HP Integrity rx2660 Server User Service Guide

C Utilities
This appendix describes the utilities that are part of the 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 allows 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 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 90 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 enables you to control the server booting 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 the EFI Boot Maintenance menu.
212 Utilities