Lecture

Redundancy in Dependable Systems

Graph Chat

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

In course

CS-522: Principles of computer systems

This advanced graduate course teaches the key design principles underlying successful computer and communication systems, and shows how to solve real problems with ideas, techniques, and algorithms from operating systems, networks, databases, programming l ...

Description

This lecture delves into the concept of redundancy as a key technique for constructing dependable systems, complementing modularity. The instructor explains how redundancy involves duplicating components with a purpose to increase dependability, and how it is used to achieve fault tolerance, reliability, and high availability. The lecture covers the definitions of faults, errors, and failures, as well as the importance of fault models in reasoning about system failures. Various forms of redundancy, such as data redundancy and functional redundancy, are explored, along with the use of leases to prevent resource leaks. The discussion also touches on the significance of idempotency in ensuring reliable system recovery and the role of leases in guaranteeing the absence of resource leaks.

Instructor

George Candea

George Candea heads the Dependable Systems Lab, where he develops techniques and abstractions for building efficient and trustworthy computer systems. His current work focuses on making performance and energy programmable, i.e., providing first-class abstractions to capture a system’s performance and energy behavior (as interfaces do for functionality) and to use them dependably to design, code, and operate efficient systems.In the recent past, George also served as CEO and later Chief Scientist of Cyberhav

Official source

Related concepts (32)

Reliability engineering

Reliability engineering is a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability describes the ability of a system or component to function under stated conditions for a specified period of time. Reliability is closely related to availability, which is typically described as the ability of a component or system to function at a specified moment or interval of time. The reliability function is theoretically defined as the probability of success at time t, which is denoted R(t).

Triple modular redundancy

In computing, triple modular redundancy, sometimes called triple-mode redundancy, (TMR) is a fault-tolerant form of N-modular redundancy, in which three systems perform a process and that result is processed by a majority-voting system to produce a single output. If any one of the three systems fails, the other two systems can correct and mask the fault. The TMR concept can be applied to many forms of redundancy, such as software redundancy in the form of N-version programming, and is commonly found in fault-tolerant computer systems.

Color

Color (American English) or colour (Commonwealth English) is the visual perception based on the electromagnetic spectrum. Though color is not an inherent property of matter, color perception is related to an object's light absorption, reflection, emission spectra and interference. For most humans, color are perceived in the visible light spectrum with three types of cone cells (trichromacy). Other animals may have a different number of cone cell types or have eyes sensitive to different wavelength, such as bees that can distinguish ultraviolet, and thus have a different color sensitivity range.

Knapsack problem

The knapsack problem is the following problem in combinatorial optimization: Given a set of items, each with a weight and a value, determine which items to include in the collection so that the total weight is less than or equal to a given limit and the total value is as large as possible. It derives its name from the problem faced by someone who is constrained by a fixed-size knapsack and must fill it with the most valuable items.

Color theory

In the visual arts, color theory is the body of practical guidance for color mixing and the visual effects of a specific color combination. Color terminology based on the color wheel and its geometry separates colors into primary color, secondary color, and tertiary color. The understanding of color theory dates to antiquity. Aristotle (d. 322 BCE) and Claudius Ptolemy (d. 168 CE) already discussed which and how colors can be produced by mixing other colors. The influence of light on color was investigated and revealed further by al-Kindi (d.

Related lectures (43)

Dependability Overview

Explores dependability in industrial automation, covering reliability, safety, fault characteristics, and examples of failure sources in various industries.

LED, Light and Color

Covers the energy and radiation of LEDs, transitions in energy levels, and color synthesis.

Dependable Architectures and Software

Explores dependable architectures, error detection, fault-tolerant structures, and software reliability through examples like the Patriot Missile failure and ABB dual controller.

Ramanujan Graphs: Generating Functions and Expander Graphs

Explores Ramanujan graphs, generating functions, non-backtracking walks, and expander graphs in relation to NP-hard problems.

Designing Spaces: Movement and Architecture