Specifications

210 Version 2.0

The change of the number or physical connection of hardware which can have child

hardware devices will be considered as hardware configuration change.

Example:

A.2.2.1 Hardware configuration change example

1. Change IDE disk from IDE primary master to slave

2. Change USB device from port0 to port1

3. Add or remove a SCSI controller adapt card

A.2.2.2 Hardware configuration not change example

1. Remove floppy/cdrom disk in drive will not affect mapped names of other

existing names

2. Remove floppy/cdrom, then insert back, the newly mapped name will be the

same as the last time it was mapped.

3. Unplugging a usb device will not affect mapped names of other existing names

4. Unplug usb device, then plug back to the same port, the newly mapped will be

the same as the last time it was mapped.

A.2.3 Mapping generated from device path

The device path is used to generate the mapping, because in a platform, the device

path is unique and if the hardware configuration doesn’t change, the device’s device

path doesn’t change.

A.2.4 Consistent Mapping

A consistent mapping consists of 3 parts:

MTD(Media Type Descriptor): A string carries device’s media info (harddisk, CD-

ROM, …etc.)

1. Auxiliary name of media type, determined by device path

2. Matches with EFI device path specification

3. Proposed name (hd for harddisk, cd for CD-ROM, fp for floppy, etc.)

HI(Hardware Index): The index of the hardware device path node described in

current device path. The index is determined by the position of the whole sorted

hardware device path node in system.

1. Extract the hardware device path node and ACPI device path node from each

device path in system, make a condensed device path.

Formatted: Bullets and Numbering