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Extensible Firmware Interface Specification
Glossary-12 12/01/02 Version 1.10
PCI Root Bridge I/O Protocol
A software abstraction that provides access to the PCI I/O, PCI Memory, and PCI
Prefetchable Memory regions in a single Coherency Domain.
PCI Root Bridge A chipset component(s) that produces a physical PCI Local Bus.
PCI Segment A collection of up to 256 PCI Buses
that share the same PCI Configuration
Space. PCI Segment is defined in section 6.5.6 of the ACPI 2.0 Specification as
the _SEG object. The SAL_PCI_CONFIG_READ and
SAL_PCI_CONFIG_WRITE procedures defined in chapter 9 of the SAL
Specification define how to access the PCI Configuration Space in a system that
supports multiple PCI Segments. If a system only supports a single PCI Segment
the PCI Segment number is defined to be zero. The existence of PCI Segments
enables the construction of systems with greater than 256 PCI buses.
Pool Memory A set of contiguous bytes. A pool begins on, but need not end on, an “8-byte”
boundary. Pool memory is allocated in pages—that is, firmware allocates
enough contiguous pages to contain the number of bytes specified in the
allocation request. Hence, a pool can be contained within a single page or extend
across multiple pages. Pool memory is allocated by AllocatePool()
and
returned by FreePool()
.
Preboot Execution Environment (PXE)
A means by which agents can be loaded remotely onto systems to perform
management tasks in the absence of a running OS. To enable the interoperability
of clients and downloaded bootstrap programs, the client preboot code must
provide a set of services for use by a downloaded bootstrap. It also must ensure
certain aspects of the client state at the point in time when the bootstrap begins
executing.
The complete PXE specification covers three areas; the client, the network and
the server.
Client
- Makes network devices into bootable devices.
- Provides APIs for PXE protocol modules in EFI and for universal
drivers in the OS.
Network
- Uses existing technology: DHCP
, TFTP, etc.
- Adds “vendor-specific” tags to DHCP to define PXE-specific operation
within DHCP.
- Adds multicast TFTP for high bandwidth remote boot applications.
- Defines Bootserver discovery based on DHCP packet format.
Server
Bootserver: Responds to Bootserver discovery requests and serves up
remote boot images.
proxyDHCP: Used to ease the transition of PXE clients and servers into
existing network infrastructure. proxyDHCP provides the additional