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Full-Text Articles in Physical Sciences and Mathematics
Expanding The Potential For Disk-Directed I/O, David Kotz
Expanding The Potential For Disk-Directed I/O, David Kotz
Dartmouth Scholarship
As parallel computers are increasingly used to run scientific applications with large data sets, and as processor speeds continue to increase, it becomes more important to provide fast, effective parallel file systems for data storage and for temporary files. In an earlier work we demonstrated that a technique we call disk-directed I/O has the potential to provide consistent high performance for large, collective, structured I/O requests. In this paper we expand on this potential by demonstrating the ability of a disk-directed I/O system to read irregular subsets of data from a file, and to filter and distribute incoming data according …
Exploring The Use Of I/O Nodes For Computation In A Mimd Multiprocessor, David Kotz, Ting Cai
Exploring The Use Of I/O Nodes For Computation In A Mimd Multiprocessor, David Kotz, Ting Cai
Dartmouth Scholarship
As parallel systems move into the production scientific-computing world, the emphasis will be on cost-effective solutions that provide high throughput for a mix of applications. Cost-effective solutions demand that a system make effective use of all of its resources. Many MIMD multiprocessors today, however, distinguish between “compute” and “I/O” nodes, the latter having attached disks and being dedicated to running the file-system server. This static division of responsibilities simplifies system management but does not necessarily lead to the best performance in workloads that need a different balance of computation and I/O. \par Of course, computational processes sharing a node with …
Multiprocessor File System Interfaces, David Kotz
Multiprocessor File System Interfaces, David Kotz
Dartmouth Scholarship
Increasingly, file systems for multiprocessors are designed with parallel access to multiple disks, to keep I/O from becoming a serious bottleneck for parallel applications. Although file system software can transparently provide high-performance access to parallel disks, a new file system interface is needed to facilitate parallel access to a file from a parallel application. We describe the difficulties faced when using the conventional (Unix-like) interface in parallel applications, and then outline ways to extend the conventional interface to provide convenient access to the file for parallel programs, while retaining the traditional interface for programs that have no need for explicitly …
Prefetching And Caching Techniques In File Systems For Mimd Multiprocessors, David F. Kotz
Prefetching And Caching Techniques In File Systems For Mimd Multiprocessors, David F. Kotz
Dartmouth Scholarship
The increasing speed of the most powerful computers, especially multiprocessors, makes it difficult to provide sufficient I/O bandwidth to keep them running at full speed for the largest problems. Trends show that the difference in the speed of disk hardware and the speed of processors is increasing, with I/O severely limiting the performance of otherwise fast machines. This widening access-time gap is known as the “I/O bottleneck crisis.” One solution to the crisis, suggested by many researchers, is to use many disks in parallel to increase the overall bandwidth. \par This dissertation studies some of the file system issues needed …
Prefetching In File Systems For Mimd Multiprocessors, Carla Schlatter Ellis, David Kotz
Prefetching In File Systems For Mimd Multiprocessors, Carla Schlatter Ellis, David Kotz
Dartmouth Scholarship
The problem of providing file I/O to parallel programs has been largely neglected in the development of multiprocessor systems. There are two essential elements of any file system design intended for a highly parallel environment: parallel I/O and effective caching schemes. This paper concentrates on the second aspect of file system design and specifically, on the question of whether prefetching blocks of the file into the block cache can effectively reduce overall execution time of a parallel computation, even under favorable assumptions. \par Experiments have been conducted with an interleaved file system testbed on the Butterfly Plus multiprocessor. Results of …