7 research outputs found

    Snowflake: Spanning administrative domains

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    Many distributed systems provide a ``single-system image\u27\u27 to their users, so the user has the illusion that they are using a single system when in fact they are using many distributed resources. It is a powerful abstraction that helps users to manage the complexity of using distributed resources. The goal of the Snowflake project is to discover how single-system images can be made to span administrative domains. Our current prototype organizes resources in namespaces and distributes them using Java Remote Method Invocation. Challenging issues include how much flexibility should be built into the namespace interface, and how transparent the network and persistent storage should be. We outline future work on making Snowflake administrator-friendly

    Advancing Operating Systems via Aspect-Oriented Programming

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    Operating system kernels are among the most complex pieces of software in existence to- day. Maintaining the kernel code and developing new functionality is increasingly compli- cated, since the amount of required features has risen significantly, leading to side ef fects that can be introduced inadvertedly by changing a piece of code that belongs to a completely dif ferent context. Software developers try to modularize their code base into separate functional units. Some of the functionality or “concerns” required in a kernel, however, does not fit into the given modularization structure; this code may then be spread over the code base and its implementation tangled with code implementing dif ferent concerns. These so-called “crosscutting concerns” are especially dif ficult to handle since a change in a crosscutting concern implies that all relevant locations spread throughout the code base have to be modified. Aspect-Oriented Software Development (AOSD) is an approach to handle crosscutting concerns by factoring them out into separate modules. The “advice” code contained in these modules is woven into the original code base according to a pointcut description, a set of interaction points (joinpoints) with the code base. To be used in operating systems, AOSD requires tool support for the prevalent procedu- ral programming style as well as support for weaving aspects. Many interactions in kernel code are dynamic, so in order to implement non-static behavior and improve performance, a dynamic weaver that deploys and undeploys aspects at system runtime is required. This thesis presents an extension of the “C” programming language to support AOSD. Based on this, two dynamic weaving toolkits – TOSKANA and TOSKANA-VM – are presented to permit dynamic aspect weaving in the monolithic NetBSD kernel as well as in a virtual- machine and microkernel-based Linux kernel running on top of L4. Based on TOSKANA, applications for this dynamic aspect technology are discussed and evaluated. The thesis closes with a view on an aspect-oriented kernel structure that maintains coherency and handles crosscutting concerns using dynamic aspects while enhancing de- velopment methods through the use of domain-specific programming languages

    Building high-performance web-caching servers

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    Naming and sharing resources across administrative boundaries

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    I tackle the problem of naming and sharing resources across administrative boundaries. Conventional systems manifest the hierarchy of typical administrative structure in the structure of their own mechanism. While natural for communication that follows hierarchical patterns, such systems interfere with naming and sharing that cross administrative boundaries, and therefore cause headaches for both users and administrators. I propose to organize resource naming and security, not around administrative domains, but around the sharing patterns of users. The dissertation is organized into four main parts. First, I discuss the challenges and tradeoffs involved in naming resources and consider a variety of existing approaches to naming. Second, I consider the architectural requirements for user-centric sharing. I evaluate existing systems with respect to these requirements. Third, to support the sharing architecture, I develop a formal logic of sharing that captures the notion of restricted delegation. Restricted delegation ensures that users can use the same mechanisms to share resources consistently, regardless of the origin of the resource, or with whom the user wishes to share the resource next. A formal semantics gives unambiguous meaning to the logic. I apply the formalism to the Simple Public Key Infrastructure and discuss how the formalism either supports or discourages potential extensions to such a system. Finally, I use the formalism to drive a user-centric sharing implementation for distributed systems. I show how this implementation enables end-to-end authorization, a feature that makes heterogeneous distributed systems more secure and easier to audit. Conventionally, gateway services that bridge administrative domains, add abstraction, or translate protocols typically impede the flow of authorization information from client to server. In contrast, end-to-end authorization enables us to build gateway services that preserve authorization information, hence we reduce the size of the trusted computing base and enable more effective auditing. I demonstrate my implementation and show how it enables end-to-end authorization across various boundaries. I measure my implementation and argue that its performance tracks that of similar authorization mechanisms without end-to-end structure. I conclude that my user-centric philosophy of naming and sharing benefits both users and administrators

    Теоретико-методические основы комбинированного обучения системному программированию будущих специалистов программной инженерии

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    Спецвипуск містить монографію А. М. Стрюка, у якій теоретично обґрунтовано та розроблено модель використання системи управління навчанням для організації комбінованого навчання системного програмування бакалаврів програмної інженерії; уточнено поняття комбінованого навчання; удосконалено організаційну модель комбінованого навчання у ВНЗ, що передбачає використання системи управління навчанням; дістала подальший розвиток модель освітньо-наукового інформаційного порталу ВНЗ. Практична частина дослідження присвячена опису розробки програмного засобу навчального призначення «Система управління комбінованим навчанням «Агапа» та методики його використання у комбінованому навчанні системного програмування бакалаврів програмної інженерії. Для науковців, викладачів та студентів вищих навчальних закладів, аспірантів та всіх тих, кого цікавлять сучасні теорія та методика використання ІКТ в освіті.The A. M. Striuk monograph gives a broad outline of theoretical grounds as well as develops the model of using LMS in the blended learning of System Programming for Software Engineering BA students. It also specifies the notion of blended learning, improves the LMS-based model of blended learning at a higher educational establishment, thus contributing to the further elaborating the concept of educational and scientific informational university portal. The practical significance of the research primarily lies in developing the LMS «Agapa» and methods for its implementing in blended learning of System Programming for Software Engineering BA students. Experimental implementation of the technique in question has clearly demonstrated that organising an educational process of teaching System Programming according to the model of blended learning based on usage of the «Agapa» system enhances the level of educational attainment. For researchers, teachers and university students, graduate students and all those interested in contemporary using of ICT in education theory and methods.Спецвыпуск содержит монографию А. Н. Стрюка, в которой теоретически обоснована и разработана модель использования системы управления обучением для организации комбинированного обучения системного программирования бакалавров программной инженерии; уточнено понятие комбинированного обучения; усовершенствована организационная модель комбинированного обучения в вузе, предполагающая использование системы управления обучением; получила дальнейшее развитие модель научно-образовательного информационного портала вуза. Практическая часть исследования посвящена описанию разработки программного средства учебного назначения «Система управления комбинированным обучением «Агапа» и методики его использования в комбинированном обучении системного программирования бакалавров программной инженерии. Для научных работников, преподавателей и студентов высших учебных заведений, аспирантов и всех тех, кого интересуют современные теория и методика использования ИКТ в образовании

    On Improving The Performance And Resource Utilization of Consolidated Virtual Machines: Measurement, Modeling, Analysis, and Prediction

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    This dissertation addresses the performance related issues of consolidated \emph{Virtual Machines} (VMs). \emph{Virtualization} is an important technology for the \emph{Cloud} and data centers. Essential features of a data center like the fault tolerance, high-availability, and \emph{pay-as-you-go} model of services are implemented with the help of VMs. Cloud had become one of the significant innovations over the past decade. Research has been going on the deployment of newer and diverse set of applications like the \emph{High-Performance Computing} (HPC), and parallel applications on the Cloud. The primary method to increase the server resource utilization is VM consolidation, running as many VMs as possible on a server is the key to improving the resource utilization. On the other hand, consolidating too many VMs on a server can degrade the performance of all VMs. Therefore, it is necessary to measure, analyze and find ways to predict the performance variation of consolidated VMs. This dissertation investigates the causes of performance variation of consolidated VMs; the relationship between the resource contention and consolidation performance, and ways to predict the performance variation. Experiments have been conducted with real virtualized servers without using any simulation. All the results presented here are real system data. In this dissertation, a methodology is introduced to do the experiments with a large number of tasks and VMs; it is called the \emph{Incremental Consolidation Benchmarking Method} (ICBM). The experiments have been done with different types of resource-intensive tasks, parallel workflow, and VMs. Furthermore, to experiment with a large number of VMs and collect the data; a scheduling framework is also designed and implemented. Experimental results are presented to demonstrate the efficiency of the ICBM and framework
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