Starting Up Windows 2000 and Boot Sequence

Starting Up Windows 2000

Remember The Windows 2000 startup process is very different from the process used to start up MSDOS, Windows 95, or Windows 98. In these systems, the IO.SYS file is loaded followed by the MSDOS.SYS and COMMAND.COM program. Windows 2000 does not use these files, and you will only find them on PCs that are configured for a multi-boot and early Windows version or MS-DOS.

The general startup sequence used to start a Windows 2000 system is

l Power-on self test (POST): This is the same regardless of the operating system.

l Initial startup: After the POST, the system BIOS looks for the disk from which it should start the operating system. The storage devices are checked in the sequence prescribed in the BIOS. A number of different error messages can be displayed if the operating system is not found.

l Instant Answer Bootstrap loader: The bootstrap loader program NTLDR loads the operating system's files into memory from the boot partition. If the PC is set to Multiboot, a multiple-boot menu is displayed from which the operating system to be started is chosen. NTLDR processes the operating system selection and the hardware detection processes before passing control to the Windows 2000 kernel. NTLDR must be located in the root directory of the boot partition.

l Operating system selection: If the PC is configured as Multiboot, the system file BOOT.INI contains the list of available operating systems, including the path to its boot partition. Windows 2000 can multiboot with multiple Windows 2000 versions, as well as Windows 95, Windows 98, Windows NT 4.0, MS-DOS, and OS/2.

Here is an example of the contents in the BOOT.INI file:

[boot loader]

timeout=30

default=multi(0)disk(0)rdisk(0)partition(1)\WINNT

[operating systems]

multi(0)disk(0)rdisk(0)partition(1)\winnt= "Microsoft Windows 2000

Professional" /fastdetect

C:\="Windows 98"

l Hardware detection: After the operating system is selected on a multiboot PC, or when only Windows 2000 is on the PC, NTDETECT.COM detects the hardware, creates a list of the installed hardware, and passes the list to NTLDR. The information that NTDETECT.COM passes includes the computer ID and information on the bus and adapters installed, keyboard, COM ports, floppy disk controller, mouse, and LPT ports.

l Hardware profile selection: Windows 2000 supports more than one hardware profile to allow for multiple non-Plug and Play configurations of the PC. If multiple hardware configurations are defined, NTDETECT.COM prompts for the hardware profile to use. If only one hardware profile is in use, the default settings are used. One choice available on the hardware profile screen is the Last Known Good Configuration, which will overlay all changes in the Registry and control set since the last good boot. After the hardware profile is chosen, control passes back to NTLDR.

l Windows 2000 kernel loads: NTLDR loads the Windows 2000 kernel and the hardware abstraction layer (HAL) into memory. (See "Meeting HAL" later in this section.) NTLDR then loads the registry key HKEY_LOCAL_ MACHINE\SYSTEM from the folder %SystemRoot%\system32\Config\ System and uses it to create the control set that is used to initialize the PC. This control set is used to start the operating system.

l Logon: WINLOGON.EXE and the Local Security Administration are started and the Begin Logon box is displayed. Windows 2000 is still loading drivers and such, but you can log in. After the logon is complete, the Desktop is displayed and the Last Known Good control set is created.