Castlerock

About

My name is Johan Liseborn and I have been working with software development since 1989, when I joined Ericsson in Bollmora (full CV). After a few years of developing PBXes in Plex-M I went to study computer science in Linköping. During that time, the internet became a thing, and since then, most of what I have been working on has been internet related.

In 1999 I co-founded Hotsip, where we built voice, video, and chat applications and infrastructure based on SIP. Hotsip got acquired by Oracle in 2006, and I spent a few years there. After that I co-founded a company offering mobile based task management for small businesses, but that never took off. I spent a few years working in the financial industry, first with TriOptima, and then briefly with Klarna.

In 2010 I joined Glactic to work on a web based dating service including real-time voice and video speed dating. The system was pretty cool, including a real-time matching engine based on Solr, and a real-time voice and video exchange engine built in Erlang, but once again, the service never took off.

In late 2011 I became employee #1 and CTO at Magine TV, where I was part of designing and building, from the ground, a real-time transcoding and streaming system for live, linear TV. I left Magine at the beginning of 2015, to found Castlerock and work on new, exciting projects.

I have learned that I like startups, and I like to be part of solving new problems and creating new systems from scratch.

Through the years, I have been working with many different things, from being a junior programmer to being a manager, a CTO, a board member, and a chairman of the board. I have found that what I like most is to work in startups, with a bright team, solving new problems, and building systems from scratch.

If you think that there is something I could help out with, please do not hesitate to drop me a mail.

My history in computing

I started out learning programming on my own in the early 80s. The first computer I used was a friends ZX81. I then got a VIC-20, followed by a C64. I started out programming in Basic on the ZX81 and the two Commodore machines. I also started learning 6502 assembler on the VIC-20.

In ‘84 or ‘85 I got a Sinclair QL, which was a really cool machine. It had a basic interpreter that was really easy, to extend with your own commands (in assembler), and it had a 68008 CPU, which meant I could start playing around with 68k assembly. It also had a pretty neat storage system, consisting of two “microdrives” with infinite loop tape cartridges. The only thing that sucked was the graphics, so it was no-good for gaming.

In ‘86 or ‘87 I got an Atari 1040ST, and a few years later I had a brief stint with an Atari TT. Sometime in the mid 80s, I don’t remember exactly when, I read an interview with Richard M. Stallman in a Swedish computer magazine. This was my first real exposure to free software. I found out that there was quite a lot of free software available for the Atari, and I started downloading and playing with all kinds of different free software packages, including Lisp and Scheme.

Sometime during ‘89 or ‘90 I got my first Sun workstation at work (this was at Ericsson; before that it had all been IBM mainframes at work), and I started learning Unix.

I got my first regular PC, a 486, sometime in the early 90s, probably in ‘92. I ran windows for a while, I tried OS/2 (it was handed out for free at my university and it was completely useless on that machine), and then switched to GNU/Linux, probably late ‘92 or early ‘93.

In December ‘99 I got hold of OpenBSD 2.6 and fell in love with the OS and the approach of the project. The focus, the attention to detail, and the dedication to the project goals, as well as the somewhat brusk, no-nonse and to-the-point way of communication (that some people perceive as rude) are all things I appreciate. For a few years, I ran OpenBSD as my primary operating system, on a number of IBM ThinkPads.

Since the mid 90s I have had a whole bunch of machines, mostly laptops, and mostly IBM ThinkPads (and later Lenovos). I switched to Apple machines (I know, I know) sometime in the mid 00s, the first one was a 12” PowerBook. I have always been fond of small laptops, favoring portability rather than raw performance. This also goes well with my thought that most software is bloated, and that we in general should be able to get by with smaller, cheaper machines.

Since September 2015 I run GNU/Linux on my machines, and since October 2017 my main machine is a Lenovo ThinkPad X270 with an Intel Core i7-7500U CPU, 16GB RAM, 512GB SSD, and a US keyboard (because that is more convenient for programming).