c - Understanding the hardware of printf

Question

I was wondering if there was any resources available online that explains what happens with something, like printf of C, that explains what's going on in the very low level (BIOS/kernel calls)

Answer 1

Linux:

printf() ---> printf() in the C library ---> write() in C library ---> write() system call in kernel.

To understand the interface between user space and kernel space, you will need to have some knowledge of how system calls work.

To understand what is going on at the lowest levels, you will need to analyze the source code in the kernel.

The Linux system call quick reference (pdf link) may be useful as it identifies where in the kernel source you might begin looking.