Virtualization with Limited Hardware Support

<p>In recent years, as mobile devices started to become an essential part of everyday computing, virtualization on mobile devices has begun to emerge as a solution for supporting multiple profiles on the same device. However, virtualization on mobile and embedded systems, and to a greater extent, on systems with limited hardware support for virtualization, often face different hardware environment than x86 platforms.</p><p>First of all, these platforms were usually equipped with CPUs that did not have hardware virtualization support. We propose a transparent and portable CPU virtualization solution for all types of CPUs that have hardware breakpoint functionality. We use a combination of the hardware breakpoint support and guest kernel control flow graph analysis to trap and emulate sensitive instructions.</p><p>Second, the traditional way of implementing record and replay which is an important feature of virtualization, cannot be implemented the same way on CPUs without hardware branch counters. We propose a record and replay implementation without using hardware branch counters on paravirtualized guests. We inspect guest virtual machine internal states to carefully rearrange recorded instructions during replay to achieve the same end result without having to literally repeat the same stream of instructions.</p><p>Third, these platforms are often equipped with storage systems with distinct I/O characteristics. SD card, for example, is a prevalent storage media on smartphones. We discuss the mismatch of I/O characteristics between SD card write speed characteristics and guest virtual machine workload characteristics using VMware Mobile Virtualization Platform as an example. We then propose a solution to bridge the gap and achieve efficient guest I/O when storing guest virtual disk images on SD cards.</p><p>This dissertation shows that it is possible to efficiently virtualize and provide advanced virtualization functionality to a range of systems without relying on x86 and PC specific virtualization technologies.</p>Dissertatio

A manifesto for future generation cloud computing: research directions for the next decade

The Cloud computing paradigm has revolutionised the computer science horizon during the past decade and has enabled the emergence of computing as the fifth utility. It has captured significant attention of academia, industries, and government bodies. Now, it has emerged as the backbone of modern economy by offering subscription-based services anytime, anywhere following a pay-as-you-go model. This has instigated (1) shorter establishment times for start-ups, (2) creation of scalable global enterprise applications, (3) better cost-to-value associativity for scientific and high performance computing applications, and (4) different invocation/execution models for pervasive and ubiquitous applications. The recent technological developments and paradigms such as serverless computing, software-defined networking, Internet of Things, and processing at network edge are creating new opportunities for Cloud computing. However, they are also posing several new challenges and creating the need for new approaches and research strategies, as well as the re-evaluation of the models that were developed to address issues such as scalability, elasticity, reliability, security, sustainability, and application models. The proposed manifesto addresses them by identifying the major open challenges in Cloud computing, emerging trends, and impact areas. It then offers research directions for the next decade, thus helping in the realisation of Future Generation Cloud Computing

Intermediador de serviços na Nuvem

Mestrado em Engenharia de Computadores e TelemáticaDe acordo com história dos sistemas informáticos, os engenheiros têm vindo a remodelar infraestruturas para melhorar a eficiência das organizações, visando o acesso partilhado a recursos computacionais. O advento da computação em núvem desencadeou um novo paradigma, proporcionando melhorias no alojamento e entrega de serviços através da Internet. Quando comparado com abordagens tradicionais, este apresenta vantajens por disponibilizar acesso ubíquo, escalável e sob demanda, a determinados conjuntos de recursos computacionais partilhados. Ao longo dos últimos anos, observou-se a entrada de novos operadores que providenciam serviços na núvem, a preços competitivos e diferentes acordos de nível de serviço (“Service Level Agreements”). Com a adoção crescente e sem precedentes da computação em núvem, os fornecedores da área estão se a focar na criação e na disponibilização de novos serviços, com valor acrescentado para os seus clientes. A competitividade do mercado e a existência de inúmeras opções de serviços e de modelos de negócio gerou entropia. Por terem sido criadas diferentes terminologias para conceitos com o mesmo significado e o facto de existir incompatibilidade de Interfaces de Programação Aplicacional (“Application Programming Interface”), deu-se uma restrição de fornecedores de serviços específicos na núvem a utilizadores. A fragmentação na faturação e na cobrança ocorreu quando os serviços na núvem passaram a ser contratualizados com diferentes fornecedores. Posto isto, seria uma mais valia existir uma entidade, que harmonizasse a relação entre os clientes e os múltiplos fornecedores de serviços na núvem, por meio de recomendação e auxílio na intermediação. Esta dissertação propõe e implementa um Intermediador de Serviços na Núvem focado no auxílio e motivação de programadores para recorrerem às suas aplicações na núvem. Descrevendo as aplicações de modo facilitado, um algoritmo inteligente recomendará várias ofertas de serviços na núvem cumprindo com os requisitos aplicacionais. Desta forma, é prestado aos utilizadores formas de submissão, gestão, monitorização e migração das suas aplicações numa núvem de núvens. A interação decorre a partir de uma única interface de programação que orquestrará todo um processo juntamente com outros gestores de serviços na núvem. Os utilizadores podem ainda interagir com o Intermediador de Serviços na Núvem a partir de um portal Web, uma interface de linha de comandos e bibliotecas cliente.Throughout the history of computer systems, experts have been reshaping IT infrastructure for improving the efficiency of organizations by enabling shared access to computational resources. The advent of cloud computing has sparked a new paradigm providing better hosting and service delivery over the Internet. It offers advantages over traditional solutions by providing ubiquitous, scalable and on-demand access to shared pools of computational resources. Over the course of these last years, we have seen new market players offering cloud services at competitive prices and different Service Level Agreements. With the unprecedented increasing adoption of cloud computing, cloud providers are on the look out for the creation and offering of new and valueadded services towards their customers. Market competitiveness, numerous service options and business models led to gradual entropy. Mismatching cloud terminology got introduced and incompatible APIs locked-in users to specific cloud service providers. Billing and charging become fragmented when consuming cloud services from multiple vendors. An entity recommending cloud providers and acting as an intermediary between the cloud consumer and providers would harmonize this interaction. This dissertation proposes and implements a Cloud Service Broker focusing on assisting and encouraging developers for running their applications on the cloud. Developers can easily describe their applications, where an intelligent algorithm will be able to recommend cloud offerings that better suit application requirements. In this way, users are aided in deploying, managing, monitoring and migrating their applications in a cloud of clouds. A single API is required for orchestrating the whole process in tandem with truly decoupled cloud managers. Users can also interact with the Cloud Service Broker through a Web portal, a command-line interface, and client libraries

Autonomous storage management for low-end computing environments

To make storage management transparent to users, enterprises rely on expensive storage infrastructure, such as high end storage appliances, tape robots, and offsite storage facilities, maintained by full-time professional system administrators. From the user's perspective access to data is seamless regardless of location, backup requires no periodic, manual action by the user, and help is available to recover from storage problems. The equipment and administrators protect users from the loss of data due to failures, such as device crashes, user errors, or virii, as well as being inconvenienced by the unavailability of critical files. Home users and small businesses must manage increasing amounts of important data distributed among an increasing number of storage devices. At the same time, expert system administration and specialized backup hardware are rarely available in these environments, due to their high cost. Users must make do with error-prone, manual, and time-consuming ad hoc solutions, such as periodically copying data to an external hard drive. Non-technical users are likely to make mistakes, which could result in the loss of a critical piece of data, such as a tax return, customer database, or an irreplaceable digital photograph. In this thesis, we show how to provide transparent storage management for home and small business users We introduce two new systems: The first, PodBase, transparently ensures availability and durability for mobile, personal devices that are mostly disconnected. The second, SLStore, provides enterprise-level data safety (e.g. protection from user error, software faults, or virus infection) without requiring expert administration or expensive hardware. Experimental results show that both systems are feasible, perform well, require minimal user attention, and do not depend on expert administration during disaster-free operation. PodBase relieves home users of many of the burdens of managing data on their personal devices. In the home environment, users typically have a large number of personal devices, many of them mobile devices, each of which contain storage, and which connect to each other intermittently. Each of these devices contain data that must be made durable, and available on other storage devices. Ensuring durability and availability is difficult and tiresome for non-expert users, as they must keep track of what data is stored on which devices. PodBase transparently ensures the durability of data despite the loss or failure of a subset of devices; at the same time, PodBase aims to make data available on all the devices appropriate for a given data type. PodBase takes advantage of storage resources and network bandwidth between devices that typically goes unused. The system uses an adaptive replication algorithm, which makes replication transparent to the user, even when complex replication strategies are necessary. Results from a prototype deployment in a small community of users show that PodBase can ensure the durability and availability of data stored on personal devices under a wide range of conditions with minimal user attention. Our second system, SLStore, brings enterprise-level data protection to home office and small business computing. It ensures that data can be recovered despite incidents like accidental data deletion, data corruption resulting from software errors or security breaches, or even catastrophic storage failure. However, unlike enterprise solutions, SLStore does riot require professional system administrators, expensive backup hard- ware, or routine, manual actions on the part of the user. The system relies on storage leases, which ensure that data cannot be overwritten for a pre-determined period, and an adaptive storage management layer which automatically adapts the level of backup to the storage available. We show that this system is both practical, reliable and easy to manage, even in the presence of hardware and software faults

Development of virtual network computing (VNC) environment for networking and enhancing user experience

Virtual Network Computing (VNC) is a thin client developed by Real VNC Ltd, Formerly of Olivetti Research Ltd/AT&T labs Cambridge and can be used as a collaborative environment, therefore it has been chosen as the basis of this research study. The purpose of this thesis is to investigate and develop a VNC based environment over the network and to improve the users’ Quality of Experience (QoE) of using VNC between networked groups by the incorporation of videoconferencing with VNC and enhancing QoE in Mobile environments where the network status is far from ideal and is prone to disconnection. This thesis investigates the operation of VNC in different environments and scenarios such as wireless environments by investigating user and device mobility and ways to sustain their seamless connection when in motion. As part of the study I also researched all groups that implement VNC like universities, research groups and laboratories and virtual laboratories. In addition to that I identified the successful features and security measures in VNC in order to create a secure environment. This was achieved by pinpointing the points of strength and weakness in VNC as opposed to popular thin clients and remote control applications and analysing VNC according to conforming to several security measures. Furthermore, it is reasonable to say that the success of any scheme that attempts to deliver desirable levels of Quality of Service (QoS) of an effective application for the future Internet must be based, not only on the progress of technology, but on usersʹ requirements. For instance, a collaborative environment has not yet reached the desired expectation of its users since it is not capable of handling any unexpected events which can result from a sudden disconnection of a nomadic user engaged in an ongoing collaborative session; this is consequently associated with breaking the social dynamics of the group collaborating in the session. Therefore, I have concluded that knowing the social dynamics of application’s users as a group and their requirements and expectations of a successful experience can lead an application designer to exploit technology to autonomously support the initiating and maintaining of social interaction. Moreover, I was able to successfully develop a VNC based environment for networked groups that facilitates the administration of different remote VNC sessions. In addition to a prototype that uses videoconferencing in parallel to VNC to provide a better user’s QoE of VNC. The last part of the thesis was concerned with designing a framework to improve and assess QoE of all users in a collaborative environment where it can be especially applied in the presence of nomadic clients with their much frequent disconnections. I have designed a conceptual algorithm called Improved Collaborative Quality of Experience (IC‐QoE), an algorithm that aims to eliminate frustration and improve QoE of users in a collaborative session in the case of disconnections and examined its use and benefits in real world scenarios such as research teams and implemented a prototype to present the concepts of this algorithm. Finally, I have designed a framework to suggest ways to evaluate this algorithm

Enhancing reliability with Latin Square redundancy on desktop grids.

Computational grids are some of the largest computer systems in existence today. Unfortunately they are also, in many cases, the least reliable. This research examines the use of redundancy with permutation as a method of improving reliability in computational grid applications. Three primary avenues are explored - development of a new redundancy model, the Replication and Permutation Paradigm (RPP) for computational grids, development of grid simulation software for testing RPP against other redundancy methods and, finally, running a program on a live grid using RPP. An important part of RPP involves distributing data and tasks across the grid in Latin Square fashion. Two theorems and subsequent proofs regarding Latin Squares are developed. The theorems describe the changing position of symbols between the rows of a standard Latin Square. When a symbol is missing because a column is removed the theorems provide a basis for determining the next row and column where the missing symbol can be found. Interesting in their own right, the theorems have implications for redundancy. In terms of the redundancy model, the theorems allow one to state the maximum makespan in the face of missing computational hosts when using Latin Square redundancy. The simulator software was developed and used to compare different data and task distribution schemes on a simulated grid. The software clearly showed the advantage of running RPP, which resulted in faster completion times in the face of computational host failures. The Latin Square method also fails gracefully in that jobs complete with massive node failure while increasing makespan. Finally an Inductive Logic Program (ILP) for pharmacophore search was executed, using a Latin Square redundancy methodology, on a Condor grid in the Dahlem Lab at the University of Louisville Speed School of Engineering. All jobs completed, even in the face of large numbers of randomly generated computational host failures

High-Performance Modelling and Simulation for Big Data Applications

This open access book was prepared as a Final Publication of the COST Action IC1406 “High-Performance Modelling and Simulation for Big Data Applications (cHiPSet)“ project. Long considered important pillars of the scientific method, Modelling and Simulation have evolved from traditional discrete numerical methods to complex data-intensive continuous analytical optimisations. Resolution, scale, and accuracy have become essential to predict and analyse natural and complex systems in science and engineering. When their level of abstraction raises to have a better discernment of the domain at hand, their representation gets increasingly demanding for computational and data resources. On the other hand, High Performance Computing typically entails the effective use of parallel and distributed processing units coupled with efficient storage, communication and visualisation systems to underpin complex data-intensive applications in distinct scientific and technical domains. It is then arguably required to have a seamless interaction of High Performance Computing with Modelling and Simulation in order to store, compute, analyse, and visualise large data sets in science and engineering. Funded by the European Commission, cHiPSet has provided a dynamic trans-European forum for their members and distinguished guests to openly discuss novel perspectives and topics of interests for these two communities. This cHiPSet compendium presents a set of selected case studies related to healthcare, biological data, computational advertising, multimedia, finance, bioinformatics, and telecommunications

Internet of Things From Hype to Reality

The Internet of Things (IoT) has gained significant mindshare, let alone attention, in academia and the industry especially over the past few years. The reasons behind this interest are the potential capabilities that IoT promises to offer. On the personal level, it paints a picture of a future world where all the things in our ambient environment are connected to the Internet and seamlessly communicate with each other to operate intelligently. The ultimate goal is to enable objects around us to efficiently sense our surroundings, inexpensively communicate, and ultimately create a better environment for us: one where everyday objects act based on what we need and like without explicit instructions