Administrator Guide

7 : BIOS vs. UEFI | Doc ID 20444677 | June 2018
separate interface for hard-disk or RAID configuration. Most boot devices require a system reboot after any
firmware change, so system configuration requires multiple boots.
UEFI defines a shared user interface known as the Human Interface Infrastructure (HII). A user can configure
all the firmware settings - including BIOS, onboard management controller, and boot devices – using a single
user interface, without needing a reboot between changes for each device. HII also facilitates remote
configuration of all firmware settings via baseboard management controller interfaces.
2.4 Resource Allocation for Boot Device Firmware
Traditional BIOS implementations offer limited memory space for boot device firmware. Boot devices such as
storage controllers and network interface controllers require increasing amounts of memory to execute their
firmware during the boot process. When a system contains multiple boot devices, a traditional BIOS may not
allocate enough memory space for all of the device firmware to execute.
UEFI eliminates this limitation by defining standard interfaces for memory management. In UEFI boot mode,
boot devices use these interfaces to request memory space from the BIOS memory manager. When a system
contains multiple boot devices, UEFI boot mode allocates memory on-demand for each device’s firmware.