It's funny. If you read "BIOS" out of context, you see the words "Operating System" in its name but it's actually just a firmware interface, and "UEFI" has "firmware interface" in its name but IMHO it's really an operating system.
UEFI is an operating system but has anyone ported a #Lisp engine to UEFI yet? (*search the web*) Damn, Yes, GNU-EFI did...
@CommonSay At least two times I've solved a practical problem by installing a damn device driver to UEFI (RAMdisk, ISO, and NVMe drivers). Not to say UEFI is a good design but definitely shows it's more powerful than DOS.
@niconiconi so you can do multiple-arity functions in C if you use a preprocessor directive?