166,692 research outputs found

    VXA: A Virtual Architecture for Durable Compressed Archives

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    Data compression algorithms change frequently, and obsolete decoders do not always run on new hardware and operating systems, threatening the long-term usability of content archived using those algorithms. Re-encoding content into new formats is cumbersome, and highly undesirable when lossy compression is involved. Processor architectures, in contrast, have remained comparatively stable over recent decades. VXA, an archival storage system designed around this observation, archives executable decoders along with the encoded content it stores. VXA decoders run in a specialized virtual machine that implements an OS-independent execution environment based on the standard x86 architecture. The VXA virtual machine strictly limits access to host system services, making decoders safe to run even if an archive contains malicious code. VXA's adoption of a "native" processor architecture instead of type-safe language technology allows reuse of existing "hand-optimized" decoders in C and assembly language, and permits decoders access to performance-enhancing architecture features such as vector processing instructions. The performance cost of VXA's virtualization is typically less than 15% compared with the same decoders running natively. The storage cost of archived decoders, typically 30-130KB each, can be amortized across many archived files sharing the same compression method.Comment: 14 pages, 7 figures, 2 table

    Returns on Resilience: The Business Case

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    Real estate projects designed to withstand the effects of climate change can provide substantial returns on investment and an array of other benefits, according to this new report. Case studies from 10 leading resilience projects are highlighted, ranging from a Boston hospital built to withstand coastal storms to a residential community in San Antonio built to withstand the effects of intense heat and drought. Other communities with highlighted case studies include Queens, N.Y.; Miami, FL; Grand Cayman, Cayman Islands; Nashville, TN; Tucson, AZ and Lancaster, CA.The study found an array of benefits from the climate-smart designs in addition to their strength against climate unpredictability. They include:Better energy efficiency. For example, multilayered impact-resistant windows save energy and reduce utility bills.Greater marketing, sales and leasing success driven by buyers' desires for well-built structures that will withstand harsh conditions and keep their value longer.Better financing options and lower insurance rates based on the reduced risk from resilient and hardened structures
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