https://cpu.land/ explains “what exactly happens when you run a program on your computer?”. I have been learning about microcontrollers and embedded systems recently and this site came up.
By good fortune it assumed a level that matches my previous understanding of CPUs and computers and operating systems. A lot of what I was reading what new but I could understand it readily. The style is friendly, not overfamiliar, readable; I kept going back over a few days until I’d read everything – the whole site. There are occasional snippets of library code and kernel code that illustrate the point without oversimplifying and without being intimidating – I think this is a hard balance to strike. Some well-chosen asides brought the subject to life even more. I’m grateful to the authors for publishing such a great resource.