BIOS is an acronym for Basic Input or Output System, also known as System Setup. BIOS is firmware that is embedded on the computer's system board or motherboard. It acts as an interface between the computer's hardware and the operating system. BIOS/UEFI is where we enable the Legacy option to make ThinC-COMPUTE visible in the Boot Menu. In the newer PC/laptops Legacy boot is not enabled which needs to be enabled manually.