, multimedia systems, and traditional(More)
Parallelism in file systems is obtained by using several independent server nodes supporting one or more secondary storage devices. This approach increases the performance and scalability of the system, but a fault in one single node can stop the whole system. To avoid this problem, data must be stored using some kind of redundant technique, so any data(More)
One important piece of system software for clusters is the parallel file system. All current parallel file systems and parallel I/O libraries for clusters do not use standard servers, thus it is very difficult to use these systems in heterogeneous environments. However why use proprietary or special-purpose servers on the server end of a parallel file(More)
Functional requirements for information systems can be modeled through use cases. Furthermore, use case models have been successfully used in broader contexts than software engineering, as systems engineering. Even if small systems may be modeled as a set of use cases, when large systems requirements are modeled with a plain use case model several(More)
BACKGROUND We performed this observational prospective study to evaluate the results of the application of a diagnostic and therapeutic algorithm for complicated parapneumonic pleural effusion (CPPE) and pleural parapneumonic empyema (PPE). MATERIAL/METHODS From 2001 to 2007, 210 patients with CPPE and PPE were confirmed through thoracocentesis and(More)