Edvin Kalda

Systems engineer. Tartu, Estonia. Working alone since March 2023.

I work on the quiet half of operations: why a machine that is doing nothing draws 24 W instead of 18, why a scheduler picks a cold core at the worst moment, and how long a processor really stays in its deepest idle state once you stop poking it.

Eleven of those years were spent on somebody else’s payroll - a regional telecom first, then an outsourcing development shop, then two years looking after about nine hundred machines for a hosting company. Since the spring of 2023 I take three or four jobs a year on my own, which is enough to live on in this city and leaves time to finish a measurement properly.

Nothing on this site is for sale. The notes are the things I managed to measure, including the ones where the answer turned out to be «no difference, stop here». The reading page lists subjects rather than titles, because I keep lending books out and forgetting which edition came back.

Lately

• 2026-10-06 - a note on what an idle login costs, and why I take every reading logged out.
• 2026-09-18 - a note on hunting down 118 wakeups a second on a machine that was supposedly asleep.
• 2026-10-02 - rewrote the now page; the old one still claimed I was learning to solder.
• 2026-07 – 2026-08 - six weeks of power measurement on a fourteen-node render cluster. The client asked me not to write it up, so there is nothing here about it.

If you came here for something

The notes have the tables and the methods. Work says what I did before and what a job with me looks like, including the parts I refuse. If you want to ask something, write; I read mail twice a day and answer within three.

This page is hand-written markup and one stylesheet. There are no images and no fonts loaded from elsewhere, and the only script is the optional filter on the notes page - partly taste, mostly because I like pages that open on a bad hotel connection.