Systèmes d'exploitation et cloud

This document provides an in-depth exposition of the GNU/Linux file management system. It elaborates on the structure and types of files, such as regular, directories, special files, symbolic links, and interprocess communication objects like pipes and sockets. Key aspects covered include the file metadata stored in inodes, file permissions and access control using chmod and umask, and the distinct hierarchical file system structure adhering to FHS standards. It also explores task scheduling mechanisms like cron and at, emphasizing system administration utilities and best practices for user...

This document provides an in-depth overview of cloud computing service models such as IaaS, PaaS, and SaaS, alongside deployment models including private, public, hybrid, and community clouds. Definitions and examples of key cloud functionalities—such as runtimes, middleware, object vs block storage, and virtual networking—are explained, with detailed comparisons and use cases. It highlights technical aspects of IaaS, including storage types (block/object), network features like Amazon's VPC, and major global and regional cloud providers. Methodologies such as data replication and erasure c...

The document outlines practical activities for Linux system administration, including using terminal commands to manage shutdowns, dates, and system logs, modifying system files for automated task execution, and configuring the GRUB boot menu. It emphasizes scripting, system kernel settings, and user-specific configurations as part of foundational system management. Detailed steps are provided for maintenance, troubleshooting, and kernel memory management focused on user-centered data.

This document constitutes a technical assignment focused on fundamental development tools under a Linux environment. It involves writing and testing C programs to calculate the remainder of a division and the power of a number using command-line input, along with error handling for arguments. Additional tasks include using GCC compiler commands to explore preprocessing and executable generation outputs, creating standalone functions, writing a library for modular programming, and integrating it into a new program. The document emphasizes hands-on coding, testing, and debugging for skill acq...

This document presents a structured exercise analyzing the behavior and causality of events in a distributed system. It includes tasks to calculate logical clocks, vector clocks, and matrix clocks for given processes and to identify undelivered messages within the system. The exercise integrates tabular data to assess event dependencies and provides a real-world application of system synchronization methods. The calculations are geared toward understanding the temporal relationships in concurrent operations.

This document outlines a series of exercises focused on analyzing and applying clock synchronization and causality in distributed systems. It includes tasks like studying event causality, computing logical and vector clocks, identifying delivery failures, and applying matrix clocks. The exercises aim to deepen understanding of event sequencing and timing within distributed environments.

The document provides a comprehensive overview of key concepts in cloud computing, focusing on service models like SaaS, PaaS, and IaaS, and deployment models such as private, public, hybrid, and community clouds. It details the benefits, features, and examples of SaaS with case studies on popular platforms like Salesforce and Microsoft Office 365. Security concerns, usability, and functionality of hybrid and multi-cloud environments are also discussed, highlighting use cases including data security, Big Data analytics, and dynamic scalability through cloud bursting. The document concludes...

Platform as a Service (PaaS) provides a managed development environment hosted by external providers, offering flexibility and scalability compared to traditional development setups. It eliminates the need for manual configuration, supports multiple tenants, and is typically available via a web browser. Notable examples include Cloud9 by AWS and Bluemix by IBM, complemented by open-source tools like CloudFoundry. PaaS simplifies development processes, enhances the availability of tools and runtimes, and integrates modern practices like DevOps for streamlined collaboration and continuous del...

This document explores virtualization in computing, detailing key methodologies such as full virtualization, para-virtualization, and containerization. Full virtualization emulates entire physical machines, while para-virtualization uses modified operating systems for performance enhancements. Isolation techniques like chroot and LXC introduce lightweight, resource-efficient environments leading to containerization, which optimizes application hosting. Performance comparisons highlight benefits of containerization over traditional virtualization for resource utilization and scalability.

The document provides an in-depth exploration of virtualization methodologies, focusing on hypervisors, types of virtualization, and major software solutions like XEN, KVM, and VMware. It analyzes storage virtualization and its applications, transitioning toward cloud computing models such as SAAS, PAAS, and IAAS. Cloud architectures, including private, public, and hybrid, are discussed along with their benefits. The main cloud service providers such as Amazon, Microsoft, and Google are compared. The report concludes by examining the integration of these technologies into modern IT infrastr...

The study addresses the optimization of scheduling independent tasks on heterogeneous processors to minimize makespan through load balancing. Key metrics include the weighted processor load (CHP) and the maximum load across processors (M). Two primary scheduling principles are discussed, alongside three iterative algorithms (LS, SPT, LPT) each with two variations based on the given principles. Improvements are proposed via heuristic adjustments that reassign tasks between processors to achieve better load distribution. Comparative analyses establish the superiority of Principle 2 over Princ...

The document focuses on task scheduling and the dependencies involved between tasks in a computational context. It categorizes dependencies into three types: producer-consumer dependencies, consumer-producer (anti-dependencies), and producer-producer (output dependencies). Specific examples are provided to illustrate each type of dependency alongside respective precedence rules. Additionally, a remark highlights the sequential order of program execution governing dependency precedence.

This document explores the methodology of task scheduling by structuring dependencies into a sequence. It defines input-output relationships of tasks, identifies dependencies categorized as producer-consumer, consumer-producer, or producer-producer. Redundant dependencies are removed through transitivity. The approach concludes with a dependency graph identifying critical tasks and their optimal order.

The document analyzes task scheduling using precedence and execution trees for associative expressions. Two versions of scheduling, early (Version 1) and late (Version 2), are compared through sequential time (T1) and parallel efficiencies (S3, E3 for Version 1; S2, E2 for Version 2). Version 2 is shown to outperform Version 1 based on efficiency comparisons. The document concludes that late task scheduling reduces processing inefficiencies.