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Kdump is a way to acquire a crashed Linux kernel dump, but finding documents that explain its usage and internals can be challenging. In this article, I'll examine the basics of kdump usage and look at the internals of kdump/kexec kernel implementation.
In the history of computer games, very few are as influential as Colossal Cave Adventure. Initially developed in 1976 by Will Crowther and expanded by Don Woods in 1977, Adventure was the first interactive fiction game and inspired countless other computer games. Adventure directly or indirectly led to the entire corpus of text-based adventure games, and by extension, graphical adventure games.
Academic researchers depend on a variety of highly specialized software to power their studies. The commercial software options in common use are expensive; either investigators must purchase a large number of licenses for common applications like data analysis tools, or they have to buy costly single licenses for specialized software, such as an application for a specific laboratory device.
Your company is going to release an internal project as open source. Congratulations! You know your code is ready, but are you ready for all your new responsibilities?
Once a project has been released as open source, your company is not only responsible for the project, but also for the community that will form around it. This often requires changes to the development/build/release workflow. This is not about the code per se; it's about all the processes and infrastructure that surround the code that make the open source project successful.
When I started learning R, I also needed to learn how to collect Twitter data and map it for research purposes. Despite the wealth of information on the internet about this topic, I found it difficult to understand what was involved in collecting and mapping Twitter data. Not only was I was a novice to R, but I was also unfamiliar with the technical terms in the various tutorials. Despite these barriers, I was successful! In this tutorial, I will break down how to collect Twitter data and display it on a map in a way that even novice coders can understand.
I have two active role-playing gaming (RPG) sessions going all the time. One is a traditional face-to-face game, and we play at my kitchen table. The other is played online via Google Hangouts and a website, Roll20.net.
I've noticed something interesting about the people whose names appear at the top of reporting structures in open organizations:
They tend to underestimate their influence.
Exhibit A: I was sitting across from the director of my department, asking for his thoughts on a new quarterly recognition program I was hoping we'd implement as a way of enhancing associate engagement. "And the prize could be lunch with you!" I exclaimed.
My director met me with silence and a skeptical look before stating bluntly, "That is not a prize."
Working with a database in a pressure-cooker production environment using an agile approach with tight deadlines can be a contradictory experience. As this article demonstrates, you can operationalize those many steps and prepare Postgres for any range of service. The key is Ansible, an open source automation engine for software provisioning, configuration management, and application deployment.
Are you interested in machine learning and want to learn how to program? That's why I started learning to code. In this article, I'll share a few of the best resources that helped me advance from building my first program to building my first neural network.
I worked professionally as a software developer for nine years before I committed any code to open source. It wasn't that I didn't want to participate. Rather, my self-doubt and fear of rejection stopped me from contributing.
Here we take a look at the most significant developments in the cloth simulator from the past few months. This work was based on the proposal found here. The code developed during this time is at the moment still in its own branch, but will be merged at some point during the 2.8 series.Mass Spring Model
With the old mass-spring model used by Blender, the user could have no independent control over bending and compression, or stretching and shearing. As shown in the image below, the tension and shearing springs were coupled together.
Also, a single linear spring was responsible for both bending and compression resistance, as can be observed in the animation below. Furthermore, the usage of linear springs for resisting bending, deviates significantly from actual cloth behavior, and even allows bends to be flipped to the opposite direction without any resistance.
(Cross-sectional view) This video shows that the same spring was responsible for providing both compression and bending resistance, by pushing opposite sides of a bend away from each other.
The new model has componentized springs, and the addition of angular bending springs. Combining these things, the user has complete control over every aspect of the cloth stiffness independently.
Tension springs shown in blue, compression springs shown in red, shear springs shown in cyan, and angular bending springs shown in green. (springs of same color translate to a single property in the UI)
Beyond that, the angular springs behave much more realistically, and are signed, meaning that the cloth is aware of the direction of the bend, thus not allowing it to get flipped.
(Cross-sectional view) Here in the new model it can be seen that a new dedicated angular spring was added specifically for bending, while the compression springs always stay flush with the cloth surface.
Below are comparisons of various aspects of the cloth model that were improved.
Comparison of the old cloth bending model (left) and the new model (right).
Comparison of the old combined isotropic cloth tension model (left) and the new componentized anisotropic stretch/shear model (right).
Plasticity is the most significant property of deformable materials that was missing from Blender’s cloth simulator. Plasticity is the property in which materials retain deformations after being subjected to stresses, and thus don’t return completely to their original shape. In addition to the improved mass-spring model, the inclusion of this property, is the final piece in enabling the simulation of virtually any known deformable sheet material.
The same simulation shown without plasticity (left), and with plasticity (right).
The “Dynamic Besemesh” feature allows the underlying cloth mesh animation to be used as the new rest shape on each frame, thus enabling effects where the cloth changes shape throughout the simulation. However, an issue arises when this feature is used in combination with pinning. Because the pins also utilize the underlying mesh state to determine vertex locations, one could not have independent control over the pin locations and the dynamic rest shape. Now support has been added for using another mesh (with identical topology) as the rest shape.
The video below demonstrates the described issue, and shows how one can now animate rest shape and pin locations independently.
From left to right: (Top row) Animated cloth mesh (before simulation); Simulated cloth using own mesh both for pinning and as dynamic rest shape; (Bottom row) Animated mesh used as rest shape; Simulated cloth using external rest shape mesh;
In this week's Top 5, we're learning to talk, learning new languages, and learning to quit.Top 5 articles of the week
Every developer knows the importance of following best security practices. But too often we cut corners, maybe because we have to work hard until those security practices sink in. Unfortunately, that usually takes something like seeing a security malpractice that's so bad it gets marked in indelible ink in our brains.
Open source software is nothing new in an age where even big tech giants are exploring and using it. More and more companies allow—if not outright encourage—employees to contribute to open source software on company hours. What's missing in open source, however, is high-quality, effective design.
It's difficult, even in retrospect, to know which came first for us: containers or a shift towards DevOps culture.
In the wake of recent terror attacks, people have questioned the role of tech companies in fighting terrorism online. We want to answer those questions head on. We agree with those who say that social media should not be a place where terrorists have a voice. We want to be very clear how seriously we take this — keeping our community safe on Facebook is critical to our mission.
In this post, we’ll walk through some of our behind-the-scenes work, including how we use artificial intelligence to keep terrorist content off Facebook, something we have not talked about publicly before. We will also discuss the people who work on counterterrorism, some of whom have spent their entire careers combating terrorism, and the ways we collaborate with partners outside our company.
Our stance is simple: There’s no place on Facebook for terrorism. We remove terrorists and posts that support terrorism whenever we become aware of them. When we receive reports of potential terrorism posts, we review those reports urgently and with scrutiny. And in the rare cases when we uncover evidence of imminent harm, we promptly inform authorities. Although academic research finds that the radicalization of members of groups like ISIS and Al Qaeda primarily occurs offline, we know that the internet does play a role — and we don’t want Facebook to be used for any terrorist activity whatsoever.
We believe technology, and Facebook, can be part of the solution.
We’ve been cautious, in part because we don’t want to suggest there is any easy technical fix. It is an enormous challenge to keep people safe on a platform used by nearly 2 billion every month, posting and commenting in more than 80 languages in every corner of the globe. And there is much more for us to do. But we do want to share what we are working on and hear your feedback so we can do better.
We want to find terrorist content immediately, before people in our community have seen it. Already, the majority of accounts we remove for terrorism we find ourselves. But we know we can do better at using technology — and specifically artificial intelligence — to stop the spread of terrorist content on Facebook. Although our use of AI against terrorism is fairly recent, it’s already changing the ways we keep potential terrorist propaganda and accounts off Facebook. We are currently focusing our most cutting edge techniques to combat terrorist content about ISIS, Al Qaeda and their affiliates, and we expect to expand to other terrorist organizations in due course. We are constantly updating our technical solutions, but here are some of our current efforts.
- Image matching: When someone tries to upload a terrorist photo or video, our systems look for whether the image matches a known terrorism photo or video. This means that if we previously removed a propaganda video from ISIS, we can work to prevent other accounts from uploading the same video to our site. In many cases, this means that terrorist content intended for upload to Facebook simply never reaches the platform.
- Language understanding: We have also recently started to experiment with using AI to understand text that might be advocating for terrorism. We’re currently experimenting with analyzing text that we’ve already removed for praising or supporting terrorist organizations such as ISIS and Al Qaeda so we can develop text-based signals that such content may be terrorist propaganda. That analysis goes into an algorithm that is in the early stages of learning how to detect similar posts. The machine learning algorithms work on a feedback loop and get better over time.
- Removing terrorist clusters: We know from studies of terrorists that they tend to radicalize and operate in clusters. This offline trend is reflected online as well. So when we identify Pages, groups, posts or profiles as supporting terrorism, we also use algorithms to “fan out” to try to identify related material that may also support terrorism. We use signals like whether an account is friends with a high number of accounts that have been disabled for terrorism, or whether an account shares the same attributes as a disabled account.
- Recidivism: We’ve also gotten much faster at detecting new fake accounts created by repeat offenders. Through this work, we’ve been able to dramatically reduce the time period that terrorist recidivist accounts are on Facebook. This work is never finished because it is adversarial, and the terrorists are continuously evolving their methods too. We’re constantly identifying new ways that terrorist actors try to circumvent our systems — and we update our tactics accordingly.
- Cross-platform collaboration: Because we don’t want terrorists to have a place anywhere in the family of Facebook apps, we have begun work on systems to enable us to take action against terrorist accounts across all our platforms, including WhatsApp and Instagram. Given the limited data some of our apps collect as part of their service, the ability to share data across the whole family is indispensable to our efforts to keep all our platforms safe.
AI can’t catch everything. Figuring out what supports terrorism and what does not isn’t always straightforward, and algorithms are not yet as good as people when it comes to understanding this kind of context. A photo of an armed man waving an ISIS flag might be propaganda or recruiting material, but could be an image in a news story. Some of the most effective criticisms of brutal groups like ISIS utilize the group’s own propaganda against it. To understand more nuanced cases, we need human expertise.
- Reports and reviews: Our community — that’s the people on Facebook — helps us by reporting accounts or content that may violate our policies — including the small fraction that may be related to terrorism. Our Community Operations teams around the world — which we are growing by 3,000 people over the next year — work 24 hours a day and in dozens of languages to review these reports and determine the context. This can be incredibly difficult work, and we support these reviewers with onsite counseling and resiliency training.
- Terrorism and safety specialists: In the past year we’ve also significantly grown our team of counterterrorism specialists. At Facebook, more than 150 people are exclusively or primarily focused on countering terrorism as their core responsibility. This includes academic experts on counterterrorism, former prosecutors, former law enforcement agents and analysts, and engineers. Within this specialist team alone, we speak nearly 30 languages.
- Real-world threats: We increasingly use AI to identify and remove terrorist content, but computers are not very good at identifying what constitutes a credible threat that merits escalation to law enforcement. We also have a global team that responds within minutes to emergency requests from law enforcement.
Partnering with Others
Working to keep terrorism off Facebook isn’t enough because terrorists can jump from platform to platform. That’s why partnerships with others — including other companies, civil society, researchers and governments — are so crucial.
- Industry cooperation: In order to more quickly identify and slow the spread of terrorist content online, we joined with Microsoft, Twitter and YouTube six months ago to announce a shared industry database of “hashes” — unique digital fingerprints for photos and videos — for content produced by or in support of terrorist organizations. This collaboration has already proved fruitful, and we hope to add more partners in the future. We are grateful to our partner companies for helping keep Facebook a safe place.
- Governments: Governments and inter-governmental agencies also have a key role to play in convening and providing expertise that is impossible for companies to develop independently. We have learned much through briefings from agencies in different countries about ISIS and Al Qaeda propaganda mechanisms. We have also participated in and benefited from efforts to support industry collaboration by organizations such as the EU Internet Forum, the Global Coalition Against Daesh, and the UK Home Office.
- Encryption. We know that terrorists sometimes use encrypted messaging to communicate. Encryption technology has many legitimate uses – from protecting our online banking to keeping our photos safe. It’s also essential for journalists, NGO workers, human rights campaigners and others who need to know their messages will remain secure. Because of the way end-to-end encryption works, we can’t read the contents of individual encrypted messages — but we do provide the information we can in response to valid law enforcement requests, consistent with applicable law and our policies.
- Counterspeech training: We also believe challenging extremist narratives online is a valuable part of the response to real world extremism. Counterspeech comes in many forms, but at its core these are efforts to prevent people from pursuing a hate-filled, violent life or convincing them to abandon such a life. But counterspeech is only effective if it comes from credible speakers. So we’ve partnered with NGOs and community groups to empower the voices that matter most.
- Partner programs: We support several major counterspeech programs. For example, last year we worked with the Institute for Strategic Dialogue to launch the Online Civil Courage Initiative, a project that has engaged with more than 100 anti-hate and anti-extremism organizations across Europe. We’ve also worked with Affinis Labs to host hackathons in places like Manila, Dhaka and Jakarta, where community leaders joined forces with tech entrepreneurs to develop innovative solutions to push back against extremism and hate online. And finally, the program we’ve supported with the widest global reach is a student competition organized through the P2P: Facebook Global Digital Challenge. In less than two years, P2P has reached more than 56 million people worldwide through more than 500 anti-hate and extremism campaigns created by more than 5,500 university students in 68 countries.
We want Facebook to be a hostile place for terrorists. The challenge for online communities is the same as it is for real world communities – to get better at spotting the early signals before it’s too late. We are absolutely committed to keeping terrorism off our platform, and we’ll continue to share more about this work as it develops in the future.
By Elliot Schrage, Vice President for Public Policy and Communications
Today we’re starting something new.
Facebook is where people post pictures with their friends, get their news, form support groups and hold politicians to account. What started out as a way for college students in the United States to stay in touch is now used by nearly 2 billion people around the world. The decisions we make at Facebook affect the way people find out about the world and communicate with their loved ones.
It goes far beyond us. As more and more of our lives extend online, and digital technologies transform how we live, we all face challenging new questions — everything from how best to safeguard personal privacy online to the meaning of free expression to the future of journalism worldwide.
We debate these questions fiercely and freely inside Facebook every day — and with experts from around the world whom we consult for guidance. We take seriously our responsibility — and accountability — for our impact and influence.
We want to broaden that conversation. So today, we’re starting a new effort to talk more openly about some complex subjects. We hope this will be a place not only to explain some of our choices but also explore hard questions, such as:
- How should platforms approach keeping terrorists from spreading propaganda online?
- After a person dies, what should happen to their online identity?
- How aggressively should social media companies monitor and remove controversial posts and images from their platforms? Who gets to decide what’s controversial, especially in a global community with a multitude of cultural norms?
- Who gets to define what’s false news — and what’s simply controversial political speech?
- Is social media good for democracy?
- How can we use data for everyone’s benefit, without undermining people’s trust?
- How should young internet users be introduced to new ways to express themselves in a safe environment?
As we proceed, we certainly don’t expect everyone to agree with all the choices we make. We don’t always agree internally. We’re also learning over time, and sometimes we get it wrong. But even when you’re skeptical of our choices, we hope these posts give a better sense of how we approach them — and how seriously we take them. And we believe that by becoming more open and accountable, we should be able to make fewer mistakes, and correct them faster.
Our first substantive post, later today, will be about responding to the spread of terrorism online — including the ways we’re working with others and using new technology.
We want your input on what other topics we should address — and what we could be doing better. Please send suggestions to email@example.com.
Being able to edit your $PATH is an important skill for any beginning Linux user.
For some time now, Archphile has been my go-to Linux distro for my home music servers. I'm very sad to say that it appears Archphile is no longer, or at least so its website suggests.
Impact mapping is a technique for building shared understanding between leaders and project teams. Delivered in an engaging workshop format, impact mapping is the perfect way to initiate a work stream in a way that encourages innovation. Gojko Adzic first documented the technique in a 2011 brochure; it's an excellent guide for individuals who want to facilitate the workshop. This article aims to complement Adzic's original text with a guide for leaders who want to sponsor impact mapping initiatives but may not facilitate the workshops themselves.