Isaac D. Scherson

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A working single system image distributed operating system is presented. Dubbed Kerrighed, it provides a unified approach and support to both the MPI and the shared memory programming models. The system is operational in a 16-processor cluster at the Institut de Recherche en Informatique et Systemes Aleatoires in Rennes, France. In this paper, the system is(More)
The time complexity of ray tracing is a function of the data structures used for space division. Octree and hierarchical extents have been suggested as effective choices. In this paper, complexity parameters are suggested to characterize images and show that both octrees and hierarchies are appropriate choices if given most favorable images. Also, a unified(More)
Least Common Ancestor Networks (LCANs) are introduced and shown to be a class of networks that include fat-trees, baseline networks, SW-banyans and the router networks of the TRAC 1.1 and 2.0, and the CM-5. Some LCAN properties are stated and the permutation routing capabilities of an important subclass are analyzed. Simulation results for three permutation(More)
The performance evaluation of processor-memory commu-<lb>nications for multiprocessor systems using circuit switched interconnec-<lb>tion networks with a hold strategy is performed. In addition to the<lb>parameters that previous researchers used, we take into account message<lb>size and processor processing time which are shown in this paper to<lb>have a(More)
In this paper we propose a new class of scheduling policies, dubbed Concurrent Gang, that combines the advantages of gang scheduling for communication and synchronization intensive parallel jobs with the flexibility of a Unix scheduler for sequential and I/O intensive jobs. Besides that, scalability in Concurrent Gang is achieved through the use of a global(More)
Current MIMD computers support the execution of data parallel programs by providing a tree network to perform fast barrier synchronizations. However, there are two major limitations to using tree networks: The rst arises due to control nesting in programs, and the second arises when the MIMD computer needs to run several programs simultaneously. First, we(More)