Boot Configuration Data
Boot Configuration Data (BCD) is a firmware-independent database for boot-time configuration data. It replaces the boot.ini that was used by NTLDR, and is used by Microsoft's new Windows Boot Manager.
Boot Configuration Data are stored in a data file that has the same format as the Windows Registry. The file is located either on the EFI System Partition (on machines that use Extensible Firmware Interface firmware) or in \Boot\Bcd on the system volume (on machines that use IBM PC compatible firmware).
Boot Configuration Data may be altered using a command-line tool (bcdedit.exe), using Registry Editor (regedit.exe), using Windows Management Instrumentation, or with third party tools like EasyBCD.
Boot Configuration Data contain the menu entries that are presented by the Windows Boot Manager, just as boot.ini contained the menu entries that were presented by NTLDR. These menu entries can include:
- Options to boot Windows Vista by invoking winload.exe.
- Options to resume Windows Vista from hibernation by invoking winresume.exe.
- Options to boot a prior version of the Windows NT family by invoking its NTLDR.
- Options to load and to execute a volume boot record.
Boot Configuration Data allows for third party integration so anyone can implement tools like diagnostics or recovery options.