HP AD117-9003A-ED3 - Manual (Page 141)

C Utilities
This appendix describes the utilities that are part of the server. These include the EFI Boot
Manager, and Extensible Firmware Interface Pre-OS System Environment (EFI/POSSE).
Extensible Firmware Interface Boot Manager
EFI is an operating system and platform-independent boot and pre-boot interface. EFI resides
between the operating system and platform firmware. This allows the operating system to boot
without having details about the underlying hardware and firmware. EFI supports boot devices;
uses a flat memory model; and hides platform and firmware details from the operating system.
NOTE: EFI and POSSE are similar. EFI is an Intel specification. POSSE is the HP implementation
that helps HP support.
EFI consolidates boot utilities similar to those found in PA-RISC based servers, 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 C-1 EFI Boot Sequence
The EFI Boot Manager loads EFI applications (including operating system operating system first
stage loader) and EFI drivers from an EFI-defined file system or image loading service. Nonvolatile
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
systems.
The EFI Boot Manager enables you to control the server’s booting environment. Depending on
boot option configuration after the server is powered up, the Boot Manager presents you with
Extensible Firmware Interface Boot Manager 141