93 research outputs found
Evolution of the Windows Kernel Architecture - Win7 and Beyond
No full text
The core architecture of the Windows kernel differs significantly from UNIX,
though many of the functions are necessarily similar. This talk will cover the
Windows kernel architecture, focusing on areas of difference from UNIX. Then
some specific recent kernel changes will be described: integrity levels, removalof the hottest kernel locks, and the move towards user-mode scheduling to
support the ConcRT task-based concurrency run-time. Finally, the talk will lookat some of the OS challenges ahead due to the silicon power-wall and the
resulting heterogeneous multi-core/many-core systems that will dominate the PC
landscape within a few years.
About the speaker
Dave Probert is a kernel architect within the Windows Core Operating Systems
Division at Microsoft where he is currently working on the next generations of
Windows. He is also the architect for the Windows Academic Program, developing
both the WRK package and ProjectOZ. Previously he managed kernel development for Windows, starting with the Windows 2000 release. Dave Probert joined Microsoft
in 1996, after earning his Ph.D. in Electrical & Computer Engineering at UC
Santa Barbara developing the SPACE project with Prof. John Bruno. His prior
industry experience includes serving as Vice President of Software Engineering
at Culler Scientific Systems, consulting for various companies on UNIX kernel
internals, and working as a systems architect at Burroughs corporation designinghardware and writing microcode for the B1900. During Spring Quarter 2009 Dave
Probert taught the undergraduate operating systems course at University of
Washington's Bothell campus using Windows.
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Defamation, A Camouflage of Psychic Interests: The Beginning of a Behavioral Analysis
No full textDoes the law of defamation need to be reformed? The author thinks so. Professor Probert rejects the doctrine of libel per se and questions the courts\u27 understanding and use of the term reputation. It is his belief that plaintiffs on an individual basis should have increased benefit of the knowledge accumulated by the various social sciences in proving the harm done by the alleged defamation, with more liberalization in the requirements of pleading and proof than is now generally countenanced by the courts
Environmentally induced transgenerational changes in seed longevity: Maternal and genetic influence
No full textBackground and Aims: Seed longevity, a fundamental plant trait for ex situ conservation and persistence in the soil of many species, varies across populations and generations that experience different climates. This study investigates the extent to which differences in seed longevity are due to genetic differences and/or modified by adaptive responses to environmental changes. Methods: Seeds of two wild populations of Silene vulgaris from alpine (wA) and lowland (wL) locations and seeds originating from their cultivation in a lowland common garden for two generations (cA1, cL1, cA2 and cL2) were exposed to controlled ageing at 45 °C, 60 % relative humidity and regularly sampled for germination and relative mRNA quantification (SvHSP17.4 and SvNRPD12). Key Results: The parental plant growth environment affected the longevity of seeds with high plasticity. Seeds of wL were significantly longer lived than those of wA. However, when alpine plants were grown in the common garden, longevity doubled for the first generation of seeds produced (cA1). Conversely, longevity was similar in all lowland seed lots and did not increase in the second generation of seeds produced from alpine plants grown in the common garden (cA2). Analysis of parental effects on mRNA seed provisioning indicated that the accumulation of gene transcripts involved in tolerance to heat stress was highest in wL, cL1 and cL2, followed by cA1, cA2 and wA. Conclusions: Seed longevity has a genetic basis, but may show strong adaptive responses, which are associated with differential accumulation of mRNA via parental effects. Adaptive adjustments of seed longevity due to transgenerational plasticity may play a fundamental role in the survival and persistence of the species in the face of future environmental challenges. The results suggest that regeneration location may have important implications for the conservation of alpine plants held in seed banks. © 2014 The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: [email protected]
State and Law
No full textThis is the author accepted manuscript. The final version is available in print format only from Bloombsbury
Theoretical and experimental evaluations of the convective and conductive heat transfers in a domestic hot-water store
No full textThe design of a water based thermal store for use in a domestic
central heating system has been investigated theoretically,
experimentally and numerically. The transient operation of the
store during both the space heating and domestic hot-water
modes of operation have been investigated separately.
Heat transfer correlations in terms of Nusselt and Rayleigh
numbers have been developed in order to predict the natural
convection heat transfer coefficient for the outside surface of
the horizontal axis finned tube heat exchanger coil located
within the store. These heat-transfer correlations can predict
the value of the heat transfer coefficient with an accuracy of
better than 5% and are in good agreement with existing heat
transfer correlations developed for the same geometry of finned
tubes and modes of heat transfer. The effect of the water flow
rate in the heat exchanger coil on the internal heat transfer
coefficient is also investigated. This flow rate should be
above 4 litre/minute to achieve a high rate of heat-transfer
from the wall of the heat exchanger to the water in the pipe.
A detailed investigation of the use of horizontal and vertical
baffles to increase the effectiveness of heat delivery in the
domestic hot water mode has been carried out. Some improvements
can be achieved by the use of a horizontal flat plate located
in the middle of the store. This plate, when correctly sized
enhances stratification and hence improves the effectiveness of
heat recovery. Vertical plate arrangements and a rectangular
duct situated around the upper heat exchanger coil were found
to be ineffective. However, due to an increased velocity of the
water around the heat exchanger, the external heat transfer
coefficient of the heat exchanger was increased by 12%.
The comparison of experimental observations with computer
simulations of the development of the thermocline in the store
during the space heating mode of operation showed the presence
of a jet in the bottom region of the store at the return inlet.
The jet induces a significant amount of mixing in the store
which reduces the effectiveness of heat recovery. Correlations
in terms of Richardson number and effectiveness of heat
delivery have been developed to characterize the effect of this
jet. An inlet arrangement designed to achieve a Richardson
number exceeding 3 significantly reduces the mixing created by
the jet and can increase the amount of heat delivered in the
space heating mode by approximately 5%
TNF and its receptors in the CNS: The essential, the desirable and the deleterious effects
No full textAbstractTumor necrosis factor (TNF) is the prototypic pro-inflammatory cytokine. It is central to host defense and inflammatory responses but under certain circumstances also triggers cell death and tissue degeneration. Its pleiotropic effects often lead to opposing outcomes during the development of immune-mediated diseases, particularly those affecting the central nervous system (CNS). The reported contradictions may result from lack of precision in discussing TNF. TNF signaling comprises at minimum a two-ligand (soluble and transmembrane TNF) and two-receptor (TNFR1 and TNFR2) system, with ligands and receptors both differentially expressed and regulated on different cell types. The “functional multiplicity” this engenders is the focus of much research, but there is still no general consensus on functional outcomes of TNF signaling in general, let alone in the CNS. In this review, evidence showing the effects of TNF in the CNS under physiological and pathophysiological conditions is placed in the context of major advances in understanding of the cellular and molecular mechanisms that govern TNF function in general. Thus the roles of TNF signaling in the CNS shift from the conventional dichotomy of beneficial and deleterious, that mainly explain effects under pathological conditions, to incorporate a growing number of “essential” and “desirable” roles for TNF and its main cellular source in the CNS, microglia, under physiological conditions including regulation of neuronal activity and maintenance of myelin. An improved holistic view of TNF function in the CNS might better reconcile the expansive experimental data with stark clinical evidence that reduced functioning of TNF and its dominant pro-inflammatory receptor, TNFR1, are risk factors for the development of multiple sclerosis. It will also facilitate the safe translation of basic research findings from animal models to humans and propel the development of more selective anti-TNF therapies aimed at selectively inhibiting deleterious effects of this cytokine while maintaining its essential and desirable ones, in the periphery and the CNS
Efficient Cross-domain Mechanisms for Building Kernel-less Operating Systems
No full textWe describe a set of efficient cross-domain mechanisms that allow operating systems to be implemented as cooperating applications, eliminating the need for a monolithic kernel. Our implementation, called SPACE[1, 2], can achieve higher-performance than kernel-based systems by allowing applications to build customized system services and tailor system interfaces for performance. On the SPARC architecture we have measured minimal application-to-application system service calls that are 5 times faster than Solaris getpid(), and customized thread creation that is 50 times faster than minimal Solaris threads. SPACE unifies exception handling and cross-domain calls into a single mechanism that allows applications to efficiently interface to the underlying hardware. Conventional memory-management hardware is used to provide multiple protection domains within each address space. Cross-domain calls are implemented by portals, which map an exception in one domain to a handler in another. Portals..
Building Fundamentally Extensible Application-Specific Operating Systems in SPACE
No full textWe refine and extend previous work [1] towards a new approach to implementing operating systems. This approach, called SPACE, uses processors, address spaces, and a generalized exception mechanism as the basic abstractions rather than processes, virtual memory, and interprocess communication. The result is that the facilities provided by the hardware architecture are exposed, and can be directly used by applications to achieve higher performance and more diverse functionality than is possible with conventional operating system abstractions. In SPACE the conventional abstractions can coexist with new application-specific abstractions, due to the fundamental extensibility of the SPACE primitives. Applications can implement their own versions of system services to satisfy critical functional and performance requirements while still benefiting from standard system services. We then give examples of implementing mechanisms in SPACE. 1 Introduction Historically operating systems were develo..
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