Booting process of Windows NT: Difference between revisions

Revision as of 15:49, 4 May 2023

Revision as of 02:42, 7 May 2023

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=== Operating system selection ===

[[File:Windows_Boot_Manager_with_Windows_7,Vista_and_XP.png|thumb|260x260px|Windows Boot Manager (BOOTMGR) with Windows 7 highlighted and options to load Windows Vista through BOOTMGR and XP through NTLDR.]]

The boot loader, once executed, searches for Windows operating systems. Windows Boot Manager does so by reading [[Boot Configuration Data]] (BCD), a complex firmware-independent database for boot-time configuration data. Its predecessor, <code>NTLDR</code>, does so by reading the simpler <code>[[boot.ini]]</code>. If the boot.ini file is missing, the boot loader will attempt to locate information from the standard installation directory. For Windows NT and 2000 machines, it will attempt to boot from <code>C:\WINNT</code>. For machines running Windows XP and, 2003, machinesand later, it will boot from <code>C:\WINDOWS</code>.

Both databases may contain a list of installed Microsoft operating systems that may be loaded from the local hard disk drive or a remote computer on the [[local area network|local network]]. NTLDR supports operating systems installed on disks whose file system is [[NTFS]] or [[File Allocation Table|FAT]] file systems, CDFS (ISO 9660) or [[Universal Disk Format|UDFS]].<ref>{{cite web |date=October 26, 2007 |title=Unified Extended Firmware Interface support in Windows Vista (Revision: 1.5) |url=http://support.microsoft.com/kb/930061 |access-date=October 30, 2011 |work=Microsoft Support |publisher=Microsoft Corporation}}</ref> Windows Boot Manager also supports operating systems installed inside a [[VHD (file format)|VHD]] file, stored on an NTFS disk drive.<ref>{{cite web |date=February 20, 2009 |title=Boot from VHD in Win7 |url=https://technet.microsoft.com/en-us/edge/boot-from-vhd-in-win7.aspx |access-date=October 30, 2011 |work=[[Microsoft TechNet|TechNet Edge]] |publisher=Microsoft Corporation}}</ref>