We present HotStuff, a leader-based Byzantine fault-tolerant replication protocol for the partially synchronous model.

Once network communication becomes synchronous, HotStuff enables a correct leader to drive the protocol to consensus at the pace of actual (vs. maximum) network delay--a property called responsiveness--and with communication complexity that is linear in the number of replicas. To our knowledge, HotStuff is the first partially synchronous BFT replication protocol exhibiting these combined properties. HotStuff is built around a novel framework that forms a bridge between classical BFT foundations and blockchains. It allows the expression of other known protocols (DLS, PBFT, Tendermint, Casper), and ours, in a common framework.

Our deployment of HotStuff over a network with over 100 replicas achieves throughput and latency comparable to that of BFT-SMaRt, while enjoying linear communication footprint during leader failover (vs. quadratic with BFT-SMaRt).

by Ben Laurie

The modern world doesn’t look like this at all. All the files on a typical computer belong to a non-expert user (for simplicity I am ignoring shared devices — this doesn’t really undermine the argument as I hope you will see). Indeed, the whole computer typically belongs to a single user. Printers do not need accounting and similarly belong to the same user. The enemy is the software that is running on the machine. Users no longer have a good understanding of the software they run. Software is enormously complex and uses all sorts of resources, many distributed over multiple systems, to accomplish their tasks. And frequently their task is only superficially in service of the user.

In short, the old threat model was untrusted tenants, trusted software, unit of protection is files and devices. The new threat model is trusted tenants, untrusted software, unit of protection is individual data items.

It’s 9 a.m. on a typical morning in Chengdu and I’m awakened by the sound of my phone alarm. The phone is in my study, connected to my bedroom by sliding doors. I turn off the alarm, pick up my phone, and, like millions of people in China, the first thing I do is check my WeChat. At 9:07, I send my first message of the day.

Before 10 on a normal day in Chengdu, WeChat knows the following things about me: It knows roughly when I wake up, it knows who has messaged me and who I message, it knows what we talk about. It knows my bank details, it knows my address and it knows my coffee preference in the morning. It knows my biometric information; it knows the very contours of my face.

Many games depend on content variety to tailor their gameplay experience. Having repetitive challenges can lead to player boredom, so designers generally aim to create an experience that is constantly engaging. Games usually consist of many facets such as levels, mechanics, graphics, sounds, etc. One of the most unique is level design. It does not introduce a new dimension in the game, instead, it is concerned with the arrangement of the existing elements. With the high demand for content in games, level design becomes a major task in game design. Its role is of pivotal importance, to the extent of being assigned to a different team than the one responsible for game and mechanics design, for games with large scopes.

This video demonstrates the concept of series-elastic actuators (SEAs) and how they are used in rehabilitation robotics.

Technology reshapes the workplace in much subtler ways than simply robots stealing jobs.

Developed in China, the lidar-based system can cut through city smog to resolve human-sized features at vast distances.

Rebuttal to the opinion of Christoph Buchal, Hans-Dieter Karl and Hans-Werner Sinn titled “Coal Engines, Wind Engines and Diesel Engines. What does the CO2 balance show?”

Alpine Linux-based Docker images are small, but they can still bloat up quickly. If you're concerned about image size, search for alternatives, like Minideb.

When the Docker revolution started, one argument among many in favor of using containers instead of virtual machines was their size. Container images were supposed to be small.

However, several anti-patterns quickly emerged in the early days of Docker. First, most people wanted to treat containers just like VMs, hence they wanted an SSH server in them, they wanted to run multiple processes in them and they wanted their regular Linux distributions.

This quickly ballooned the size of Docker images that could be pulled from the Docker Hub. Official Ubuntu and CentOS images used to be above 600 MB. Once dependencies and application code got added, it was not rare to see several GB Docker images around.

Deep dive into Go Memory Management. This post gives an overview of Physical memory, Virtual memory, how Operating System interacts with hardware to run applications.

Le rivoluzioni del passato hanno permesso di aumentare la ricchezza, ridurre la povertà e migliorare la qualità della vita.

Questa ricerca, presentata nel corso della 43° edizione del Forum “Lo Scenario di oggi e di domani per le strategie competitive”, nasce con l’obiettivo di analizzare lo sce­nario attuale e gli impatti futuri dell’automazione sul mercato del lavoro italiano, …

Mathematics is all around us, and it has shaped our understanding of the world in countless ways.

In 2013, mathematician and science author Ian Stewart published a book on 17 Equations That Changed The World. We recently came across this convenient table on Dr. Paul Coxon’s twitter account by mathematics tutor and blogger Larry Phillips that summarizes the equations.

Our New Year’s guide to hacker-friendly single board computers turned up 90 boards, ranging from powerful media playing rigs to power-sipping IoT platforms.

Community backed, open spec single board computers running Linux and Android sit at the intersection between the commercial embedded market and the open source maker community. Hacker boards also play a key role in developing the Internet of Things devices that will increasingly dominate our technology economy in the coming years, from home automation devices to industrial equipment to drones.

This year, we identified 90 boards that fit our relatively loose requirements for community-backed, open spec SBCs running Linux and/or Android. This is up from 81 boards in our similar catalog of hacker boards, posted June 1, which was followed later that month by a survey in which readers picked their favorite boards. A year ago in our New Year’s catalog we showcased 64 boards, up from 53, 40, and 32 entries in our previous reports.

Our annual winter round-up does not include a reader survey, which acts as a mid-year update, but below you will find individual summaries of all 90 SBCs with the most recent prices and updates. We also supply links to LinuxGizmos coverage and project websites, plus an extensive comparison table of major features of all 90 boards.

A British company thought to be working closely with Apple has created a hydrogen fuel cell for an iPhone 6 that allows the device to go a week without recharging.