From Zero to main(): Bare metal C
In this technical retrospective (2023), @olalonde shares practical architectural lessons learned from running, scaling, or migrating production software under lean constraints.
Core Principles for Independent Builders:
Defaulting to simpler architectures (such as monolithic frameworks, SQLite, or managed VPS) prevents early engineering bankruptcy.
Evaluating true compute and egress costs reveals that high cloud bills can often be slashed by 80%+ through judicious re-platforming.
Code you write at 2 AM as a solo engineer must be easy to debug six months later without complex microservice dependencies.
Community Debate Themes:
HN engineers debated the tradeoffs between cloud convenience and raw server economics, database indexing strategies, and resisting premature architectural complexity.
CATEGORY Frugal Engineering →
HISTORICAL ERA Post-ZIRP & AI (2023–2026)
COMMUNITY SCORE ★ 5 points
TOTAL DISCUSSIONS 0 comments
Ahh the SAMD21G18. Of all the chips to show up on HN today. This chip I know not half as much as I'd like to and half as much I wish I didn't have to.
We ported a rarely heard of RTOS to this chip (TNEO), and one of the most difficult parts was running tickless with sleepable states. The difficulty (discovered only by blood, sweat, tears, wtf oscope moments, dumb luck, and a random comment found on some obscure forum, definitely not in the data sheets) was that accessing certain registers (in our case RTC.CNT) would cause the chip to go in to a different clock domain temporarily and suddenly take as much as 300 usecs to read. Just this line:
``` uint currentClock = RTC.CNT;
``` That's all it took. Whereas most store some register into some local variable took nanoseconds, this one took a long long time.
My experience in this world of embedded chips, is that many of the tutorials you read do not deal with power consumption really. They assume that you're playing with a dev board. Or that your application has copious amounts of power. But if you live in a battery powered world, your entire game lies around navigating between sleep and wake states on the chip.
Courtesy heads up for any hardware n00bs like myself who are buying the parts to work through this series hands-on: some of the required parts are hard to find. You should double-check that your replacement parts will work. https://news.ycombinator.com/item?id=33360830
Isn't that last part a bad assumption since it could be arbitrary values as well? Because people expecting a default zero value might be surprised otherwise.
New and soon to be published book on bare metal C by Steve Oualline (authors of several C programming books):
https://nostarch.com/bare-metal-c
Similarly interesting:
CppCon 2018: Matt Godbolt “The Bits Between the Bits: How We Get to main()”
https://www.youtube.com/watch?v=dOfucXtyEsU