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Betriebssysteme, Kommunikationssysteme und Verteilte Systeme (SYS)

https://dl.gi.de/handle/20.500.12116/6251
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Auflistung Betriebssysteme, Kommunikationssysteme und Verteilte Systeme (SYS) nach Erscheinungsdatum

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  • Textdokument
    In Microservices We Trust — Do Microservices Solve Resilience Challenges?
    (Tagungsband des FB-SYS Herbsttreffens 2019, 2019) Hilbrich, Marcus
    Resilience is an open challenge. In this paper we look into microservices – a concept that argues to be resilient. We look into the definition of microservices and argue whether the definition provides the promised advantages regarding to resilience.
  • Textdokument
    Towards a Robust, Self-Organizing IoT Platform for Secure and Dependable Service Execution
    (Tagungsband des FB-SYS Herbsttreffens 2019, 2019) Eichhammer, Philipp; Berger, Christian; Reiser, Hans P.; Domaschka, Jörg; Hauck, Franz J.; Habiger, Gerhard; Griesinger, Frank; Pietron, Jakob
    In the IoT, resilience capabilities increasingly gain traction for applications, as IoT systems tend to play a bigger role for both the proper functioning of our society and the survivability of companies. However, hardening IoT service execution against a variety of possible faults and attacks becomes increasingly difficult as the complexity, size and heterogeneity of IoT infrastructures tend to grow further and further. Moreover, many existing solutions only regard either specific faults or security issues instead of following a unifying approach. In this position paper, we present our research project called SORRIR, which essentially is an approach to develop a self-organizing IoT platform for dependable and secure service execution. One of our main ambitions is to support developers by separating application development (app logic) from resilience properties, so that developers can configure a desired resilience degree without proper knowledge of underlying technical, implementation-level details of employed resilience mechanisms. Further, we consider security requirements and properties as an integral component of our platform.
  • Textdokument
    Systems Support For Efficient State-Machine Replication
    (Tagungsband des FB-SYS Herbsttreffens 2019, 2019) Habiger, Gerhard; Hauck, Franz J.
    State-Machine Replication (SMR) is a well known approach for the deployment of highly fault-tolerant services. Recent research has focused on efficiency improvements, performance optimisation and novel approaches to underlying concepts of SMR, such as consensus with trusted components, dynamic weights for quorums, or parallelisation of application code. To increase adoption of SMR as a basic fault-tolerance technique, we see the need to improve the current state of the art of SMR even further, and provide four specific ways in which our research contributes to this goal. In particular, we present two approaches which make the development and deployment of SMR services both easier and more efficient, and talk about two further areas of improvement concerning internal mechanisms of common SMR architectures. The goal of this paper is to provide our current understanding of important issues of current SMR systems as well as to outline possible future solutions to them.
  • Textdokument
    Efficient Checkpointing in Byzantine Fault-Tolerant Systems
    (Tagungsband des FB-SYS Herbsttreffens 2019, 2019) Eischer, Michael; Distler, Tobias
    Distributed Byzantine fault-tolerant systems require frequent checkpoints of the application state to perform periodic garbage collection and enable faulty replicas to recover efficiently. State-of-the-art checkpointing approaches for replicated systems either cause significant service disruption when the application state is large, or they are unable to produce checkpoints that are verifiable across replicas. To address these problems we developed and evaluated deterministic fuzzy checkpointing, a technique to create consistent and verifiable checkpoints in parallel with request execution.
  • Textdokument
    Group-based Memory Management in Fyr
    (Tagungsband des FG-BS Herbsttreffens 2020, 2020) Weis, Torben; Zdankin, Peter; Carl, Oskar; Waltereit, Marian
    Albeit being introduced decades ago, C and C++ are still the most commonly used programming languages for operating systems. These languages have no reliable mechanisms to deal with memory safety issues, such as use-after-free or data race conditions, that are a leading cause for security bugs in operating systems and other critical software. Tools such as Valgrind have been developed to identify errors, but the errors must occur during the analysis, as they are not found otherwise. Several modern programming languages such as Rust, Go and Swift have emerged aiming to solve some of the issues by providing memory safety guarantees at compile or run time. However, these languages introduce new limitations, especially concerning software development for performance-critical or resource-constrained systems. In this paper, we introduce a new approach to automatic memory management that manages the lifetime of object groups instead of individual objects. We show that group-based memory management can remove some of the restrictions of modern programming languages while satisfying important memory safety constraints. Furthermore, we show how group-based memory management is implemented in our new systems programming language Fyr.
  • Textdokument
    Improving Linux-Kernel Tests for LockDoc with Feedback-driven Fuzzing
    (Tagungsband des FG-BS Herbsttreffens 2020, 2020) Lochmann, Alexander; Thunig, Robin; Schirmeier, Horst
    LockDoc is an approach to extract locking rules for kernel data structures from a dynamic execution trace recorded while the system is under a benchmark load. These locking rules can e.g. be used to locate synchronization bugs. For high rule precision and thorough bug finding, the approach heavily depends on the choice of benchmarks: They must trigger the execution of as much code as possible in the kernel subsystem relevant for the targeted data structures. However, existing test suites such as those provided by the Linux Test Project (LTP) only achieve – in the case of LTP – about 35 percent basic-block coverage for the VFS subsystem, which is the relevant subsystem when extracting locking rules for filesystem-related data structures. In this article, we discuss how to complement the LTP suites to improve the code coverage for our LockDoc scenario. We repurpose syzkaller – a coverage-guided fuzzer with the goal to validate the robustness of kernel APIs – to 1) not aim for kernel crashes, and to 2) maximize code coverage for a specific kernel subsystem. Thereby, we generate new benchmark programs that can be run in addition to the LTP, and increase VFS basic-block coverage by 26.1 percent.
  • Textdokument
    Persistent Streams: The Internet With Ephemeral Storage
    (Tagungsband des FG-BS Herbsttreffens 2021, 2021) Carl, Oskar; Zdankin, Peter; Schaffeld, Matthias; Matkovic, Viktor; Yu, Yang; Elbers, Timo; Weis, Torben
    Communication in the internet today is transient by default. Because of this, whenever an application needs to store data even for a moment, its provider needs to develop an application-specific solution, which is often done using client-server models. This is costly at scale, and generally requires users to concede control over the data they generate to allow application providers to generate revenue from the collected data to finance the operation of these servers. This also leads to a lock-in effect, which is prohibitive for new applications entering a market. To solve these issues, we propose persistent streams, an application-agnostic communication protocol that includes ephemeral and persistent storage and is able to handle both discrete as well as continuous (streaming) data. Including storage into the communication path removes the need for application servers completely. Even though the protocol relies on (cloud) servers as transmission and storage proxies, we expect the emergence of new storage technologies like non-volatile main memory to alleviate some issues this introduces. We also show the general applicability of this solution using different kinds of applications as examples. Overall, persistent streams have the potential to greatly reduce the burdens on application providers while also enabling users to exercise increased control over their data.
  • Textdokument
    A Study on the Portability of IoT Operating Systems
    (Tagungsband des FG-BS Frühjahrstreffens 2021, 2021) Martins Gomes, Renata; Baunach, Marcel
    The IoT is set to permeate our lives as a new and global super infrastructure, where billions of devices with an unprecedented variety of hardware architectures will interact. To enable IoT applications and services to run everywhere without major adaptation, operating systems (OS) provide standardized interfaces to the heterogeneous hardware. As a consequence, an operating system for IoT devices must be available for a huge number of target platforms, from low-end to high-end devices, and it must guarantee different levels of dependability (e.g., safety, security, real-time, maintainability) that each application will require. Some of these hardware architectures do already exist, others will emerge over time and introduce new or improved features that must be supported or exploited by the OS. In order to succeed, an OS must thus be portable, not only concerning its functionality, but also its verified dependability. This paper tries to answer the question of how portable existing IoT OSs are, analyzing five popular OSs on their design, development, and testing processes, as well as the quality of available ports. We close with a suggestion on how to improve portability for future OS designs.
  • Textdokument
    Developing Bare-Metal GPGPU Drivers From Scratch: What prevents scientists from developing own GPGPU drivers?
    (Tagungsband des FG-BS Frühjahrstreffens 2021, 2021) Lütke Dreimann, Marcel; Kessener, Daniel
    Most of modern computers use Graphic Processing Units (GPUs) as an additional source of computing power. However, using GPUs in bare-metal research operating systems comes with some challenges. Existing drivers for Linux or Windows are complex and cannot be used for without much effort. Documentation of modern GPUs is often missing or incomplete and drivers are incomprehensive or closed source. This paper tries to explain what prevents scientists from creating their own GPU drivers. Additionally, it gives an overview about GPGPU driver development for GPUs from different manufactur- ers and shows some challenges. Nevertheless, we have ambitiously started an undertaking to develop our own driver from scratch. To some extend this was successful, but with many problems on the way.
  • Textdokument
    First Things First: A Discussion of Modelling Approaches for Disruptive Memory Technologies
    (Tagungsband des FG-BS Herbsttreffens 2021, 2021) Müller, Michael; Kessener, Daniel; Spinczyk, Olaf
    Disruptive memory technologies (DMT) are dramatically changing the architecture of modern computer systems and affect important design decisions throughout the whole software stack. For their success it is crucial that developers of system software and applications find ways to fully exploit the potential of the novel hardware. Having appropriate DMT hardware models is the key to successful optimization in the world of system software and application development. Therefore, this paper introduces four relevant new DMTs and corresponding performance analyzes as well as modelling approaches. We conclude with the insight that there is a lack of system-wide models that are practically applicable by system software designers for proper optimization and, thus, an important domain for future research.