2025-02-14 | #conference #free software #meetup
In February 2025 I attended FOSDEM in Brussels, Belgium for the first time. During two days, 1052 events/talks were held with 933 speakers. As you can imagine, I only attended a fraction of the sessions. As part of FOSDEM, many free software projects have booths, and I also spent time working around in the booth areas to get an impression of the diversity of the free software community today.
2023-07-29 | #chemical kinetics #javascript #numerical analysis #ODEs #oscillating reaction
As a graduate student I implemented kc to simulate oscillating chemical reactions, and in collaboration with Keld Nielsen, I implemented numerical methods to solve ordinary differential equations (ODEs).
The Brusselator is a fine example of an oscillating chemical reaction, and for most values of the parameters the behavior is pretty fine (meaning that you don’t see very advanced numerical methods to solve it).
I recently noticed that functionality to solve ODEs has been added to Mathjs. To me that is a major development, and it make Mathjs an interesting library to work with. In order to try out the new functionality, I have simulated the Brusselator in JavaScript (using node.js). My little script brussel.js is:
2023-01-05
My old blog has been inactive for many years. And for the last five-six years, I haven’t published any articles in computer magazines. It is time to revive my writing habits. This is a new beginning for Kneth’s Korner.
As free and open source software is close to my heart, Hugo seems to be a logical choice.
2018-10-27 | #git #github #vscode
Visual Studio Code has since it first public release in 2015 increased fast in popularity. Being a cross-platform editor and released as open source software, many software developers have downloaded it. The fact that Microsoft is behind Visual Studio Code means that programming languages like TypeScript, C#, and C++ are well supported.
Git has become the de facto standard for version control systems. In particular Git providers like Gitlab, Bitbucket, and Github have made it easy for software developers to set up Git repositories. Many developers are using Git directly from the command-line, but there exist also a good portion of graphical Git clients. Today, any code editor and any integrated development environment (IDE) must have some kind of Git support.
2017-05-04 | #Android #bug #Realm
This blog post was first published as When memmove fails
It was late October last year, and as we began preparations for Realmstravaganza — our annual all-hands gathering in Copenhagen — we started receiving bug reports with some serious native crashes. No one could have guessed just how deep of a rabbit hole we’d have to go down to find a fix. Before we were done, we’d be neck deep in compiler-level optimizations of fundamental C functions, looking for a smoking gun that wouldn’t even set off our unit tests.
2014-12-29 | #javascript #web
I picked up the book - not because I’m working on WebRTC or related stuff but simply to get an idea of what this new technology is all about. It’s a lengthly book, and the author seems to know every trick of the trade. After finishing the book, I feel that I have a better understanding of what WebRTC (and SIP and PSTN) works - at least on the high level.
2014-12-04 | #javascript #web
Promises are an old pattern in concurrent programming. In the computer science literature, promises date back to the papers by Friendman and Wise from mid 1970s. Many programming languages have promise - and futures as in Java are a similar idea. A promise is a variable or an object which value is initially unknown and is the result of another task. Modern JavaScript development is highly asynchronous by design: the UI (in the web browser) is updated by calls to the backend using HTTP requests.
2013-12-10 | #COBOL #free software #OpenCOBOL
Yesterday, Grace Hopper would have turn 107 years old. She was one of the first computer scientists. She worked on compilers but she is probably best known for her development of COBOL. COBOL is one of the first high-level programming languages (FORTRAN is the other one). Back in the 1950s, computers were used as calculators, but COBOL and Grace Hopper shown us that computers can be used for much more that simple calculations. Today, COBOL is still wildly used.
2013-11-10 | #big data #free software #map/reduce
Quinton Anderson has written a book on the analysis platform Storm and published it at Packt. I have worked a little with Hadoop in the last couple of years, and it is only natural to take a look at the other big data processing platform. Hadoop is a batch processing platform, and Storm is for real-time processing and analysis of data. That means the two projects are not direct competitors, and they might complement each other.
2013-07-05 | #javascript #web
Recently, Packt Publishing published a book by N. Bhava on ExtJS. It’s a fairly short book, about 60 pages long. The idea is to get you started with ExtJS. If you don’t know what ExtJS, it is a framework to develop the front-end of web applications. Today, users except web applications to behave must like desktop applications, and a typical web developer is much more like a GUI programmer just a few years ago. In order to get started with ExtJS, the book is an excellent introduction. By reading the book, it quickly becomes obvious that today’s web developers just have a great deal of knowledge of JavaScript, object-oriented programming, HTML and CSS. JavaScript is a class-less object-oriented programming language. But ExtJS is based on the notion of classes, and they are somehow emulated by plain JavaScript. The author does not go into details - probably due to the limited length of the book. A book of less than 60 pages cannot scratch the surface no matter how great the author is. Indeed, the book is quite well written, and the flow of the book is fine. But I must be honest, I have tried ExtJS ever before, and the book is too short for my taste. I do like the cook-book like steps in how to install ExtJS. And I like the usage of the browsers’ debugger to inspect code and DOM. The proof-reading of the book could be better. On page 9, the different edition of ExtJS is mentioned twice, and the example of page 35 has an extra </tpl> tag. If you have another web framework (jQuery UI, YUI, etc.), you will find the book useful. It will give you a clear idea of what ExtJS is all about in a short time. The author emphases early that the strength of ExtJS is it’s components. The major components (layout, containers, data, templates, and forms) are discussed. In particular, the layout and data components are nicely explained. You can find the book here.
