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At Cerner, we use Chef to automate our deployments across a very large distributed system comprised of many thousands of nodes. While we employ ServerSpec and Test Kitchen extensively to test our Chef recipes, this still doesn’t identify all possible failure scenarios. In a large distributed system such as ours, we occasionally run into connectivity failures between machines due to network ACL issues. This could be due to a variety of reaso..
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This is a simple JavaScript game I made a while ago using HTML5’s canvas element. The rules are simple: Click on a box when it appears to make it disappear. Every time you click a box, you get points. However, every time you click a box, the next one appears faster. If a box appears on top of another box, you lose points. “Peak” is the highest score you achieved before you started losing points.
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I've open-sourced my mongodb/couchdb data integrity analysis tool called white glove. You can find it at focusaurus/white-glove on github and white-glove on npm . It helps with both schema discovery of a new or unfamiliar database as well as scanning your data for inconsistencies that may help you prevent problems before they cause any impact to end users.
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Build a simple distributed system using AWS Lambda, Python, and DynamoDB
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tech.nextroll.com
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10 years ago
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eng
We have implemented a number of systems in support of our Erlang -based real-time bidding platform. One of these is a Celery task system which runs code implemented in Python on a set of worker instances running on Amazon EC2 . With the recent announcement of built-in support for Python in AWS Lambda functions (and upcoming access to VPC resources from Lambda), we’ve started considering increased use of Lambda for a number o....
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Disclaimer : All salaries and bonuses in this post – even those based on real paychecks – are entirely fictional. All financial information is paraphrased…..poorly. The following post was written by a 23-year old man who lives in a truck entirely of his own volition and holds a degree in something wholly-unrelated to both business and finance. As such, its content should not be viewed or seriously considered as advice by anyone.
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Disclaimer : All salaries and bonuses in this post – even those based on real paychecks – are entirely fictional. All financial information is paraphrased…..poorly. The following post was written by a 23-year old man who lives in a truck entirely of his own volition and holds a degree in something wholly-unrelated to both business and finance. As such, its content should not be viewed or seriously considered as advice by anyone.
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Some concepts are very complex and need a long explanation. But we might decide to take a shortcut and simplify the concept when describing it. That short explanation is misleading. Lets see why… For example, we might be trying to explain electro-magnetism. A full explanation will include Maxwell’s equations, definitions of electric and magnetic fields a discussion of ferromagnets, and more. A shortcut explanation might be that magnet....
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Cliff Sloane's asian classical music in mp3 format . Oriental traditional music . Shruti Box comparison .
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LiveReload is a fantastic feature to add to your development workflow to increase your productivity. The general idea is that when a change occurs to a file that makes up your app, your app is automatically rebuilt and the app restarts itself. This saves you from manually rebuilding and restarting your app each time you make a change and generally makes development much more pleasant. There are LiveReload implementations available for many ..
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An opinionated Sass architecture system for writing modular and scalable libraries. Also, a case in defense of extends.
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Notes from the book: JavaScript: The Good Parts by Douglas Crockford Index JavaScript: The Good Parts Primitives Execution Flow Equality Loops / Enumeration Object Literals Arrays Delete Global Abatement Reference Reflection Functions Prototype Function Invocation Pattern Constructor Invocation pattern Closure Modules WTF JavaScript: The Good Parts A walkthrough many of the useful code examples fr....
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Putting together an continuous-integration-style automated build and deploy halfway through the project is exponentially more effort than starting off with one. At some point in the project, it may even be that the effort outweighs the gain.
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We’re constantly clicking on all sorts of different URL’s throughout the day. These clickable links appear in webpages (including in “ web apps ” like gmail) in mail clients like Evolution , in terminals such as GNOME-terminal , and any other GTK+ app on your GNU/Linux desktop. I wanted to perform custom actions when arbitrary URL’s are clicked, including running certain links in separate Firefox profiles. There are a bunch of different..
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We’re constantly clicking on all sorts of different URL’s throughout the day. These clickable links appear in webpages (including in “ web apps ” like gmail) in mail clients like Evolution , in terminals such as GNOME-terminal , and any other GTK+ app on your GNU/Linux desktop. I wanted to perform custom actions when arbitrary URL’s are clicked, including running certain links in separate Firefox profiles. There are a bunch of different..
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Note: I’ve never seen Game of Thrones, but I’m pretty sure the title is a reference to it. When I was a kid, I used to watch my dad plow driveways and parking lots. He’d be out in the middle of a blizzard, wearing a sweatshirt (at most), carving out huge scoops of snow and heaving them over his shoulder. In moments like those, I thought he was a true-to-life superhero. So naturally it’s no shock that I inherited his lust for needless fea....
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Note: I’ve never seen Game of Thrones, but I’m pretty sure the title is a reference to it. When I was a kid, I used to watch my dad plow driveways and parking lots. He’d be out in the middle of a blizzard, wearing a sweatshirt (at most), carving out huge scoops of snow and heaving them over his shoulder. In moments like those, I thought he was a true-to-life superhero. So naturally it’s no shock that I inherited his lust for needless fea....
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A Quasipolynomial Time Algorithm for Graph Isomorphism: The Details
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www.jeremykun.com
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10 years ago
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eng
Update 2017-01-09: Laci claims to have found a workaround to the previously posted error, and the claim is again quasipolynoimal time! Updated arXiv paper to follow. Update 2017-01-04: Laci has posted an update on his paper. The short version is that one small step of his analysis was not quite correct, and the result is that his algorithm is sub-exponential, but not quasipolynomial time. The fact that this took over a year to sort out is a..
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A Quasipolynomial Time Algorithm for Graph Isomorphism: The Details
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www.jeremykun.com
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10 years ago
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eng
Update 2017-01-09: Laci claims to have found a workaround to the previously posted error, and the claim is again quasipolynoimal time! Updated arXiv paper to follow. Update 2017-01-04: Laci has posted an update on his paper. The short version is that one small step of his analysis was not quite correct, and the result is that his algorithm is sub-exponential, but not quasipolynomial time. The fact that this took over a year to sort out is a..
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A Quasipolynomial Time Algorithm for Graph Isomorphism: The Details
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www.jeremykun.com
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10 years ago
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eng
Update 2017-01-09: Laci claims to have found a workaround to the previously posted error, and the claim is again quasipolynoimal time! Updated arXiv paper to follow. Update 2017-01-04: Laci has posted an update on his paper. The short version is that one small step of his analysis was not quite correct, and the result is that his algorithm is sub-exponential, but not quasipolynomial time. The fact that this took over a year to sort out is a..
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Rollup: How we use React.js and npm to share UI code at AdRoll
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tech.nextroll.com
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10 years ago
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eng
This is the second in a series of three blog posts about Rollup, AdRoll’s UI component library. This post covers how we build individual components and the developer tools supporting them. For background on why we built a UI component library, see last week’s post . For a discussion on what we learned from building Rollup see next week’s post . All the shared UI components we use at AdRoll live in a private GitHub repository called Rol....
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I have a quite large iTunes library, and I’m rather anal about keeping my metadata clean and up to date. In an earlier release of iTunes 12 there was a bug. Every so often after a song played, the Play Count would fail to increment, but the Last Played would update. Searching my library, I found 74 tracks that had this issue. I found this irritating and inaccurate, so I set forth finding a way to correct it. I wrote the following sim..
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I have a quite large iTunes library, and I’m rather anal about keeping my metadata clean and up to date. In an earlier release of iTunes 12 there was a bug. Every so often after a song played, the Play Count would fail to increment, but the Last Played would update. Searching my library, I found 74 tracks that had this issue. I found this irritating and inaccurate, so I set forth finding a way to correct it. I wrote the following sim..
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For those who haven't used Emacs, it's something you'll likely hate, but may love. It's sort of a Rube Goldberg machine the size of a house that, at first glance, performs all the functions of a toaster.
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Troubleshooting Another Complex Performance Issue – Oracle direct path inserts and SEG$ contention
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tanelpoder.com
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10 years ago
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eng
Here’s an updated presentation I first delivered at Hotsos Symposium 2015. It’s about lots of concurrent PX direct path insert ant CTAS statements that, when clashing with another bug/problem, caused various gc buffer busy waits and enq: TX – allocate ITL entry contention. This got amplified thanks to running this concurrent workload on 4 RAC nodes: When reviewing these slides, I see there’s quite a lot that needs to be said in..
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Troubleshooting Another Complex Performance Issue – Oracle direct path inserts and SEG$ contention
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tanelpoder.com
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10 years ago
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eng
Here’s an updated presentation I first delivered at Hotsos Symposium 2015. It’s about lots of concurrent PX direct path insert ant CTAS statements that, when clashing with another bug/problem, caused various gc buffer busy waits and enq: TX – allocate ITL entry contention. This got amplified thanks to running this concurrent workload on 4 RAC nodes: When reviewing these slides, I see there’s quite a lot that needs to be said in..
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So after having a Google Nexus 5 smartphone for the last 2+ years, when I saw that Project Fi had the potential to give me better coverage and a higher data limit for lower cost than T-Mobile, I decided to go for it. Here's my notes on both the Project Fi service and the Google Nexus 5X smartphone. Project Fi Value: great cheap data rates and my modest usage means I have basically all the data, TXT, and voice I need for $40/month ....
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I did some research on snail ailments. This particular page was especially useful. Though SnailLife snails are not aquatic, some of these still seem very relevant: http://applesnail.net/content/various/snail_disease.php Also did research on inbreeding in snails and complications it could cause. Apparently one commonly observed side effect is shell thinning. I then did some reading on finding the inbreeding coefficent and how to calculate ..
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My desk has a new ornament on it: an Arduino powered lamp. And why does that merit a blog post? Because I built it. After combining the Rainbowduino kit with some 600-ish points of solder, I found myself ruler of a 16MHz processor, 30Kb of instruction storage, 2Kb of data storage, and 64 tricolor pixels. And what does one do with 64 pixels, no inputs, and processing power reminiscent of a vintage entertainment console?
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