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Efficient virtualization of translation lookaside buffers (TLBs), a core component of modern hypervisors, is complicated by the concurrent, speculative walking of page tables in hardware. We give a formal model of an x64-like TLB, criteria for its correct virtualization, and outline the verification of a virtualization algorithm using shadow page tables.(More)
Efficient TLB virtualization is a core component of modern hypervisors. Verifying such code is challenging; the code races with TLB virtualization code in other processors, with other guest threads, and with the hardware TLBs, and implements an abstract TLB that races with other abstract TLBs and guest threads. We give a general methodology for verifying(More)
A fundamental problem in concurrent system design is to identify flexible programming disciplines under which weak memory models provide sequential consistency. For x86-TSO, a suitable reduction theorem for threads that communicate only through shared memory was given by Cohen and Schirmer [5]. However, this theorem cannot handle programs that edit their(More)
5,6,7,8-Tetrafluoro-3lambda4delta2,1,2,4-benzothiaselenadiazine (1) is prepared by the intramolecular nucleophilic cyclization of C6F5SeN=S=NSiMe3 (2) mediated by CsF. According to an X-ray diffraction analysis, the heterocycle of 1 is bent along the Se(1)...N4 line by 6.0(2) degrees in the crystal. Despite the obvious similarities between 1 and its(More)
The existence of the orbital interaction presented in the literature as being the cause for the stabilisation of the Z,Z configuration of Ph-S-N=S=N-S-Ph (1) and its derivatives in the crystal phase, has been investigated. The results of theoretical calculations at the DFT/B3LYP/6-311+G* level of theory suggest that such a stabilising interaction might not(More)
1. Introduction The role of design optimization in CAD is central. Classical theories of optimization (differential calculus, variational calculus, optimal control theory, mathematical programming) deal with the case when this domain design parameters is infinite. From this angle, the subject of discrete optimization, where the domain design parameters is(More)
Discrete-event and analytical simulation are two widely used approaches to simulating telecommunication networks. But the growth in size and complexity of modern networks increases the need for hybrid simulation models. Discrete-event simulation of very large networks can last days. On the other hand, assumptions and approximations of analytical models(More)
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