Comment by yjftsjthsd-h
4 hours ago
> It executes code before the operating system but doesn't really provide a hardware abstraction layer like BIOS does.
Yes it does? If anything, it provides way more; a .efi program can use firmware services to load files and print text. There's like 80% of a DOS in there.
> Most operating system don't use BIOS or any other software layer and configure the hardware themselves. Why is it there then?
Because we still want enough functionality to load the OS in the first place, which means e.g. nvme drivers, Ethernet drivers (for netboot), keyboard input and some display output (to let a user pick what to load), and of course filesystem drivers because loading an OS/bootloader from a single shared MBR was awful.
they also provide device trees to the kernel on modern arm uefi environments. And in servers they provide an interface for the baseboard management controller to interact with the firmware directly.