In Mike Meyers CompTIA A+ book, he says
In early computers, the keyboard connected to the external data bus via a special chip known as the keyboard controller. Don’t bother looking for this chip on your motherboard—the Southbridge now handles keyboard controller functions
Later on he says
As alluded to earlier, the system ROM holds BIOS for more than just the keyboard controller. It also stores programs for communicating with the floppy drive, hard drives, optical drives, display devices, USB ports, and other basic devices on your motherboard.
Is the keyboard controller held in the Southbridge or is it held in the system ROM?
2 Answers
What it means is the program that utilises the keyboard controller is held in ROM. The device to be controlled is in the south bridge but the instructions (aka software/machine code) are held in BIOS.
BIOS stands for Basic Input/Output System. ROM for Read Only Memory, to be current what is referred to as ROM is more likely to be EEPROM or Flash Memory. Though it is ROM for the purposes of 'not normally writeable' or 'read only'.
BIOS stands for Basic Input Output System. It is a ROM (Read Only Memory) chip that contains the instructions and drivers (like an interpreter) for the motherboard to enable the boot process and basic operations until the OS (Operating System) files are loaded. When the OS loads it will overwrite the BIOS data (16 bit) with the appropriate drivers for the type of OS (32 bit or 64 bit.) The keyboard controller function is built in to the South Bridge, or Hub, depending on the platform or chipset. It requires a driver to function properly.
