Also known as: BIOS, UEFI
BIOS (Basic Input/Output System) and its modern successor UEFI (Unified Extensible Firmware Interface) are the firmware that brings a computer’s hardware up at power-on and hands control to the operating system.12
Overview
Stored in a chip on the motherboard, this firmware is the first code a CPU runs when power is applied. It performs the power-on self-test (POST), initializes the chipset, memory, and basic devices, then locates a bootable storage device and starts its bootloader, which in turn loads the operating system. Legacy BIOS dates to the early PC; UEFI replaced it with a more capable design supporting large disks, faster boot, and features like Secure Boot.
Where it fits
BIOS/UEFI is the layer between bare hardware and software — without it the machine would not know how to start. It is configurable (boot order, clocks, virtualization toggles) through a setup screen, and it can be updated as flashing firmware. On small SDR capture boards the role is filled by an equivalent bootloader baked into the platform; conceptually the job is the same: wake the hardware, then start the OS that runs GopherTrunk.