Migrating operating system instances across distinct physical hosts is a useful tool for administrators of data centers and clusters: It allows a clean separation between hardware and software, and facilitates fault management, load balancing, and low-level system maintenance. By carrying out the majority of migration while OSes continue to run, we achieve impressive performance with minimal service downtimes; we demonstrate the migration of entire OS instances on a commodity cluster, recording service downtimes as low as 60ms. We show that that our performance is sufficient to make live migration a practical tool even for servers running interactive loads. In this paper we consider the design options for migrating OSes running services with liveness constraints, focusing on data center and cluster environments. We introduce and analyze the concept of writable working set, and present the design, implementation and evaluation of highperformance OS migration built on top of the Xen VMM. 1

Figure 1: Our system takes unstructured collections of photographs such as those from online image searches (a) and reconstructs 3D points and viewpoints (b) to enable novel ways of browsing the photos (c). We present a system for interactively browsing and exploring large unstructured collections

Recent empirical and case study evidence documents a strong association between the adoption of computers and increased use of college educated or non-production workers. With few exceptions, the conceptual link explaining how computer technology complements skilled labor or substitutes for unskilled labor is less well developed. This paper applies an understanding of what computers do – the execution of procedural or rules-based logic – to develop and test a simple model of how the widespread adoption of computers in the workplace might alter workplace skill demands. Two essential contentions of our framework are that computer capital (1) substitutes for a limited and well-defined set of human activities, those involving routine (repetitive) cognitive and manual tasks; and (2) complements a second set of activities, those involving non-routine problem solving and interactive tasks. Under the assumption that routine and non-routine tasks are imperfect substitutes, the task framework implies measurable changes in the task content of employment. We examine these changes using representative samples of workers from 1960 to 1998 where individual characteristics are augmented with Dictionary of Occupational Title variables describing their occupations ’ requirements for routine and non-routine cognitive and manual skills. We find that computerization is associated with declining relative industry

Contract No. 68-C7-0051

Virtual reality (VR) is typically defined in terms of technological hardware. This paper attempts to cast a new, variable-based definition of virtual reality that can be used to classify virtual reality in relation to other media. The defintion of virtual reality is based on concepts of "

This paper examines the structure of option valuation problems and develops a new technique for their solution. It also introduces several jump and diffusion processes which have nol been used in previous models. The technique is applied lo these processes to find explicit option valuation formulas, and solutions to some previously unsolved problems involving the pricing ofsecurities with payouts and potential bankruptcy. 1.

-late. Often there is no feasible method to recharge motes, so energy is a precious resource. Once deployed, a network must be reprogrammable although physically unreachable, and this reprogramming can be a significant energy cost. We present Maté, a tiny communication-centric virtual machine designed

Abstract Several common systems satisfy some but not all of the VR This paper describes the CAVE (CAVE Automatic Virtual Environment) virtual reality/scientific visualization system in detail and demonstrates that projection technology applied to virtual-reality goals achieves a system that matches

We describe an augmented reality conferencing system which uses the overlay of virtual images on the real world. Remote collaborators are represented on Virtual Monitors which can be freely positioned about a user in space. Users can collaboratively view and interact with virtual objects using a

information visualization, information physics. We describe the current status of Pad++, a zooming graphical interface that we are exploring as an alternative to tradhional window and icon-based approaches to interface design. We discuss the motivation for Pad++, describe the implementation