183 research outputs found

    Interfacing Ada to Operating Systems

    Get PDF

    An Execution Model for Fine-Grained Parallelism in Ada

    Get PDF
    20th International Conference on Reliable Software Technologies - Ada-Europe 2015 (Ada-Europe 2015), 25 to 29, Jun, 2015. Madrid, Spain. Best Paper Award.This paper extends the authors earlier proposal for providing Ada with support for fine-grained parallelism with an execution model based on the concept of abstract executors, detailing the progress guarantees that these executors must provide and how these can be assured even in the presence of potentially blocking operations. The paper also describes how this execution model can be applied to real-time systems

    Macrophage and Galleria mellonella infection models reflect the virulence of naturally occurring isolates of B. pseudomallei, B. thailandensis and B. oklahomensis

    Get PDF
    addresses: Biosciences, College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, UK.notes: PMCID: PMC3025829types: Journal Article; Research Support, Non-U.S. Gov't© 2011 Wand et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Burkholderia pseudomallei is the causative agent of melioidosis, a tropical disease of humans with a variable and often fatal outcome. In murine models of infection, different strains exhibit varying degrees of virulence. In contrast, two related species, B. thailandensis and B. oklahomensis, are highly attenuated in mice. Our aim was to determine whether virulence in mice is reflected in macrophage or wax moth larvae (Galleria mellonella) infection models

    Constraints on the Use of Executors in Real-time Systems

    Get PDF
    18th International Real-Time Ada Workshop (IRTAW 2016). 11 to 13, Apr, 2016. Benicàssim, Spain.Previous work proposed work to include parallelism in Ada to improve the use of multicore processors. This work proposed a model of Tasklets to carry the expressions of parallelism, and introduced the notion of executors to map the execution of Tasklets on hardware. In developing the model, a number of choices arise that effect how well the model will accommodate real-time systems. These choices become constraints which are examined and reasonable choices proposed for adoption in Ada.info:eu-repo/semantics/publishedVersio

    The type IV pilin, PilA, is required for full virulence of Francisella tularensis subspecies tularensis

    Get PDF
    Published onlineJournal ArticleThis is the final version of the article. Available from BioMed Central via the DOI in this record.BACKGROUND: All four Francisella tularensis subspecies possess gene clusters with potential to express type IV pili (Tfp). These clusters include putative pilin genes, as well as pilB, pilC and pilQ, required for secretion and assembly of Tfp. A hallmark of Tfp is the ability to retract the pilus upon surface contact, a property mediated by the ATPase PilT. Interestingly, out of the two major human pathogenic subspecies only the highly virulent type A strains have a functional pilT gene. RESULTS: In a previous study, we were able to show that one pilin gene, pilA, was essential for virulence of a type B strain in a mouse infection model. In this work we have examined the role of several Tfp genes in the virulence of the pathogenic type A strain SCHU S4. pilA, pilC, pilQ, and pilT were mutated by in-frame deletion mutagenesis. Interestingly, when mice were infected with a mixture of each mutant strain and the wild-type strain, the pilA, pilC and pilQ mutants were out-competed, while the pilT mutant was equally competitive as the wild-type. CONCLUSIONS: This suggests that expression and surface localisation of PilA contribute to virulence in the highly virulent type A strain, while PilT was dispensable for virulence in the mouse infection model

    Integrating Object-Oriented Programming and Protected Objects in Ada 95

    Get PDF
    Integrating concurrent and object-oriented programming as been an active research topic since the late 1980s. There is now a plethora of methods for achieving this integration. The majority of approaches have taken a sequential object-oriented language and made it concurrent. A few approaches have taken a concurrent language and made it object-oriented. The most important of this latter case is the Ada 95 language which is an extension to the object-based concurrent programming language Ada 83. Arguably, Ada 95 does not fully integrate its models of concurrency and object-oriented programming. For example. neither tasks nor protected objects are extensible. This paper discusses ways in which protected objects can be made more extensible
    corecore