The Boot Process

March 1, 2009

When you sit down and power the machine on, the first thing that happens is that the system BIOS loads the underlying programs that fire up the computer. The last thing the BIOS does is to load the Master Boot Record (MBR) data into memory.

1. The MBR contains code that locates the system bootable partition.
2. From the system partition, NTLDR executes and gets the operating system startup process rolling.
3. This brings us to the BOOT.INI file. NTLDR locates and reads the BOOT.INI file for information such as which operating system to launch, where to find the appropriate files to launch that system, and boot menu items.
4. The boot menu displays.
5. NTDETECT.COM launches.
6. NTOSKRNL.EXE runs and the HAL is loaded.
7. Low-level system device drivers load.
8. Operating system kernel and subsystems load and initialize.
9. Any remaining drivers and services are loaded, and Windows 2000 is up and running.

Boot Files and Locations:

NTLDR: System  partition root (e.g. “C:\”)
BOOT.INI: System partition root (e.g. “C:\”)
BOOTSECT.DOS: System partition root (e.g. “C:\”) Only needed on multi-boot systems with Windows 9x/Me
NTDETECT.COM: System partition root (e.g. “C:\”)
NTBOOTDD.SYS: System partition root (e.g. “C:\”) Only used if system partition is on SCSI disk with BIOS disabled
NTOSKRNI.EXE: %SystemRoot%\System32 (e.g. “C:\WINNT\System32”)
%SystemRoot%\System32 (e.g. “C:\WINNT\System32”)
%SystemRoot%\System32\Config (e.g. “C:\WINNT\System32\Config“)

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