C-1. Legacy Floppy Device Path; C.3 Ide Disk - Intel Extensible Firmware Interface Specification

Table C-1. Legacy Floppy Device Path
Byte Byte
Offset Length
0 1
1 1
2 2
4 4
8 4
C 1
D 1
E 2
10 1
11 1
12 1
13 1
14 2
16 4
1A 4
1E 1
1F 1
20 2

C.3 IDE Disk

The IDE Disk controller is a PCI device that is contained in a function of the root PCI host bridge.
The root PCI host bridge is a multi function device and has a separate function for chipset registers,
USB, and IDE. The disk connected to the IDE ATA bus is defined as being on the primary or
secondary ATA bus, and of being the master or slave device on that bus.
In ACPI this configuration is represented in the _SB, system bus tree, of the ACPI name space.
PCI0 is a child of _SB and it represents the root PCI host bridge. The IDE controller appears to the
system to be a PCI device with some legacy properties, so it is represented as a child of PCI0 with
the name IDE0. PRIM is a child of IDE0 and it represents the primary ATA bus of the IDE
controller. MAST is a child of PRIM and it represents the that this device is the ATA master
device on this primary ATA bus.
Version 1.02
Data Description
0x02 Generic Device Path Header – Type ACPI Device Path
0x01 Sub type – ACPI Device Path
0x0C Length
0x41D0, _HID PNP0A03 – 0x41D0 represents a compressed string 'PNP' and is in
the low order bytes
0x0A03
0x0000 _UID
0x01 Generic Device Path Header – Type Hardware Device Path
0x01 Sub type PCI Device Path
0x06 Length
0x00 PCI Function
0x10 PCI Device
0x02 Generic Device Path Header – Type ACPI Device Path
0x01 Sub type – ACPI Device Path
0x0C Length
0x41D0, _HID PNP0303
0x0303
0x0000 _UID
0xFF Generic Device Path Header – Type End Device Path
0xFF Sub type – End Device Path
0x04 Length
12/12/00
Device Path Examples
339