A blog of tech, engineering and mathematics
If you work with tech, there’s a good chance you’ve come across some of the following statistical tools: Averages Standard deviations t-tests Least-squares line of best fit These are the most common tools in a kit that’s typically taught in undergraduate statistics classes and widely used in the outside world. However, this toolkit just isn’t that effective in most IT applications (such as…
GNU stow is an underrated tool. Generically, it helps maintain a unified tree of files that come from different sources. More concretely, I use a bunch of software (D compilers, various tools) that I install manually instead of through my system’s package manager (for various reasons). stow makes that maintainable by letting me cleanly add/remove packages and switch between versions. Here’s how…
I’ve been self-employed for most of my career. Sometimes I talk to other people who are interested in leaving a full-time job to do some kind of contracting or service business. By far, the most common newbie mistake that we all seem to make is in pricing ourselves. Take this useful blog post that breaks down employee income vs freelancer income in the US . It estimates that you need $140k revenue…
A great thing about modern app development is that there are cloud providers to worry about things like hardware failures or how to set up RAID. Decent cloud providers are extremely unlikely to lose your app’s data, so sometimes I get asked what backups are really for these days. Here are some real-world stories that show exactly what.
This started with a consulting snafu: Government organisation A got government organisation B to develop a web application. Government organisation B subcontracted part of the work to somebody. Hosting and maintenance of the project was later contracted out to a private-sector company C. Company C discovered that the subcontracted somebody (who was long gone) had built a custom Docker image and…
Some work (like programming) takes a lot of concentration, and I use noise-cancelling headphones to help me work productively in silence. But for other work (like doing business paperwork), I prefer to have quiet music in the background to help me stay focussed. Quiet background music is good for meditation or dozing, too. If you can’t fall asleep or completely clear your mind, zoning out to some…
Code generators can be useful tools. I sometimes use the command line version of Jinja2 to generate highly redundant config files and other text files, but it’s feature-limited for transforming data. Obviously the author of Jinja2 thinks differently, but I wanted something like list comprehensions or D’s composable range algorithms. I decided to make a tool that’s like Jinja2, but lets me generate…
I’ve written a D implementation of the Project Woothee multi-language HTTP user agent parser . Here are some notes about what it’s useful for, and a few things special about the D implementation.
Warning: I don’t think the stuff in this post has any direct practical application by itself (unless you’re a nuclear war survivor and need to reconstruct maths from scratch or something). Sometimes I like to go back to basics, though. Here’s a look at π \pi and areas of curved shapes without any calculus or transcendental functions.
If you do any server administration work, you’ll have worked with log files. And if your servers need to be reliable, you’ll know that log files are common source of problems, especially when you need to rotate or ship them (which is practically always). In particular, moving files around causes race conditions. Thankfully, there are better ways. With named pipes, you can have a simple and robust…
Because D was originally created by a C++ compiler writer, Walter Bright, it’s an easy language for C and C++ programmers to learn , but there are little differences in the way declarations work. I learned them piecemeal in different places, but I’m going to dump a bunch in this one post.
About five years ago now, I handed in my Google employee badge and walked out of the Sydney Google office to start a new life of self-employment. I figured I should write up this story because I got a lot out of reading Michael Lynch’s . As you can see, it’s still taken me a couple of years to get around to writing this post, but I finally told myself that if I don’t write it for the fifth…