In this paper, we present Novasky, a real-world Video-on-Demand (VoD) system capable of delivering cinematic-quality video streams to end users. The foundation of the Novasky design is a peer-to-peer (P2P) storage cloud, storing and refreshing media streams in a decentralized fashion using local storage spaces of end users. We present our design objectives in Novasky, and how these objectives are achieved using a collection of unique mechanisms, with respect to caching strategies, coding mechanisms, and the maintenance of the supply-demand relationship when it comes to media availability in the P2P storage cloud. The production Novasky system has been implemented with over 100,000 lines of code. It has been deployed in the Tsinghua University campus network, operational since September 2009, attracting 10,000 users to date, and providing over 1,000 cinematic-quality video streams with bit rates of 1 - 2 Mbps. Based on real-world traces collected over 6 months, we show that Novasky can achieve rapid startups within 4 - 9 seconds, and extremely short seek latencies within 3 seconds. Our empirical experiences with Novasky may bring valuable insights to future designs of production-quality P2P storage cloud systems.

Wireless monitor system are widely used in recent years, but there are a few problems to solve, such as scalability and adaptability, and monitor system based on MANET has more difficulties because of multi-hop links and mutable channels. A new MANET monitor system based on Service-oriented architecture (MMS-SOA) is proposed to make the system easier to manage dynamically such as dynamic deployment, on-line update, dynamic entering and exit and supply better streaming video QoS which are more important in some severe environment (battlefields, earthquakes, etc.). What's more, it also provides a better scalability. This paper illustrates the design of MMS-SOA's architecture, and how it works .

Isolated Distributed Stream Servers (IDSS) is the main form of video-on-demand (VOD) service architecture in industrial community nowadays. Contrast to the previous work on load sharing in distributed VOD system which all follows the idea of having high-speed inner network among service nodes, in this paper, we firstly focus on load sharing algorithm under IDSS architecture and introduce global stream distribution optimization, future user arrival rate estimation and more disk storage redundancy rate to make the effect of load sharing more satisfactory. Moreover the influence of video redundancy rate and some other parameters in our algorithm is detected through simulation. Preliminary experiment results suggest that our algorithm outperforms existing load sharing algorithms under IDSS architecture and sometimes even works better than existing ones with inner network.

Abstract The Grid is a new type of resource sharing infrastructure. Due to software and hardware limitations, the service that a certain Grid can offer is finite, and so is the number of users it can accommodate. If the number of users is too small, much of the planned resources would be wasted. On the other hand, excessive loading due to too many users could substantially reduce the benefit enjoyed by each user and also the efficiency of the Grid service. Therefore, there are two main problems for Grid design. (1) How many users should the Grid serve so that each user can receive the maximum benefit? (2) To a certain group of users, how much resources should be invested so that the construction and maintenance of the Grid become viable? Based on the economic theory of clubs, this paper gives a quantitative analysis of the quasi‐optimal number of users and amount of each resource by regarding Grid services and resources as club goods. Based on our assumptions on the system model, we deduce two preliminary results and verify them by experiments using GridFTP. These two results allow the users to run randomized algorithms to achieve better system performance. Copyright © 2006 John Wiley & Sons, Ltd.

Grid is focused by the researchers theses years. In grid, resource registry meta-service assumes the responsibility for the register managing and indexing of resources in grid. It's very important for the running of grid. In this paper, we present a resource description system and provide its reference by XML schema first. Then, we design the distributed resource registry meta-service and implement it based on Java language. At last, the test and tryout indicate that it can provide high-performance and robust resource registering and indexing services.

In the light of the increasingly serious I/O bottleneck problem, the paper puts forward a method named RAID-M (RAID Matrix) to build high performance mass storage from cheap PC components based on the idea of multi-channel I/O and parallel access. Theoretical analyses prove that different RAID-M configurations vary their performance, space utilization and reliability, meeting various application goals. Experiments show that both the sequential read performance and sequential write performance of a RAID-M prototype machine have broken through the limitation of 32 bit/33 MHz PCI bus. Copyright by Science in China Press 2005.

Virtual Interface Architecture (VIA) established a communication model with low latency and high bandwidth, and defined the standard of user-level high-performance communication specification in cluster systems. This paper analyzes the current development, principle and implementations of VIA, and presents user-level high-performance communication software, MyVIA, based on Myrinet, which is comfortable with VIA specification. The paper first describes the design principle and framework of MyVIA, then proposes new technologies of MyVIA including User TLB, continued host physical memory and varied NIC buffer, the pipelining communication based on resource and DMA chain, and physical descriptor ring. Experimental results of performance comparisons and analysis are presented; the one-way bandwidth of MyVIA for a 4 KB message is 250 MB/s, and the lowest one-way latency is 8.46 /spl mu/s, which shows that the performance of MyVIA surpassed that of other implementations of VIA.