Chasing Seymour, Supercomputing And Punchcards

Book about the CDC-6600 architecture

Back in November last year I wrote about ‘The Supermen‘, the story of Seymour Cray and the birth of supercomputing and mused about my personal reasons to learn about this particular piece of computing history. Reading about something is one thing, getting hands-on experience with technology from the 1960s quite another. Not possible you say?

Continue reading Chasing Seymour, Supercomputing And Punchcards

NB-IoT From Theory To Practice

Waveshare/Simcom NB-IoT Module

Back in 2016 and 2017 I had quite a number of articles on NB-IoT, the Narrow Band Internet of Things technology that can run alongside LTE to connect things to the Internet over the cellular network. From being very power efficient to run over years on batteries to increased in-house coverage, the standard contains a lot of bells and whistles to address a wide variety of use cases. While I believe that ‘connecting things’ is the next big thing after mobilizing the Internet, it’s been very slow in the making, at least when it comes to cellular connectivity. I would have been quite keen to experiment with NB-IoT but up to now I didn’t come across devices and SIM cards that could be bought that would support it. Until a few days ago that was when I discovered an NB-IoT module for the Raspberry Pi on Amazon so it was finally time to go from theory to practice on the technology.

Continue reading NB-IoT From Theory To Practice

Booting With UEFI

The BIOS Boot Menu

One of the technology mysteries most people don’t really want to spend a second thought on is how the operating system of a PC is booted. When installing Linux next to Windows on the same disk, however, or when you plan to move a disk from one PC to another at some point, or when you want to restore a system image from a backup, it’s worth to understand at least the basics of the process to fix things in case something goes wrong. In a recent edition of the c’t magazine (see here, in German, article behind a paywall) there have been a number of great articles about the topic and here are my takeaways that will help me in the future.

Continue reading Booting With UEFI

5G Auctions – Let’s Look Back to 1989

GSM license award in December 1989

There is a lot of media attention in Germany on the upcoming spectrum auction for 5G that is scheduled for early 2019. Like in previous rounds, spectrum is awarded via an auction to the highest bidders. Someone recently asked me if spectrum has always been auctioned so I had a look in my archive to find some details from days long gone.

Continue reading 5G Auctions – Let’s Look Back to 1989

Javascript Debugging on the Tablet

Connection Establishment between Tablet and PC

Unknown to most people, web browsers such as Firefox have a sophisticated debugger built-in to look at everything from page load timings to HTTP header contents and Javascript debugging. For web developers this is a great help on the PC. Recently, I had to debug a web application that worked all right on the PC but wouldn’t quite work as intended when used on a tablet. So what’s the approach for debugging a web app on smartphones and tablets? I turns out that Firefox on Android on the PC have powerful ‘remote over Wifi’ debugging capabilities that are surprisingly simple to use.

Continue reading Javascript Debugging on the Tablet

Things That Moved Me in 2018 – Part 2

And off we go straight into part two of my summary of things that moved me in 2018!:

Raising My Shields – Year 5

Ever since the Snowden revelations in 2013 I’ve been moving more and more services I use into my own domain and made sure as much of my Internet traffic as possible is encrypted. In 2018, I’ve made a number of significant improvements. First and foremost, Nextcloud Talk has become available and I’ve been using it since its launch for end to end encrypted and self-hosted voice and video calling. While it still continues to evolve for a more ubiquitous use from mobile devices, I used it a lot for voice and video calling from PCs in 2018.

Another weak point in my communication infrastructure has been internal email. While I made sure communication encrypted between clients and the external server, emails were obviously unencrypted while on the external server. So this year I took some time to finally put an email server in place at home for family internal emails that contain things that really shouldn’t be stored outside our domain of influence.

Continue reading Things That Moved Me in 2018 – Part 2

Things That Moved Me In 2018

Another year is coming to an end again so it’s time once more to have a look at which things have moved me this year and how technology has moved forward, or not.

5G – 5G – 5G

If you visit this site every now and then you have probably noticed that 2018 has been the year I spent a significant amount of time going through the 3GPP 5G New Radio and 5G Core Network specification and have written more articles about it then I could possibly link in this post. Despite the flood of claims of 5G firsts and pseudo 5G network launches, the technology is still in the making. But that’s to be expected as 3GPP only released a first and very patchy version at the end of 2017. The people in 3GPP have taken everything apart from the radio to the core network and put it together again in a new fashion for fast and better future wireless connectivity that will keep us busy for years to come to put into practice. So here’s a link that will lead to all of my articles with ‘5G’ in it, from 2018 and other years. If you are interested if I already wrote about a specific topic, use the search box on the left.

Continue reading Things That Moved Me In 2018

5G EN-DC Option 3 – Call Flows

If you are interested in how a 5G EN-DC Option 3 connection is set-up between the mobile device and different components in the network the best but also the hardest way is to look up the procedures in a number of different 3GPP specifications. 3GPP TS 37.340 is a good starting point for EN-DC. Another interesting source that I have just discovered is over at On the page, there are a number of links to call flow diagrams that aggregate a lot of information from different 3GPP specs and to a blog post with some more details and a video at the end. Interesting stuff!