Utilities; Extensible Firmware Interface (Efi) Boot Manager; Figure 4-1. Efi Boot Sequence - HP Integrity rx1620 Operation Manual

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Utilities

Extensible Firmware Interface (EFI) Boot Manager

EFI (Extensible Firmware Interface) is an OS and platform-independent boot and pre-boot interface. EFI lies
between the OS and platform firmware, allowing 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 systems, 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 system partition. An
EFI-defined system partition is required by EFI to boot from a block device.
Figure 4-1 EFI Boot Sequence
EFI
Driver
Platform
Init
Standard
firmware
platform
initialization
Application Program
Interface (API) specified
Chapter 4
EFI
Application
EFI Image
Load
Drivers and
application
loaded
iteratively
Boot manager
EFI
Bootcode
Retry
Failure
EFI
OS Loader
Load
Boot from
ordered list
of EFI OS
loaders
Value add implementation
EFI transfers
OS Loader
EFI API
Boot Services
Terminate
Operation
handed off to
OS Loader
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