There will always be many gaps in peoples knowledge. You start with what you need to understand, and typically dive deeper only when it is necessary. Where it starts to be a problem in my mind is when people have no curiosity about what’s going on underneath, or even worse, start to get superstitious about avoiding holes in the abstraction without the willingness to dig a little and find out why.

I mean you can always make things slower. There are lots of non-optimizing or low optimizing compilers that are _MUCH_ faster than this. TCC is probably the most famous example, but hardly the only alternative C compiler with performance somewhere between -O1 and -O2 in GCC. By comparison as I understand it, CCC has performance worse than -O0 which is honestly a bit surprising to me, since -O0 should not be a hard to achieve target. As I understand it, at -O0 C is basically just macro expanding into assembly with a bit of order of operations thrown in. I don't believe it even does register allocation.

That would be true of one using a libc, but in a boot sector, you only have the bios, so the atoi being referenced is the one defined in c near the beginning of the article

The “fancy jump” is the branch instruction. As far as I know all ISAs have them. Even rv32i which is famously minimal has several branch instructions in addition to two forms of unconditional jump. Branches are typically used to construct if / for / while as well as && and || (because of short circuiting) and ternary (although some architectures may have special instructions for that that may or may not be faster than branches depending on the exact model). Without it you would have to use computed goto with a destination address computed without conditional execution using constant time techniques.

In comparison to datacenters in space yes. Solar roofs are already a profitable business, just not likely to be high growth. Datacenters in space are unlikely to ever make financial sense, and even if they did, they are very unlikely to show high growth due to continuing ongoing high capital expenses inherent in the model.