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Quis custodiet ipsos custodes?
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Hi there!

I'm Remy, a developer with a focus on C, C++, linux and embedded systems.

I currently work for De Jong DUKE were I develop software for an embedded platform that powers coffee machines. This is a C++, C and Qt stack running on Yocto linux and Nucleus RTOS. It controls hardware, runs the UI and has a few utilities for IoT connectivity and configuration. Technology is mostly C++ but includes Microsoft Visual C++, Flash, Qt and ARM kernel drivers.

I've been a Linux and UNIX sysadmin for over 10 years.

To read more or get in touch, click here.

This is my personal website, these articles do not reflect or are based on work, opinions or policies of any of my (previous) employers. Any resemblance to reality is pure coincidence.

Latest Items

Semi-accurate live stream viewer count (hls/rtmp/restreamer) on the command line

25-11-2020 | Remy van Elst

Due to all the working-from-home in the past few months I had to setup a live stream. At first the stream went directly to YouTube, but after they've screwed up multiple times, we decided to not be dependent on them. Using restreamer, a piece of open source software to live stream both to your own server and to another (YouTube) at the same time, we have more control over the stream and are not surprised by YouTube doing stupid stuff unannounced. Restreamer provides a simple web player that works on all major platforms and streams to YouTube, but one thing it lacks is a live viewer count. That's a hard problem to solve correctly and accurately, in this article I'll show you how to do it semi-accurately via multiple ways, including live graphs. This article contains a rant on YouTube breaking stuff and the commands used to get a live viewer count.


Installing OpenVMS 8.4 Alpha inside AXPbox on Debian 10 / Ubuntu 20.04 with networking

Published: 04-11-2020 | Last update: 08-11-2020 | Author: Remy van Elst

In my previous article I announced the fork of the `es40` emulator to `AXPbox` by Tomáš including bug fixes and rework allowing it to install OpenVMS 8.4 without problems. Since then I've contributed a few patches and doc updates, now NetBSD boots as well (the patches for netbsd were from other es40 forks). I've also looked into getting networking setup, since that is a bit of a tedious process due to pcap and linux, pcap being used for network emulation. SIMH (among others, a great VAX emulator) suffers from the same problems with networking. This guide will show you how to install AXPbox and get OpenVMS 8.4 ready and running with networking inside AXPbox. It's a rather long guide with a lot of information and output.


std::accumulate in C++

Published: 23-10-2019 | Last update: 07-11-2020 | Author: Remy van Elst

I'm using codewars to practice my development skills. Today I found out about the std::accumulate method in C++ while doing an exercise there. I'm sharing it here because I never heard of it before. It is the numeric header, and it also accepts a custom binary function to apply instead of operator+. This snippet shows some examples including a lambda operator and the for loop you would use otherwise.


Get number of incoming connections on specific port with ss

Published: 25-08-2020 | Last update: 07-11-2020 | Author: Remy van Elst

Recently I had to write a few monitoring plugins, one of which was a count of incoming connections to a specific network port. In the past I would have used netstat and a combination of grep and wc filter out only specific ports and established connections, but nowdays netstat is replaced by ss on ubuntu. ss has options to filter directly on all sorts of stuff, like state, ports, protocol, making the command I use more readable and use less pipes.


Exciting OpenVMS Alpha Emulation news, es40 has been forked to Axpbox (and works!)

28-10-2020 | Remy van Elst

Back in 2018 I was playing around with OpenVMS a lot, as it continues on the legacy of the PDP-8 and PDP-11. OpenVMS 7.3 on the VAX emulated via SIMH runs perfectly, OpenVMS 8.4 for Alpha was kind of a disaster, or, the es40 emulator was. Real hardware is available via IslandCo, but shipping to the Netherlands is horribly expensive. The only options back then for emulation of Alpha were FreeAXP or AlphaVM, both paid, closed sourced products with watered down free versions. Nothing wrong with that, it enables us to play around, and now that OpenVMS is in the hands of VMS Software with an x86 port coming along we may hope for a bright future ahead for OpenVMS. VSI currently provides a hobbyist version, but it's a FreeAXP bundle for Windows only. Recently I got an email from Tomáš regarding his fork of the es40 emulator, axpbox. This short post is intended to give this emulator more visibility and exposure, since I find this to be amazingly cool and exciting. It lists the bugs fixed and new features, which allow OpenVMS 8.3 and 8.4 to install perfectly.


I enforced the AGPL on my code, here's how it went

20-10-2020 | Remy van Elst

Five years ago I made a website that allowed you to put in a few domains and get an email when the SSL certificate was about to expire. No ads, no fuss, just an easy way for people to keep tabs on their sites without setting up their own monitoring like Nagios. As with all of my software, I released it under the AGPL due to it being web based software. Recently I found a company that hosted certificatemonitor, with some modifications (branding and a dutch tanslation), without any reference to its origin, no source code provided and no mention of the license. In this article I'll talk about what I did to enforce the license and how it went. TL;DR, not as expected. The company responded timely and friendly, but did a half assed attempt (added a link to my site with 'Inspired By Remy' as the text), then after my complaints, took down the entire site.


What does cost to run?

27-09-2020 | Remy van Elst

Inspired by recent articles from Kev Quirk, Horst Gutmann and Jan-Lukas where they do a cost breakdown of their sites, I decided to do one as well. Kev is around USD 30, Horst is around USD 13 and Jan-Lukas is around 5 USD. Their breakdowns are interesting, from specific wordpress plugins to CDN or DNS costs. I don't have those, but I do have a multitude of small servers running this site, which add up to around USD 20, adding up two domain names gives me around USD 22 per month. It could be a lot cheaper, I only need one server for the gigantuous amounts of static HTML this site consists of, but I do have around 10.000 unique visitors each day, so having redundancy is nice. If I would go all cheap, this site would cost me no more than 2 USD a month including the domain name, but that would take the fun out of it. This article features a list of similar, how much does my site cost articles and a cost breakdown of this site.


Tiny Tiny RSS vs Miniflux

26-09-2020 | Remy van Elst

I'm an heavy user of RSS feeds, having over 1500 feeds I follow. Without a decent feed reader that setup wouldn't work. For over eight years now I've been an happy user of Tiny Tiny RSS, a web based feed reader. But, recently I found out about 'miniflux', also a web based RSS reader. In this article I'll compare the two for my use cases, mostly mobile usage. TD;DR, I've switched to Miniflux, due to it being more suited for mobile usage, less ajax heavy, easier to subscribe to feeds and a more pleasant reading layout.


Store multiple types in a single std::map in C++ with std::any, just like a python dict

23-09-2020 | Remy van Elst

In C++, everything has a type. When declaring a function you specify the return type and for each parameter you specify what type it is, just as for regular variables. Templates aside (those still have a type), you almost always know what type of data you're working with. There is the 'auto' keyword, which can save you a lot of typing and duplicate code, but fundamentally you're still working with types. Since C++ 17 you can use 'std::any' to store anything, without knowing the type. This is awesome for some tasks, and horrific for most use cases. In this article I'll show an example of a 'std::map' with 'std::any', that behaves like a python 'dict', it's able to store multiple different types in the same container.


CookieNumberPrinter, incremental / idle game style numbers in C++

12-09-2020 | Remy van Elst

To level up my software development skills, I'm programming a command line game in my spare time. It is a clone of the famous cookieclicker game by ortiel. A clone of a game is simple enough to get up and running fairly quickly, but also extensible enough when needed. How do you store huge score numbers when they don't fit in a long long? How do you write a game loop, how to use threads to handle user input? Saving a game (how to design a proper save format)? Also a great way to learn about project organization, software architecture and to try out design patterns. As the game is a clone of CookieCliker, which itself is an incremental game, I had to figure out how to work with large numbers. Since this is not a university math project, I allowed myself the luxury of using Boosts Multiprecision. The library handles the large numbers, including caluclation and operations with such a number. I did want to print the numbers in Idle Style, where large numbers are displayed with a suffix, like '1 million' instead of '1000000' and so on. This 'C++' class can be used to print Boost's 'cpp_dec_float' numbers in incremental style. It's just one header.


Get all SSH public keys from gitlab

26-08-2020 | Remy van Elst

This small snippet gets all the SSH keys from a gitlab instance. You need to be an administrator, then you can query all keys at once using the API. On the web frontend you can only see the keys per user, not all at once in an overview.


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