Git Under the Hood
While I’m not a programmer per se, I do use git almost daily and find it a great tool for source control and versioning of plain text files. But I don’t think there can be any doubt that it is not the easiest tool to use. But despite its unintuitive user interface, under the hood git is quite simple and elegant. I believe that if you can understand the fundamental constructs git uses to store, track, and manage files, then the using git becomes a lot easier.
Read more…A Noisy Wind Tunnel
I raced bikes as a junior and came back to it after a twenty year hiatus. One of the biggest contrasts I’ve seen in the sport is the proliferation of bike sensors. All I used to have ‘back in the day’ was a simple computer with velocity and cadence. Now I’ve got that, plus position via GPS, power, heart rate, pedal smoothness and balance, all collected and displayed on my phone.
Read more…A Tale Of Two Optimisations
A couple of months ago I wrote a toy program called whitespacer. Ever since, I’ve had this gnawing feeling that I could have done it better; that it could have been written in a more performant manner. In this article I’ll take you through a couple of different ideas I came up with. We’ll profile and visualise their different performances and stumble upon some surprising behaviour. We’ll use this as an excuse to take a deeper dive into their behaviour at the CPU level and gain a better understanding about the
Read more…perfperformance analysis tool and branch prediction.Bandwidth Seasonal Decomposition
Over the past few months I’ve been studying time series data and modelling using Rob Hyndman’s fantastic Forecasting: Principles and Practice textbook. My area of expertise is in networking, and a significant amount of operational the data that we deal with fits into the category of time series data. It could be throughput through a router, sessions on a firewall, or the counts of HTTP response codes from a content delivery network.
Read more…Whitespacer
A few weeks ago I was analysing some packet captures and thanking the RFC gods that HTTP - and many other protocols - use ASCII/UTF-8 rather than packing everything into binary.
Read more…What the #!
Working with computers you take a lot for granted. You assume your press of the keyboard will bubble up through the kernel to your terminal, your HTTP request will remain intact after travelling halfway across the globe, and that your stream of a cat video will be decoded and rendered on your screen. Taking these things for granted isn’t a negative, in fact quite the opposite. The countless abstractions and indirections that hide the internal details of a computer are the reason that people - computer science degree or not - can use them in some shape or form.
Read more…A Bit on the Nose
I’ve never been particularly interested in horse racing, but I married into a family that loves it. Each in-law has their own ideas and combinations of factors that lead them to bet on a particular horse. It could be it form, barrier position, track condition, trainer, jockey, and many others.
Read more…AFL Bets - Analysing the Halftime Payout
If you’ve watched AFL over the past few years, you would have noticed betting companies spruiking a cornucopia of betting options. In fact it would be hard for you not to notice, given the way they yell at you down the television screen.
Read more…Simulating Snakes and Ladders
For the past couple of months my family and I - like the rest of the world - have been in isolation due to the coronavirus. My eldest son Ned is 5 years old and is interested in games and puzzles at moment, so these have been a key tool in reducing the boredom of lockdown.
Read more…Packet Analysis with R (Part 1)
As a network security consultant I’ve spent a my fair share of time trawling through packet captures, looking for that clue or piece of evidence I hope will lead me to the root cause of a problem. Wireshark is the the tool par excellence for interpreting and investigating packet captures, however I’ve always found that it’s best suited to bottom-up rather than top-down analysis. Opening a packet capture you’re bombarded with information, the minutiae from each packet instantly available. This is perfect if you know what you’re looking for and can filter out the noise to concentrate on your problem. But if you don’t have a clear view of what’s in the capture, or where the problem may lie, taking a step back and removing yourself from the details in Wireshark can be difficult.
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