Call Center Simulation – Influence of Call Durations Distribution on Statistical Results

Recently I’ve refurbished an old project of mine, the Call Center Simulator CCsim ( It was a lot of fun to develop this heavy multithreading app. One main reason for me at the very beginning was to see how big the influence of the actual shape of distributions (e.g. for the call duration) besides the mean value is on the results. Now we do have this tool and we can play around a little bit.


Performance of a Heavy Multithreading App on Apple Silicon

I couldn’t resist. Now, the new Apple Silicon macs are out and I had to buy a new Mac mini to test my applications on the new architecture (and the new macOS 11.0). Recently I released my refurbished project, the call center simulator CCsim ( It is heavily relying on multithreading and I was eager to see what it is doing on M1-equipped macs. Weiterlesen

Display portrait and landscape format picture in equal size using a video projector

Do you also feel that this is the big disadvantage of modern picture projection compared to the old-fashioned slides: portrait format is really handicaped because you have two big black bars on the left and right hand sides. Video projectors have an aspect ratio of 4:3 or even 16:9 compared to the squared display size of old slide projectors. Weiterlesen

Performance of Swift vs. Objective-C and the Debugger

Recently I have migrated an old project of mine from Objective-C to Swift. It was not that difficult and it worked out fine, and I was eager to see how the performance of the migrated system would turn out. How big was my disappointment when I saw that the Swift version of my system was at least a factor of 10 slower than the Objective-C version with unchanged functionality. That can’t be true, I thought and debugged at little bit.


Trusted Domains in NextCloud

Recently I installed NextCloud as a common storage for our choir on some hosted server. Everything worked fine beside the usual little problems during installation procedures. Also my fellow choir members were quite happy with new system but a few of them were complaining that they could not login to the NextCloud. The error message they got was something like „Access through untrusted domain“. Well, I could not imagine what happened here. The SSL certificate was correctly installed and valid. And why did it happen only to a few of them and not all? Weiterlesen