UEFI - BDS Phase

BDS Phase（Boot Device Select）

Why??

BDS通過系統中存在的 Boot Option Variable 來找到並啟動 OS Loader 或 UEFI Application。

Task

1. Initialize console devices base on the ConIn, ConOut and StdErr environment variables.

(初始化根據環境變數Conln 、ConOut 以及 StdErr 的 Console Devices)

2. Attempt to load all drivers listed in the Driver#### and DriverOrder environment variables.

(試著去Load 列在環境變數 Driver####及 DriverOrder上的Driver)

3. Attempt to boot Device from the boot selections list in the Boot#### and BootOrder environment variables.

(試著去Boot在環境變數Boot####以及BootOrder上的 Selections Device)

在這個時後使用者可以看見選單並選擇Boot Device

Console Device：

Console Device 是從 Simple Test Output和Simple Input Protocol 抽象出來的。在UEFI中，能夠產生其中一種或兩種Protocol 的Device都被當作是 Console Device

Console Device Type：

1. VGA Adapters, produce Simple Text Output Protocol.

2. Video Adapters, produce Simple Text Output Protocol.

3.Serial Terminal, produce both Simple Text Output Protocol and Simple Input Protocol.

4.Telnet, produce both Simple Text Output Protocol and Simple Input Protocol.

5. Remote Graphical Displays(HTTP), produce both Simple Text Output Protocol and Simple Input Protocol.

Boot Device的幾種Type:

1.Devices that produce the Block I/O Protocol and are formatted with a FAT file system,  Disk Devices
2.Devices that directly produce the File System Protocol
3.Devices that directly produce the Load File Protocol