Search results for "Operating system"
showing 10 items of 134 documents
Biological and clinical significance of dysplastic hematopoiesis in patients with newly diagnosed multiple myeloma
2020
On behalf of the PETHEMA/GEM Cooperative Group.
Handling precedence constraints in scheduling problems by the sequence pair representation
2015
In this paper, we show that sequence pair (SP) representation, primarily applied to the rectangle packing problems appearing in the VLSI industry, can be a solution representation of precedence constrained scheduling. We present three interpretations of sequence pair, which differ in complexity of schedule evaluation and size of a corresponding solution space. For each interpretation we construct an incremental precedence constrained SP neighborhood evaluation algorithm, computing feasibility of each solution in the insert neighborhood in an amortized constant time per examined solution, and prove the connectivity property of the considered neighborhoods. To compare proposed interpretations…
Scheduling Multimodal Transportation Systems
2004
Abstract In this paper a Lagrangian based heuristic procedure for scheduling transportation networks is presented. The solution procedure schedules a single line at a time, possibly correcting the previous decisions at each step.
A recurrence-free variant of strassen’s algorithm on hypercube
1995
In this paper a non-recursive Strassen’s matrix multiplication algorithm is presented. This new algorithm is suitable to run on parallel environments. Two computational schemes have been worked out exploiting different parallel approaches on hypercube architecture. A comparative analysis is reported. The experiments have been carried out on an nCUBE-2 supercomputer, housed at CNUCE in Pisa, supporting the Express parallel operating system. © 1995, Taylor & Francis Group, LLC. All rights reserved.
Towards Dynamic Scripted pNFS Layouts
2012
Today's network file systems consist of a variety of complex subprotocols and backend storage classes. The data is typically spread over multiple data servers to achieve higher levels of performance and reliability. A metadata server is responsible for creating the mapping of a file to these data servers. It is hard to map application specific access patterns to storage system specific features, which can result in a degraded IO performance. We present an NFSv4.1/pNFS protocol extension that integrates the client's ability to provide hints and I/O advices to metadata servers. We define multiple storage classes and allow the client to choose which type of storage fits best for its desired ac…
ADA-FS—Advanced Data Placement via Ad hoc File Systems at Extreme Scales
2020
Today’s High-Performance Computing (HPC) environments increasingly have to manage relatively new access patterns (e.g., large numbers of metadata operations) which general-purpose parallel file systems (PFS) were not optimized for. Burst-buffer file systems aim to solve that challenge by spanning an ad hoc file system across node-local flash storage at compute nodes to relief the PFS from such access patterns. However, existing burst-buffer file systems still support many of the traditional file system features, which are often not required in HPC applications, at the cost of file system performance.
Simurgh
2021
The availability of non-volatile main memory (NVMM) has started a new era for storage systems and NVMM specific file systems can support extremely high data and metadata rates, which are required by many HPC and data-intensive applications. Scaling metadata performance within NVMM file systems is nevertheless often restricted by the Linux kernel storage stack, while simply moving metadata management to the user space can compromise security or flexibility. This paper introduces Simurgh, a hardware-assisted user space file system with decentralized metadata management that allows secure metadata updates from within user space. Simurgh guarantees consistency, durability, and ordering of updat…
ATL model checking in the cloud
2015
This paper gives an overview of our recent work on implementing a new interactive ATL model checker for verification of open systems. In verification based on model checking, we need to provide a model of the system and also write down the properties (ATL formulas) that we require the system to satisfy. Traditionally, the semantics of ATL is given in terms of concurrent game structures. In contrast to previous approaches, our tool permits an interactive design of the ATL models as state-transition graphs, and is based on client/server architecture. The server part, published as Web service in OpenShift cloud platform, embeds the core of the ATL model checker, and the client provides an intu…
Reengineering an Approach to Model-Driven Development of Business Apps
2015
Despite a perceived convergence in mobile application development, platforms such as Android and iOS remain largely incompatible. Supporting multiple platforms currently requires either separate native development (for each system) or utilization of a cross-platform development framework. While many such frameworks have been developed, only few are mature and even less are used widely, let alone commercially. Moreover, they typically are limited with regard to performance and to preserving a native look & feel. Worst of all, their usefulness for business apps is limited due to their low level of abstraction. In this paper, we take a closer look at an academic prototype that employs model-dr…
Multithreaded Translation of Ptolemy II Designs on Multicore Platforms
2008
Ptolemy II is an open source environment for system design and test based on component data flow. This paradigm tries to make parallel systems more deterministic and understandable. In this work we propose a technique to translate designs developed with Ptolemy II, into multithreaded Java implementations on multicore platforms. We have chosen Java mainly because Ptolemy II is implemented in Java and then we get direct code reuse. The counterpart is a certain amount of overhead that we expect to be less relevant as Java runtime environment will evolve. The main goals are to produce efficient parallel simulators and software devices with competitive performance level. We show by means of an e…