D Utilities; Extensible Firmware Interface Boot Manager - HP AB464-9003F Service Manual

D Utilities

This appendix describes the utilities that are part of the server. These include the EFI Boot
Manager, EFI-POSSE, and Integrity iLO 2.

Extensible Firmware Interface Boot Manager

The Extensible Firmware Interface (EFI) is an OS and platform-independent boot and preboot
interface. EFI resides between the OS and platform firmware, enabling the OS to boot without
details about the underlying hardware and firmware. EFI supports boot devices, uses a flat
memory model, and hides platform and firmware details from the OS.
NOTE: EFI and Pre-OS System Environment (POSSE) are similar. EFI is an Intel specification,
whereas POSSE is the Hewlett Packard Enterprise implementation that aids Hewlett Packard
Enterprise support.
EFI consolidates boot utilities similar to those found in PA-RISC systems, such as the Boot
Console Handler (BCH), and platform firmware into a single platform firmware. EFI enables the
selection of any EFI OS loader from any boot medium that is supported by EFI boot services.
An EFI OS loader supports multiple options on the user interface.
EFI supports booting from media that contain an EFI OS loader or an EFI-defined system partition.
An EFI-defined system partition is required by EFI to boot from a block device.
Figure 101 EFI Boot Sequence
The EFI Boot Manager loads EFI applications (including the OS first stage loader) and EFI drivers
from an EFI-defined file system or image loading service. Non-volatile RAM (NVRAM) variables
point to the file to be loaded. These variables contain application-specific data that is passed
directly to the EFI application. EFI variables provides system firmware with a boot menu that
points to all the operating systems, even multiple versions of the same operating system.
The EFI Boot Manager enables you to control the server boot environment. Depending on boot
option configuration after the server is powered up, the Boot Manager presents you with different
ways to bring up the system. For example, you can boot to the EFI Shell, to an operating system
located on the network or residing on media in the server, or to the EFI Boot Maintenance menu.
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