Windows 2008 Booting Process

The boot process has five major stages: preboot, boot, load, initialization, and logon.

Within each of these stages, several steps take place that load and use files. In each of

these stages, look at the process that is taking place, how the particular files are used, and

what you see on the screen.

Preboot Preboot is the hardware-dependent, Basic Input-Output System (BIOS)-enabled

startup process. It is started either by power coming on or the system being reset. 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.

Boot 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.

Load 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.

Initialization 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.

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

screen is displayed. After a successful logon, the necessary services are started, the Last

Known Good control set is written on the basis of the Clone Control Set, and the startup

programs are started.