AST Manhattan D服务器系列

随着多媒体、互联网、数据软件应用的普及，对于初级用户或计算机老手来说，性能强劲、易于升级的服务器系统无疑是必备之选，AST以台式机的价格，为您提供具有完善网络功能的服务器机种Manhattan D。     

Benchmarking Engineering Workstations

As workstations become more popular, it is increasingly important to be able to measure and compare their relative performance. However, benchmarks are often either too specific to be of general interest or too general to be relevant to a specific application. We have constructed a collection of benchmarks?for a common kind of engineering workstation?that give a good approximation of processor, graphics, file access, and multitasking performance while being small and simple enough to easily transport. We have run the benchmarks on a number of workstations, including Sun-3, Apollo 560, VAXstation-II, and IRIS 2400, with overall results meeting our approximate expectations. Our approach allows us to quickly assess the performance of new workstations.     

支持复杂行为的单用户虚拟环境

通过对行为的真实感的深入分析,提出了一个基于行为的动态负载分配算法来提高具有复杂行为的单用户虚拟环境的可伸缩性。该算法具体实现于分布式虚拟环境软件开发平台ＨＹＶＲＰ中。测试结果表明,该算法能有效地调节系统负载,在提高用户实时交互能力的前提下,尽是保持了行为的真实感。     

论"单物理层的用户数据传输平面体系结构网络"--SUPANET

文中从未来“三网合一”的需求出发,分析了现有的三层和两层通信子网体系结构存在用户数据传输效率低、难以保障各类数据的服务质量的缺点,提出了从Intemet逐步向单物理层的用户数据传输平面体系结构网络(SUPANET)过渡。重点讨论了SUPANET保证服务质量的相关技术,对其核心技术——“物理帧时槽交换技术”也进行了简要的介绍。     

PCC:一个对单用户建模的个性化对话系统

对话系统是自然语言处理(NLP)领域中一个重要的下游任务,在近几年得到了越来越多的关注,并取得了很大的发展.然而尽管对话领域已经取得了许多优秀的成果,现有的对话模型在拓展个性化方面依然有很大的局限性.为了使对话模型更符合人类的对话方式,拥有更好的个性化建模能力,该文提出一种新的对单个用户建模的个性化模型PCC(a Pe...     

Broadcasting on Networks of Workstations

Broadcasting and multicasting are fundamental operations. In this work we develop algorithms for performing broadcast and multicast in clusters of workstations. In this model, sending a message to a machine in the same cluster takes 1 time unit, and sending a message to a machine in a different cluster takes C(≥1) time units. The clusters may have arbitrary sizes. Lowekamp and Beguelin proposed heuristics for this model, but their algorithms may produce broadcast times that are arbitrarily worse than optimal. We develop the first constant factor approximation algorithms for this model. Algorithm LCF (Largest Cluster First) for the basic model is simple, efficient and has a worst case approximation guarantee of 2. We then extend these models to more complex models where we remove the assumption that an unbounded amount of communication may happen using the global network. The algorithms for these models build on the LCF method developed for the basic problem. Finally, we develop broadcasting algorithms for the postal model where the sending node does not block for C time units when the message is in transit.     

工程工作站技术进展

本文简要地分析了工程工作站的特征,提出工程工作站是集运算、图形处理以及网络功能于一体的计算机系统。本文给出了工程工作站组成与性能指标分析,重点介绍工程工作站技术在运算部件、图形处理部件以及体系结构等方面的进展,最后总结了工程工作站成功的技术因素。     

PERQ and Advanced Raster Graphics Workstations

A National Network of Inexpensive, High-Powered, Single-User Computers with Good Interactive Capabilities Is Being Launched in the UK.     

Parallel Application Scheduling on Networks of Workstations

Parallel applications can be executed using the idle computing capacity of workstation clusters. However, it remains unclear how to schedule the processors among different applications most effectively. Processor scheduling algorithms that were successful for shared-memory machines have proven to be inadequate for distributed memory environments due to the high costs of remote memory accesses and redistributing data. We investigate how knowledge of system load and application characteristics can be used in scheduling decisions. We propose a new algorithm based on adaptive equipartitioning, which, by properly exploiting both the information types above, performs better than other nonpreemptive scheduling rules, and nearly as well as idealized versions of preemptive rules (with free preemption). We conclude that the new algorithm is suitable for use in scheduling parallel applications on networks of workstations.     

Workstations speed care delivery to critically ill

A busy intensive-care unit in the Veterans Affairs Medical Center in Palo Alto, Calif., has begun to put the power of workstation technology to good use in caring for the facility's sickest patients. Adam Seiver, M.D., chief of general surgery, told Computers in Healthcare that the system tracks patient information far more accurately than the manual methods used previously. Before the system, a patient's ICU records were filed away after each 48-hour period. Now a complete history of the patient's ICU stay is accessible at the beside through the duration of the episode.     

工作站网络系统进程迁移机制

进程迁移是工作站网络系统实现负载平衡、提高系统可用性功能的重要手段.该文提出了一种基于接收/发送方消息记录的进程迁移技术.它在消息传递库PVM(parallel virtual machine)之上实现,具有对用户程序透明、可移植性好、开销小和实现简单等特点.此技术已实际应用于作者自行研制的“并行程序运行回卷恢复与进程迁移系统—ChaRM(checkpointing-based rollback recovery and migration system)”中.     

Coordinating Parallel Processes on Networks of Workstations

The network of workstations (NOW) we consider for scheduling is heterogeneous and nondedicated, where computing power varies among the workstations and local and parallel jobs may interact with each other in execution. An effective NOW scheduling scheme needs sufficient information about system heterogeneity and job interactions. We use the measured power weight of each workstation to quantify the differences of computing capability in the system. Without a processing power usage agreement between parallel jobs and local user jobs in a workstation, job interactions are unpredictable, and performance of either type of jobs may not be guaranteed. Using the quantified and deterministic system information, we design a scheduling scheme calledself-coordinated local schedulingon a heterogeneous NOW. Based on a power usage agreement between local and parallel jobs, this scheme coordinates parallel processes independently in each workstation based on the coscheduling principle. We discuss its implementation on Unix System V Release 4 (SVR4). Our simulation results on a heterogeneous NOW show the effectiveness of the self-coordinated local scheduling scheme.     

A Bridge from Full-Function to Reduced-Function Workstations

This article describes a system that allows a reduced-function workstation, an Apple Macintosh, to perform as a low-end node in an Apollo Domain workstation network. Programs that run in the Apollo environment do not have to be modified to be accessed from the Macintosh; the appropriate system subroutines are intercepted and recast into a suitable form. Each Apollo workstation can support from two to three Macintosh PCs, making the average cost per console as little as $5000. A similar project is underway for the IBM PC family of computers.     

Alternatives to Coscheduling a Network of Workstations

Efficient scheduling of processes on processors of a Network of Workstations (NOW) is essential for good system performance. However, the design of such schedulers is challenging because of the complex interaction between several system and workload parameters. Coscheduling, though desirable, is impractical for such a loosely coupled environment. Two operations, waiting for a message and arrival of a message, can be used to take remedial actions that can guide the behavior of the system toward coscheduling using local information. We present a taxonomy of three possibilities for each of these two operations, leading to a design space of 3×3 scheduling mechanisms. This paper presents an extensive implementation and evaluation exercise in studying these mechanisms. Adhering to the philosophy that scheduling and communication are intertwined and should be studied in conjunction, a complete communication substrate for UltraSPARC workstations, connected by Myrinet and running Solaris 2.5.1, has been developed. This platform provides the entire Message Passing Interface (MPI) to readily run off-the-shelf MPI applications by employing protected low-latency user-level messaging. Several applications can concurrently use this interface. This platform has been used to design, implement, and uniformly evaluate nine scheduling strategies with a mixture of concurrent real applications with varying communication intensities. This includes five new schemes (Periodic Boost, Periodic Boost with Spin Block, Spin Yield, Periodic Boost with Spin Yield, Dynamic Coscheduling with Spin Yield) that are presented in this paper. In addition to our evaluations of the pros and cons of each mechanism in terms of throughput, response time, CPU utilization, and fairness, it is shown that Periodic Boost is a promising approach for scheduling processes on a NOW.