Startup Files

The following files are essential to the startup process. All files listed in Table A-2 are located in the boot or root directory (for example, C:\) of your Windows XP Professional installation.

Table A-2: Essential Startup Files

File Name	Description
Ntldr	Reads the Boot.ini file, presents the boot menu, and loads Ntoskrnl.exe, Bootvid.dll, Hal.dll, and boot-start device drivers.
Boot.ini	Contains options for starting the version of Windows that Setup installs and any preexisting Windows installations.
Ntdetect.com	After the boot selection is made, Ntldr loads and executes this 16-bit real-mode program to query the computer for basic device and configuration information. This information includes the following: The time and date information stored in the system s CMOS (nonvolatile memory). The types of buses (for example, ISA, PCI, EISA, Micro Channel Architecture [MCA]) on the system and identifiers for devices attached to the buses. The number, size, and type of disk drives on the system. The types of mouse input devices connected to the system. The number and type of parallel ports configured on the system.
Pagefile.sys	Contains memory data that Windows is unable to fit into physical RAM. During Startup, the virtual memory manager moves data in and out of the paging file to optimize the amount of physical memory available to the operating system and applications.
Ntbootdd.sys	If either the boot or system drives are SCSI-based, Ntldr loads this file and uses it instead of the boot-code functions for disk access.