Many people in Hacklab community are working on interesting projects or have something cool that they would to share with others. To give a chance to spread the word we are having a Show and Tell session on Tuesday 16th September from 8pm at the Hacklab It will be pretty informal, each talk will be Read more about Show and Tell – Tuesday 16th September[…]

Arduino is a micro-controller platform designed for ease of use and learning. It allows the creation of electronically controlled projects, whether it be simple blinking lights, a robot or a music generator. This workshop is aimed at beginners. You don’t needs any previous electronics or programming knowledge or experience. Topics covered include: An introduction to Read more about Arduino for Beginners Workshop – Saturday 7th June[…]

On Saturday we had a visit from around a dozen members of The Software Society of Dundee, who are currently pondering upon setting up their own space. Ted, Gareth and Gandolf showed them round and talked a little about what we went through in setting up the lab. We’re planning an away team trip to Read more about Visit from The Software Society of Dundee[…]

my task

"connect 80k simultaneous clients, logging in and out at an overall rate of 50Hz, and requesting pages at an overall rate of 100Hz"

lets model a client as a random walk on a state graph (a Markov chain), where the action taken by a client is drawn from a distribution conditioned on the current action. (TL;DR we will bootstrap frequency estimates from this representation using eigenvectors)

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Missed out on our recent Arduino or soldering workshops? You’re in luck! In April, we’re running workshops as part of the Edinburgh International Science Festival. We have four different workshops in the Festival programme, each one running twice during the two-week Festival: Getting started with Arduino Arduino is an easy to use microcontroller platform designed for Read more about New workshops for the Science Festival![…]

Hacklab member Gary Martin has a new shiny gadget: an Ultimaker 2 3D printer. This Thursday from around 19:00 Gary will host an informal workshop to demo some of the software, print some widgets, and bring along his stash of test 3D prints for closer examination (some seen in the photo above). Gary has been Read more about Thursday 20th: 3D printing with the Ultimaker 2[…]

I am writing a static analyser for Firebase. My approach to precedence and brackets has always been, if in doubt, whack a bracket round it. Unfortunately when writing code generation tools my output ends up with more brackets than logic :s

Anyway, I was having trouble debugging my generated code, and it was impossible to reason why it wasn’t working what with all the brackets. So I kept with maximum bracket insertion in the 1st pass (a reliable strategy), but wrote a function for removing ALL redundant brackets from a Javascript expression post 1st pass (easier to read). It took a while to get right but I was very pleased with the brevity.

So the expression: (4 + 6) * 6 needs its brackets to operated correctly, but (((4) + (7) * 8) has a number of pointless brackets in it. There are some tricky cases like 5 / (7 * 6), which requires brackets despite * and / having equal precedence. To understand why 5 / (6 * 7) needs brackets you have to understand that when operators have equal precedence, by default, they associate to the left. Anyway the code to actually do this turned out to be super compact so I share it with you!

I used node-falafel which is an awesome package that allows in place source code rewrites during a bottom up parse. Woah! The function “simplify” takes an expression as a string, and returns a functionally equivalent expression but without the pointless brackets in it. Nice!

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With the 2014 Global Game Jam fast approaching I have been asked a few times by new participants what they should take with them, and how they should prepare. Wikipedia defines a game jam as “a gathering of game developers for the purpose of planning, designing, and creating one or more games within a short span of time“, they are a wonderful experience for anyone interested in game development. They are often suited to any level of experience, as participants can form themselves into teams with total strangers of compatible skill-sets. Often people will volunteer to take a role that they know little about, experiencing a new side of the development process or polishing rarely used skills.

The Global Game Jam is a yearly event, taking place simultaneously around the world with a single theme given out to all participants. The event itself lasts for 48 hours, a very long time to be awake and developing, but a very short time to put a project together with a team of people you may have never met before! This makes it quite an exciting challenge that deserves at least a little preparation and planning! To that end I’m going to give you a few ideas and tips from my own experience. Ultimately a game jam is about being yourself, creating something, and having fun. There is no right and wrong, and it’s not a competition! Your experiences will vary, and my suggestions are only a rough guide. (Please note that none of the links in this post are affiliate links!)

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Firesafe has just been developed and uploaded to github

Firesafe is a technology to enforce data integrity, and enable complex transactions, on Firebase.

Firesafe compiles hierarchical state machines (HSM) definitions into Firebase security rules. The Firesafe HSM language is expressive, and a super set of the Firebase security language. Adding consistent, concurrent and fail safe protocols to Firebase is now a whole lot simpler (e.g. cross-tree transactions).

Firebase is already the future of databases, offering scalable low latency database-as-a-servie. Firesafe, compliments this amazing technology with an expressive syntax to get the most out of its security model. (Firesafe is not endorsed by Firebase)

Motivation

In multiplayer apps/games, people cheat. It’s a loss of direct sales, AND the free loaders also diminish the fun for everyone else. Multiplayer games are webscale, which means the old solutions to data integrity and transactions don’t work (e.g. SQL).

Firebase solved one problem of the cost of providing low latency persistent data storage to mobile and desktop games. It’s the first scalable NoSQL hosted solution that didn’t suck. It also provided an unorthodox security and transactions abstraction. Turns out that abstraction has enough purchase to do some really cool things not possible in many NoSQL environments. Unfortunately, properly configuring the security layer is extremely verbose and error prone. Firesafe makes it easy.

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I’ve been interested for a while in cellular automata, pattern generating mathematical formulae such as Rule 90. 

There are many of these rules, each generating different behaviour. Each rule generates the content of cells in a column based on the cells in the preceding column, and are each based upon given starting conditions. 

These are the rules for Rule 90: