BOOT Process Of Windows Server 2008

Here’s the brief description of Windows Server 2008 Boot process.

1. System is powered ON
2. The CMOS loads the BIOS and then runs POST
3. Looks for the MBR on the bootable device
4. Through the MBR the boot sector is located and the BOOTMGR is loaded
5. BOOTMGR looks for active partition
6. BOOTMGR reads the BCD file from the \boot directory on the active partition
7. The BCD (boot configuration database) contains various configuration parameters( this information was previously stored in the boot.ini)
8. BOOTMGR transfer control to the Windows Loader (winload.exe) or winresume.exe in case the system was hibernated.
9. Winloader loads drivers that are set to start at boot and then transfers the control to the windows kernel.

STEP 1:

 The first step is to see what hardware is available and its condition by using the power-on self

test (POST) routine. Next, BIOS executes the initial program load (IPL), which locates the

boot device and, if the device is a hard disk, the master boot record (MBR) is read from

the first sector on the disk. Otherwise, the equivalent information is obtained from the

boot device. From this information, partition information is obtained, the boot sector is

read, and the Windows Boot Manager (Bootmgr.exe) is started. On the screen, you see the

memory check, the identification of hardware, and the search for a boot device.

STEP 2:

 Windows Boot Manager reads the boot configuration data (BCD) and, if there is

more than one boot partition, asks the user to choose a partition and its OS. If a choice is

not made before the timeout, the default partition and OS is loaded. If you are booting

Windows Server 2008, the Windows Boot Loader (Winload.exe) is started. If you have

more than one hardware profile, you are given the option of pressing the spacebar to

select the hardware profile you want to use, for example, if you have a laptop that you

sometimes use with a docking station. If you press the spacebar , you can choose the

hardware profile you want; otherwise, the default profile is used.

STEP 3:

Following the operating system and hardware profile selection, the Windows

Server 2008 “splash” screen is displayed with the moving bars in the center. While this

is happening, Windows Boot Loader loads the operating system kernel, the hardware

abstraction layer that provides the interface between the operating system and a

particular set of hardware, the Registry file, and the drivers for basic hardware devices,

such as the monitor, mouse, and keyboard.

STEP 4:

 The OS kernel is initialized and takes over from the Windows Boot

Loader, bringing up the graphical display and filling the Registry with HKEY_LOCAL_

MACHINE\HARDWARE key, and HKEY_LOCAL_MACHINE\SYSTEM\SELECT

subkey (called the “Clone Control Set”) and loads the remainder of the device drivers.

Finally, the session manager is started, which executes any boot-time command files,

creates a paging file for the Virtual Memory Manager, creates links to the file system that

can be used by DOS commands, and finally starts the I/O subsystem to handle all I/O

for Windows Server 2008.

STEP 5:

 The Windows Server 2008 graphic user interface (GUI) is started and the logon

screen is displayed.