User Service Guide, Third Edition - HP Integrity rx4640 Server

C Utilities
This appendix describes the utilities that are part of the HP Integrity rx4640 server. These include
the EFI boot manager, and EFI-POSSE.
Extensible Firmware Interface Boot Manager
Extensible Firmware Interface (EFI) is an OS and platform-independent boot and pre-boot
interface. EFI resides between the OS and platform firmware. This enables the OS 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 OS.
NOTE: EFI and Pre-OS System Environment (POSSE) are similar. EFI is an Intel specification,
whereas POSSE is the HP implementation that aids 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 allows 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 server partition.
An EFI-defined server 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 [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
systems.
The EFI boot manager allows you to control the server’s booting environment. Depending on
how you have configured the boot options, after the server is powered up the boot manager
Extensible Firmware Interface Boot Manager 133