Link Clearance

Man it was hot today. Doesn't fall mean that it starts to cool down?

• The Physics of Doing an Ollie on a Skateboard, or, the Science of Why I Can’t Skate

  So here’s a thought – maybe I can use physics to learn how to do an ollie. Here’s the plan. I’m going to open up the above video of skateboarder Adam Shomsky doing an ollie, filmed in glorious 1000 frames-per-second slow motion, and analyze it in the open source physics video analysis tool Tracker.

• 11th USENIX Symposium on Operating Systems Design and Implementation (OSDI '14).

  As part of our commitment to open access, the proceedings from the Symposium are now free and openly accessible via the technical sessions Web page.

• The Horror of a 'Secure Golden Key'

  A “golden key” is just another, more pleasant, word for a backdoor—something that allows people access to your data without going through you directly. This backdoor would, by design, allow Apple and Google to view your password-protected files if they received a subpoena or some other government directive. You'd pick your own password for when you needed your data, but the companies would also get one, of their choosing. With it, they could open any of your docs: your photos, your messages, your diary, whatever.

• Malware needs to know if it's in the Matrix

  A presentation from UCSM's professor Giovanni Vigna (who runs the Center for CyberSecurity and Seclab), he's seeing more and more malware that keeps its head down on new infection sites, cautiously probing the operating system to try and determine if it's running on a real computer or if it's a head in a jar, deploying all kinds of tricks to get there.

• 44 engineering management lessons

  30. Most conflict happens because people don’t feel heard. Sit down with each person and ask them how they feel. Listen carefully. Then ask again. And again. Then summarize what they said back to them. Most of the time that will solve the problem.

• Unlocked 10Gbps TX wirespeed smallest packet single core

  The single core 14.8Mpps performance number is an artificial benchmark performed with pktgen, which besides spinning the same packet (skb), now also notifies the NIC hardware after populating it's TX ring buffer with a "burst" of packets.

• Redis cluster, no longer vaporware.

  The consistency model is the famous “eventual consistency” model. Basically if nodes get desynchronized because of partitions, it is guaranteed that when the partition heals, all the nodes serving a given key will agree about its value.

  However the merge strategy is “last failover wins”, so writes received during network partitions can be lost. A common example is what happens if a master is partitioned into a minority partition with clients trying to write to it. If when the partition heals, in the majority side of the partition a slave was promoted to replace this master, the writes received by the old master are lost.

• Using Git Hunks

  Many of the git subcommands can be passed --patch or -p for short. When used with git add, we can compose a commit with exactly the changes we want, instead of just adding whole files. Once you hit enter, you get an interactive prompt where you're presented with a diff and a set of options.

• Slasher Ghost, and Other Developments in Proof of Stake

  The fundamental problem that consensus protocols try to solve is that of creating a mechanism for growing a blockchain over time in a decentralized way that cannot easily be subverted by attackers. If a blockchain does not use a consensus protocol to regulate block creation, and simply allows anyone to add a block at any time, then an attacker or botnet with very many IP addresses could flood the network with blocks, and particularly they can use their power to perform double-spend attacks – sending a payment for a product, waiting for the payment to be confirmed in the blockchain, and then starting their own “fork” of the blockchain, substituting the payment that they made earlier with a payment to a different account controlled by themselves, and growing it longer than the original so everyone accepts this new blockchain without the payment as truth.

• Economies of Scale in Peer-to-Peer Networks

  I've been working on P2P technology for more than 16 years, and although I believe it can be very useful in some specific cases, I'm far less enthusiastic about its potential to take over the Internet.

  Below the fold I look at some of the fundamental problems standing in the way of a P2P revolution, and in particular at the issue of economies of scale.

• A Scalability Roadmap

  You might be surprised that old blocks aren’t needed to validate new transactions. Pieter Wuille re-architected Bitcoin Core a few releases ago so that all of the data needed to validate transactions is kept in a “UTXO” (unspent transaction output) database. The amount of historical data needed that absolutely must be stored depends on the plausible depth of a blockchain reorganization. The longest reorganization ever experienced on the main network was 24 blocks during the infamous March 11, 2013 chain fork.

• Why the Trolls Will Always Win

  But here’s the key: it turned out he wasn’t outraged about my work. His rage was because, in his mind, my work didn’t deserve the attention. Spoiler alert: “deserve” and “attention” are at the heart.