FADI: a fault-tolerant environment for open distributed computing

FADI is a complete programming environment that serves the reliable execution of distributed application programs. FADI encompasses all aspects of modern fault-tolerant distributed computing. The built-in user-transparent error detection mechanism covers processor node crashes and hardware transient failures. The mechanism also integrates user-assisted error checks into the system failure model. The nucleus non-blocking checkpointing mechanism combined with a novel selective message logging technique delivers an efficient, low-overhead backup and recovery mechanism for distributed processes. FADI also provides means for remote automatic process allocation on the distributed system nodes

Effective interprocess communication (IPC) in a real-time transputer network

The thesis describes the design and implementation of an interprocess communication (IPC) mechanism within a real-time distributed operating system kernel (RT-DOS) which is designed for a transputer-based network. The requirements of real-time operating systems are examined and existing design and implementation strategies are described. Particular attention is paid to one of the object-oriented techniques although it is concluded that these techniques are not feasible for the chosen implementation platform. Studies of a number of existing operating systems are reported. The choices for various aspects of operating system design and their influence on the IPC mechanism to be used are elucidated. The actual design choices are related to the real-time requirements and the implementation that has been adopted is described. [Continues.

OpenSwarm: an event-driven embedded operating system for miniature robots

This paper presents OpenSwarm, a lightweight easy-to-use open-source operating system. To our knowledge, it is the first operating system designed for and deployed on miniature robots. OpenSwarm operates directly on a robot’s microcontroller. It has a memory footprint of 1 kB RAM and 12 kB ROM. OpenSwarm enables a robot to execute multiple processes simultaneously. It provides a hybrid kernel that natively supports preemptive and cooperative scheduling, making it suitable for both computationally intensive and swiftly responsive robotics tasks. OpenSwarm provides hardware abstractions to rapidly develop and test platformindependent code. We show how OpenSwarm can be used to solve a canonical problem in swarm robotics—clustering a collection of dispersed objects. We report experiments, conducted with five e-puck mobile robots, that show that an OpenSwarm implementation performs as good as a hardware-near implementation. The primary goal of OpenSwarm is to make robots with severely constrained hardware more accessible, which may help such systems to be deployed in real-world applications

Fast Lean Erasure-Coded Atomic Memory Object

In this work, we propose FLECKS, an algorithm which implements atomic memory objects in a multi-writer multi-reader (MWMR) setting in asynchronous networks and server failures. FLECKS substantially reduces storage and communication costs over its replication-based counterparts by employing erasure-codes. FLECKS outperforms the previously proposed algorithms in terms of the metrics that to deliver good performance such as storage cost per object, communication cost a high fault-tolerance of clients and servers, guaranteed liveness of operation, and a given number of communication rounds per operation, etc. We provide proofs for liveness and atomicity properties of FLECKS and derive worst-case latency bounds for the operations. We implemented and deployed FLECKS in cloud-based clusters and demonstrate that FLECKS has substantially lower storage and bandwidth costs, and significantly lower latency of operations than the replication-based mechanisms

Master of Science

thesisOperating system (OS) kernel extensions, particularly device drivers, are one of the primary sources of vulnerabilities in commodity OS kernels. Vulnerabilities in driver code are often exploited by attackers, leading to attacks like privilege escalation, denial-of-service, and arbitrary code execution. Today, kernel extensions are fully trusted and operate within the core kernel without any form of isolation. But history suggests that this trust is often misplaced, emphasizing a need for some isolation in the kernel. We develop a new framework for isolating device drivers in the Linux kernel. Our work builds on three fundamental principles: (1) strong isolation of the driver code; (2) reuse of existing driver while making no or minimal changes to the source; and (3) achieving same or better performance compared to the nonisolated driver. In comparison to existing driver isolation schemes like driver virtual machines and user-level device driver implementations, our work strives to avoid modifying existing code and implements an I/O path without incurring substantial performance overhead. We demonstrate our approach by isolating a unmodified driver for a null block device in the Linux kernel, achieving near-native throughput for block sizes ranging from 512B to 256KB and outperforming the nonisolated driver for block sizes of 1MB and higher

Terrier: an embedded operating system using advanced types for safety

Operating systems software is fundamental to modern computer systems: all other applications are dependent upon the correct and timely provision of basic system services. At the same time, advances in programming languages and type theory have lead to the creation of functional programming languages with type systems that are designed to combine theorem proving with practical systems programming. The Terrier operating system project focuses on low-level systems programming in the context of a multi-core, real-time, embedded system, while taking advantage of a dependently typed programming language named ATS to improve reliability. Terrier is a new point in the design space for an operating system, one that leans heavily on an associated programming language, ATS, to provide safety that has traditionally been in the scope of hardware protection and kernel privilege. Terrier tries to have far fewer abstractions between program and hardware. The purpose of Terrier is to put programs as much in contact with the real hardware, real memory, and real timing constraints as possible, while still retaining the ability to multiplex programs and provide for a reasonable level of safety through static analysis

POSH: Paris OpenSHMEM: A High-Performance OpenSHMEM Implementation for Shared Memory Systems

In this paper we present the design and implementation of POSH, an Open-Source implementation of the OpenSHMEM standard. We present a model for its communications, and prove some properties on the memory model defined in the OpenSHMEM specification. We present some performance measurements of the communication library featured by POSH and compare them with an existing one-sided communication library. POSH can be downloaded from \url{http://www.lipn.fr/~coti/POSH}. % 9 - 67Comment: This is an extended version (featuring the full proofs) of a paper accepted at ICCS'1

Interprocess communication in highly distributed systems

Issued as Final technical report, Project no. G-36-632Final technical report has title: Interprocess communication in highly distributed system

The AURORA Gigabit Testbed

AURORA is one of five U.S. networking testbeds charged with exploring applications of, and technologies necessary for, networks operating at gigabit per second or higher bandwidths. The emphasis of the AURORA testbed, distinct from the other four testbeds, BLANCA, CASA, NECTAR, and VISTANET, is research into the supporting technologies for gigabit networking. Like the other testbeds, AURORA itself is an experiment in collaboration, where government initiative (in the form of the Corporation for National Research Initiatives, which is funded by DARPA and the National Science Foundation) has spurred interaction among pre-existing centers of excellence in industry, academia, and government. AURORA has been charged with research into networking technologies that will underpin future high-speed networks. This paper provides an overview of the goals and methodologies employed in AURORA, and points to some preliminary results from our first year of research, ranging from analytic results to experimental prototype hardware. This paper enunciates our targets, which include new software architectures, network abstractions, and hardware technologies, as well as applications for our work