Windows Vista Startup Process
Encyclopedia
The startup process of Windows Vista
Windows Vista
Windows Vista is an operating system released in several variations developed by Microsoft for use on personal computers, including home and business desktops, laptops, tablet PCs, and media center PCs...

, Windows Server 2008, Windows 7 and Windows Server 2008 R2
Windows Server 2008 R2
Windows Server 2008 R2 is a server operating system produced by Microsoft. It was released to manufacturing on July 22, 2009 and launched on October 22, 2009. According to the Windows Server Team blog, the retail availability was September 14, 2009. It is built on Windows NT 6.1, the same core...

 is different from any previous versions of Windows. For Windows Vista, the boot sector loads the Windows Boot Manager (with filename BOOTMGR), which first looks for an active partition, then accesses the Boot Configuration Data store and uses the information to load the operating system.

Windows Boot Manager

Windows Boot Manager (BOOTMGR) reads the boot configuration data and displays an operating system selection menu. A notable change is that the Windows Boot Manager is invoked by pressing the space bar
Space bar
thumb|250px|A [[computer keyboard]], Space Bar is on the bottom center of the keyboardThe space bar, spacebar, or space key, is a key on an alphanumeric keyboard in the form of a horizontal bar in the lowermost row, significantly wider than other keys. Its main purpose is to conveniently enter the...

 instead of the F8 function key
Function key
A function key is a key on a computer or terminal keyboard which can be programmed so as to cause an operating system command interpreter or application program to perform certain actions...

. The F8 key still remains assigned for advanced boot options once the Windows Boot Manager menu appears.

To maintain a consistent boot experience on Extensible Firmware Interface
Extensible Firmware Interface
The Unified Extensible Firmware Interface is a specification that defines a software interface between an operating system and platform firmware...

 systems that also have a boot manager of their own, the Windows Boot Manager, and hence all of the installed Windows operating systems that can be booted using it, appear as a single entry on the EFI boot manager menu. (On EFI systems, the Windows Boot Manager is an EFI application stored on the EFI System Partition
EFI System Partition
The EFI System partition is a partition on a data storage device that is used by machines that adhere to the Extensible Firmware Interface. It contains the boot loader programs for all operating systems installed on the device, device driver files for other devices, and system utility programs...

). Microsoft only adds multiple entries to the Windows Boot Manager (BCD) menu itself, and sets the timeout of the EFI boot manager to two seconds.

Boot Configuration Data

Boot Configuration Data (BCD) is a firmware-independent database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

 for boot-time
Booting
In computing, booting is a process that begins when a user turns on a computer system and prepares the computer to perform its normal operations. On modern computers, this typically involves loading and starting an operating system. The boot sequence is the initial set of operations that the...

 configuration data. It replaces the boot.ini that was used by NTLDR
NTLDR
NTLDR is the boot loader for all releases of Windows NT operating system up to and including Windows XP and Windows Server 2003. NTLDR is typically run from the primary hard disk drive, but it can also run from portable storage devices such as a CD-ROM, USB flash drive, or floppy disk...

, and is used by Microsoft's new Windows Boot Manager.

Boot Configuration Data is stored in a data file that has the same format as the Windows Registry
Windows registry
The Windows Registry is a hierarchical database that stores configuration settings and options on Microsoft Windows operating systems. It contains settings for low-level operating system components as well as the applications running on the platform: the kernel, device drivers, services, SAM, user...

. The file is located either on the EFI System Partition
EFI System Partition
The EFI System partition is a partition on a data storage device that is used by machines that adhere to the Extensible Firmware Interface. It contains the boot loader programs for all operating systems installed on the device, device driver files for other devices, and system utility programs...

 (on machines that use Extensible Firmware Interface
Extensible Firmware Interface
The Unified Extensible Firmware Interface is a specification that defines a software interface between an operating system and platform firmware...

 firmware) or in \Boot\Bcd on the system volume
System partition and boot partition
In Microsoft Windows, the system partition and boot partition refer to:*The system partition is a disk partition that contains the boot sector and files such as NTLDR that are needed for booting Windows XP and earlier...

 (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
Windows Management Instrumentation
Windows Management Instrumentation is a set of extensions to the Windows Driver Model that provides an operating system interface through which instrumented components provide information and notification...

, or with third party tools like EasyBCD
EasyBCD
EasyBCD is a free program developed by NeoSmart Technologies to configure and tweak the Boot Configuration Data , a boot database first introduced in Windows Vista...

.

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
    Volume Boot Record
    A volume boot record is a type of boot sector introduced by the IBM Personal Computer...

    .


Boot Configuration Data allows for third party integration so anyone can implement tools like diagnostics or recovery options.

winload.exe

The Windows Boot Manager invokes winload.exe—the operating system boot loader
Booting
In computing, booting is a process that begins when a user turns on a computer system and prepares the computer to perform its normal operations. On modern computers, this typically involves loading and starting an operating system. The boot sequence is the initial set of operations that the...

—to load the operating system kernel (ntoskrnl.exe
Ntoskrnl.exe
ntoskrnl.exe is the kernel image for the family of Microsoft Windows NT operating systems...

) and (boot-class) device drivers. In that respect, winload.exe is functionally equivalent to the operating system loader function of NTLDR
NTLDR
NTLDR is the boot loader for all releases of Windows NT operating system up to and including Windows XP and Windows Server 2003. NTLDR is typically run from the primary hard disk drive, but it can also run from portable storage devices such as a CD-ROM, USB flash drive, or floppy disk...

in prior versions of Windows NT.

Further reading

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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