Justine Tunney - Redbean and the Actually Portable Executable (Speakeasy JS, May 2021) - Despite the channel, this is about a C executable that "runs anywhere", including from boot

Video is nearly 3 years old now, but I think it's worth watching. Her presentation starts at around 2:30.

Basically, she explains how Redbean, a tiny (~450kb) and very fast C http server, works and how the same executable can be used to deploy it on most operating systems (she starts explaining that around 14:30)

Justine is also the mind behind Sector LISP, Lambda Calculus in 383 bytes, considerable optimizations to LLamaAI, plus several other things.