Author: george georgovassilis

A differential amplifier built with a current mirror

I've wondered for a long time how differential amplifiers are actually realised on the transistor level. Not having received a formal electronics engineering education nor being part of an assorted online community, that question lingered for quite a while unanswered - until yesterday. The ideal differential amplifier The differential amplifier (DA) is an electronic element … Continue reading A differential amplifier built with a current mirror

docker-proxy port in use

Quick one: you're starting a container through docker-compose and it says a port is in use. You "netstat -plutn" it and find out, that port is in use by docker-proxy. Github user rdavaillaud knows what's going on: stop dockerremove all internal docker network: rm /var/lib/docker/network/files/start docker

parchive: protecting backups against data corruption

As time goes by, my [place appropriate interval] backups may not grow much, but the size of my entire data archive exceeds the largest available hard disks (don't ask). Taking into account correctness guarantees by hard disk manufacturers, transmission errors over the network and who knows what else, I don't feel confident that I'll flip … Continue reading parchive: protecting backups against data corruption

Book of dark arts: storing data in the view

Pentagram, source Wikipedia. Towards the end of the year I'll indulge in the dark arts, join the goblins and leave my white architect hat under the Christmas tree where it belongs. I'm helping a friend (a technically minded, non-programmer) write his first mobile app . We wanted to keep everything simple: use technologies which can … Continue reading Book of dark arts: storing data in the view

Thunderbird forgetting passwords

After a simultaneous Thunderbird upgrade and profile migration from Windows to Linux the mail program permanently forgets passwords.       The setting: Thunderbird 52 on Windows Back up profile Restore profile to Thunderbird 60 on Linux Observe that all passwords to all accounts are lost even if entered again This seems to be some … Continue reading Thunderbird forgetting passwords