Extensible Firmware Interface Specification
360 12/12/00 Version 1.02
BIOS Boot Specification Device Path
A Device Path that is used to point to boot legacy operating systems; it is based on the
BIOS Boot Specification, Version 1.01.
BIOS Parameter Block (BPB)
The first block (sector) of a partition. It defines the type and location of the FAT File
System on a drive.
Block I/O Protocol
A protocol that is used during boot services to abstract mass storage devices. It allows
boot services code to perform block I/O without knowing the type of a device or its
controller.
Block Size
The fundamental allocation unit for devices that support the BLOCK_IO protocol. Not
less than 512 bytes. This is commonly referred to as sector size on hard disk drives.
Boot Device
The device handle that corresponds to the device from which the currently executing
image was loaded.
Boot Manager
The part of the firmware implementation that is responsible for implementing system
boot policy. Although a particular boot manager implementation is not specified in this
document, such code is generally expected to be able to enumerate and handle transfers
of control to the available OS loaders as well as EFI applications and drivers on a given
system. The boot manager would typically be responsible for interacting with the system
user, where applicable, to determine what to load during system startup. In cases where
user interaction is not indicated, the boot manager would determine what to load and, if
multiple items are to be loaded, what the sequencing of such loads would be.
Boot Services
The collection of interfaces and protocols that are present in the boot environment. The
services minimally provide an OS loader with access to platform capabilities required to
complete OS boot. Services are also available to drivers and applications that need
access to platform capability. Boot services are terminated once the operating system
takes control of the platform.
Boot Services Driver
A program that is loaded into boot services memory and stays resident until boot services
terminates.
Boot Services Table
A table that contains the firmware entry points for accessing boot services functions such
as Task Priority Services and Memory Services. The table is accessed through a
pointer in the System Table.