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Showing posts from June, 2012

This Blog Has Moved!

Right, so yes, five years ago I moved to github pages, and never bothered to redirect any of these pages there. Now I've moved on from there, and... Finally I am using my real domain, trishagee.com . My blog is now at trishagee.com/blog .  See you there!
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The subject of women programmers is boring

I've been challenged to do a session at a very large conference around women in programming.  Which leads to two reactions from me 1) wow, what an honour! and 2) *sigh*. The problem with these sessions is that you're preaching to the choir.  Those who turn up are a) women or b) men who are sympathetic and supportive to the cause.  People who are actively discriminating against women or, more commonly, those who don't know their actions are hurting diversity in our industry, are the least likely to receive the message. This tends to lead to the same types of sessions - yes, our industry under-represents certain segments of society (i.e. women); yes, we all agree this is a problem; yes, everyone in this room is trying their best to do the right things; no, we have no idea how to fix it at the industry-level. These sessions are boring . How do you make this subject interesting, relevant, and appeal to the types of people it really should target? I'm c
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Overheard: Development Myths

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Continuing the theme of Things I Have Heard I Don't Think I Agree With. To developers technologies are everything I can't remember the context of this but I hear the same sentiment in different guises over and over again.  Often from non-techies, but more alarmingly from developers. Is this true? It's true for a certain tribe of techies, sure.  And creating and effectively using new technologies is an important part of what drives the current information age forward.  But I'd be worried if I thought that 99% of developers were like this. In our day jobs, and also if we want to create something that makes any money, we need to be interested in solving people's problems and creating solutions.  Sure, we'll use technology to do that.  But if we were all only motivated by technology, we'd always be trying out the Next Big Thing when our customers wanted a simple CRUD web app.  Any organisation that encouraged this sort of technology um, infidelity?  pla
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The birth of a new community

Topping off my mini-tour at the end of May, I was invited to Rotterdam to  present to a brand new community of developers.  I was really interested in attending because my experience with user groups is pretty much limited to the London Java Community , and I knew this would be different due to being a) across a wider range of technologies and b) shiny and new. It was hosted (rather awesomely) in a brewery, and until then I'd never given a presentation in a pub.  Frankly it's something I'm keen to do more of.  Due to a total technology fail on the part of all of us, we couldn't get the projector working with any of the various laptops.  However, with 30-odd techies, free wireless and slides available on Slideshare , we managed a novel and collaborative presentation approach, with people clustered around the laptops with the largest screens, and someone at each one valiantly keeping up with my quick pace through over 100 slides of stick-men drawings ( a review of the
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QCon London: Disruptor presentation video

The "User's Guide to the Disruptor" presentation I gave at QCon London is now available on the  InfoQ site .  This is the same presentation as the one I gave at Skillsmatter in March , but the questions are different.  Plus since I'm winging it every time, I probably cover slightly different things or explain some stuff better / worse.
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Popular posts from this blog

Dissecting the Disruptor: What's so special about a ring buffer?

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Recently we open sourced the LMAX Disruptor , the key to what makes our exchange so fast.  Why did we open source it?  Well, we've realised that conventional wisdom around high performance programming is... a bit wrong. We've come up with a better, faster way to share data between threads, and it would be selfish not to share it with the world.  Plus it makes us look dead clever. On the site you can download a technical article explaining what the Disruptor is and why it's so clever and fast.  I even get a writing credit on it, which is gratifying when all I really did is insert commas and re-phrase sentences I didn't understand. However I find the whole thing a bit much to digest all at once, so I'm going to explain it in smaller pieces, as suits my  NADD audience. First up - the ring buffer.  Initially I was under the impression the Disruptor was just the ring buffer.  But I've come to realise that while this data structure is at the heart of the patte
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Dissecting the Disruptor: Writing to the ring buffer

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This is the missing piece in the end-to-end view of the Disruptor.  Brace yourselves, it's quite long.  But I decided to keep it in a single blog so you could have the context in one place. The important areas are: not wrapping the ring; informing the consumers; batching for producers; and how multiple producers work. ProducerBarriers The Disruptor code has interfaces and helper classes for the Consumer s, but there's no interface for your producer, the thing that writes to the ring buffer.  That's because nothing else needs to access your producer, only you need to know about it.  However, like the consuming side, a ProducerBarrier is created by the ring buffer and your producer will use this to write to it. Writing to the ring buffer involves a two-phase commit.  First, your producer has to claim the next slot on the buffer.  Then, when the producer has finished writing to the slot, it will call commit on the ProducerBarrier . So let's look at the first bi
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Dissecting the Disruptor: How do I read from the ring buffer?

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The next in the series of understanding the Disruptor pattern developed at LMAX . After the last post we all understand ring buffers and how awesome they are.  Unfortunately for you, I have not said anything about how to actually populate them or read from them when you're using the Disruptor. ConsumerBarriers and Consumers I'm going to approach this slightly backwards, because it's probably easier to understand in the long run.  Assuming that some magic has populated it: how do you read something from the ring buffer? (OK, I'm starting to regret using Paint/ Gimp .  Although it's an excellent excuse to purchase a graphics tablet if I do continue down this road.  Also UML gurus are probably cursing my name right now.) Your Consumer is the thread that wants to get something off the buffer.  It has access to a ConsumerBarrier , which is created by the RingBuffer and interacts with it on behalf of the Consumer .  While the ring buffer obviously needs a se
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