alt Hacker NewsYeah the issue is that the pedagogy doesn’t make it clear how to bridge the “calculator” with the OS stuff. I had this issue when I was a kid. How does adding eventually make something draw on the screen? Of course, it doesn’t, you need some hardware or OS specific information
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But if this doesn't satisfy your curiosity, you might realize this is just pushing the magic blackbox/question mark a little further down the chain
How does the OS and the hardware draw on the screen, actually? All they have is also just calculator stuff, super basic primitives. You can't even do loops in hardware, or even real branches (hardware always "executes both sides" of a branch at once)
Anyways, if you keep digging long enough you eventually end up finding this XKCD https://xkcd.com/435/ =)
It wasn't until I read Petzold's CODE that this stuff, especially the role of the the motherboard bridging processing, memory and I/O and what an OS is for, that it started to click for me.