The BIOS ("Basic Input/Output System") is a small piece ... firmwares can operate in a BIOS-compatible mode with a thing called the Compatibility Support Module (CSM). With the CSM, modern systems ...

you often do not know in advance how the system will be installed: Whether in the older CSM compatibility mode (Compatibility Support Module, also known as “Legacy”) with the MBR hard disk ...

BIOS stands for Basic Input/Output System and contains essential ... UEFI offers a feature dubbed CSM (Compatibility Support ...

and not a legacy compatibility mode (known as CSM or Compatibility Support Module) which is an alternative on non-UEFI motherboards that some folks have used to run AMD graphics card on older ...