Recent content on Greg Foletta - Bits and Blobs
Update: this post was discussed on Hacker News I completed a Computer Science degree at uni, and bundled a lot of maths subjects in as electives: partial differential equations, vector calculus, discrete maths, linear algebra. For some reason however I always avoided statistics subjects. Maybe there’s a story to be told about a young person finding uncertainty uncomfortable, because twenty years…
In this article we’re going to be taking a look at the forecast accuracy of Australia’s Bureau of Metorology (BOM), but before starting a quick preface. I had trepidation writing this article, and it almost didn’t get off the ground. I’m not a meteorologist, and I’m also a data science dilettante. Wading into this particular field without foundational knowledge felt very arrogant, and to be frank…
Last week I needed to pull some data from a website. I was building out a data pipeline to generate the end-of-season awards for Little Athletics, but I ran into a problem. Like dependable friend, R came to the rescue with a simple, elegant solution. This post is a ‘byte-size’ ode to this dependable friend. Beauty and Terseness I’ll get to the challenge I ran into shortly, but first we’ll take a…
Update: This article was discussed on Hackernews Much has been written and a lot of analysis performed on the global BGP table over the years, a significant portion by the inimitable Geoff Huston . However this often focuses on is long term trends, like the growth of the routing table or the adoption of IPv6 , dealing with time frames of of months or years. I was more interested in what was…
Most of the posts on this site tend to be long form, a result of me finding it hard to leave stones unturned. This leads to big gaps between posts; in fact the the radio silence over the past nine months is because I’ve had two in draft form and haven’t been able to get them over the line. As an antidote to this I’ve put together something a little more bite-size. In this post…
Last month my car, a Toyota Kluger, was hit while parked in front of my house. Luckily no one was injured and while annoying, the person had insurance. The insurance company came back and determined that the car had been written off and I would be paid out the market value of the car. The question in my mind was ‘what is the market value?’ How could I keep the insurance company honest and make…
My friend Jen is writing a thesis and recently reached out to me to see if I could help. She had an upcoming presentation up wanted to add some visualisation to it to better tell the story. I jumped at the opportunity as it was an opportunity to familiarise myself with an area I hadn’t previously explored: geospatial data. In this short article I’ll take you through the creation of the…
Before we start a note: this post is a sidebar for another article I’m currently writing. There aren’t any grand conclusions or deep insights, it’s more exploratory. Whilst writing an article on memory allocations, I needed a way to map a one-dimensional number (the memory location) on to two-dimensional space. By doing this I could visualise where in memory these allocation were…
There’s a few different pictures making their way around social media showing a complicated definite integral, and asking guests to evaluate it to get the password for free WiFi. Here’s an example: I loved calculus back at uni, but uni was a fair while ago now and I’m more than a little dusty. I briefly attempted integrating the equation, looking up some terms I could remember…
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…
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…
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…
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…
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. I then started thinking how confusing it would be to look at a packet capture and only see whitespace in the conversation. And thus whitespacer was born: a utility to encode messages into pure, soft, clean whitespace. How…
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…
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. After being drawn into conversations about their preferred selection methods, I wanted come at the…
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. One of the value adds these companies advertise is the ‘goal up at halftime’ payout. The terms are that if you have a head-to-head bet on the…
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. Snakes and ladders is one of the games that’s caught his attenton. While sitting on the floor and playing a game for the…
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.…