LHS Feature Of The Week #7 - Boot Configuration Data
Hello everyone, and welcome back to the “Feature Of The Week” newsletter. This week, we will be looking at the robust replacement for boot.ini in Windows Vista and Longhorn Server: Boot Configuration Data.
What is Boot Configuration Data? Boot configuration data (BCD) provides a store that is used to describe boot applications and boot application settings. The objects and elements in the store effectively replace Boot.ini. The data in the store can be managed by a command-line utility, bcdedit.exe, or using the classes implemented by the WMI provider.
How does Boot Configuration Data work? When you start your computer, the first code that executes is the BIOS. The BIOS reads the master boot record (MBR) from the boot device and transfers control to the boot code stored in the MBR. The boot manager reads the boot entries from the Boot Configuration Data store so they are available to the loader and displays a boot menu to the user. The boot environment provides a native API for primitive graphics and other system support. Boot applications are pieces of code that are located on a boot device and run in the boot environment.
The following are examples of application objects:
• The Windows Boot Manager
• The Windows OS Loader
• The Windows Memory Tester
Example – Now, with the absence of the boot.ini file, this is how you would enable Kernel debugging on a system as a boot option: “bcdedit /debug true”