Delta compression, which consists of compactly encoding one le version as the result of changes to another, can improve eciency in the use of network and disk resources. Delta compression techniques are readily available and can result in compression factors of ve to ten on typical data. Managing delta-compressed storage, however, is a dicult task. I will present a system that attempts to isolate the complexity of delta-compressed storage management by separating the task of version labeling from performance issues. I will show how the system integrates delta-compressed transport with delta-compressed storage. Existing tools for managing delta-compressed storage suer from weak le system support. Lack of transaction support is responsible for inecient application behavior. The only atomic operation in the traditional le system forces unnecessary disk activity due to copying costs. I will demonstrate that transaction support can improve application performance and extensibility wit...

Figure 1: Streakline visualization of a 2 TB turbopump data set, with particles colored by pressure. Because the geometry is proprietary, the pump blades are not shown and some remaining geometry is decimated. This paper describes the methods used to produce an interactive visualization of a 2 TB computational fluid dynamics (CFD) data set using particle tracing (streaklines). We use the method introduced by Bruckschen et al. [3] that precomputes a large number of particles, stores them on disk using a space-filling curve ordering that minimizes seeks, then retrieves and displays the particles according to the user’s command. We describe how the particle computation can be performed using a PC cluster, how the algorithm can be adapted to work with a multi-block curvilinear mesh, how scalars can be extracted and used to color the particles, and how the out-ofcore visualization can be scaled to 293 billion particles while still achieving interactive performance on PC hardware. Compared to the earlier work, our data set size and total number of particles are an order of magnitude larger. We also describe a new compression technique that losslessly reduces the amount of particle storage by 41 % and speeds the particle retrieval by about 20%. CR Categories: I.3.8 [Computer Graphics]: Applications; E.4 [Coding and Information Theory]: Data compaction and

In this paper, we describe bundling, a technique for the transfer of files over a network. The goal of bundling is to group together files that tend to be needed in the same program execution and that are loaded close together. We describe an algorithm for dividing a collection of files into bundles based on profiles of file-loading behavior.

. This paper reports the design and implementation of ANU-Store, a transactional object store. The twin goals of flexibility and performance dominate the design of ANU-Store. The design includes: strong support for SMP concurrency; stand-alone, client-server and client-peer distribution configurations; configureable logging and recovery; and object management which can accommodate garbage collection and clustering mechanisms. The first implementation of ANU-Store incorporates a number of innovations. (1) A new recovery algorithm derived from ARIES that removes the need for log seqeuence numbers to be present on store pages. (2) A zero-copy memory-mapped buffer manager with controlled write-back behavior. (3) New data structures for highly concurrent locking and map querying. We present performance results comparing ANUStore with a stream-lined implemention of the SHORE object store. For both medium and small OO7 workloads ANU-Store outperforms SHORE across a wide range of ...

This paper reports the design and implementation of Platypus, a transactional object store. The twin goals of flexibility and performance dominate the design of Platypus. The design includes: support for SMP concurrency; standalone, client-server and client-peer distribution configurations; configurable logging and recovery; and object management which can accommodate garbage collection and clustering mechanisms. The first implementation of Platypus incorporates a number of innovations. (1) A new recovery algorithm derived from ARIES that removes the need for log sequence numbers to be present in store pages. (2) A zero-copy memory-mapped buffer manager with controlled write-back behavior. (3) A data structure for highly concurrent map querying. We present performance results comparing Platypus with SSM, the storage layer of the SHORE object store. For both medium and small OO7 workloads Platypus outperforms SHORE across a wide range of benchmark operations in both `hot' and `cold' settings. 1

Increasingly advances in file carving, memory analysis and network forensics requires the ability to identify the underlying type of a file given only a file fragment. Work to date on this problem has relied on identification of specific byte sequences in file headers and footers, and the use of statistical analysis and machine learning algorithms taken from the middle of the file. We argue that these approaches are fundamentally flawed because they fail to consider the inherent internal structure in widely used file types such as PDF, DOC, and ZIP. We support our argument with a bottom-up examination of some popular formats and an analysis of TK PDF files. Based on our analysis, we argue that specialized methods targeted to each specific file type will be necessary to make progress in this area. 1.

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Abstract—Smartphone is becoming a key element in providing greater user access to the mobile Internet. Many complex applications, which are used to be only on PCs, have been developed and run on smartphones. These applications extend the functionalities of smartphones and make them more convenient for users to be connected. However, they also greatly increase the power consumption of smartphones and many users are frustrated with the long delay of web browsing when using smartphones. In this paper, we have discovered that the key reason of the long delay and high power consumption in web browsing is not due to the bandwidth limitation most of time in 3G networks. The local computation limitation at the smartphone is the real bottleneck for opening most webpages. To address this issue, we propose an architecture, called Virtual-Machine based Proxy (VMP), to shift the computing from smartphones to the VMP. To illustrate the feasibility of deploying the proposed VMP system in 3G networks, we have built a prototype using Xen virtual machines and Android Phones with T-Mobile UMTS network. Experimental results show that compared to normal smartphone browser, our VMP approach reduces the delay by more than 80 % and reduces the power consumption during web browsing by more than 45%. I.