When you install Windows NT on an x86-based computer, Windows NT Setup puts the Boot.ini file at the root of the system partition. NTLDR uses information in the Boot.ini file to display the screen from which you select the operating system to start.
Here is a sample 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="Windows NT Workstation
Version 4.0" multi(0)disk(0)rdisk(0)partition(1)\WINNT="Windows NT Workstation
Version 4.0 [VGA mode]" /basevideo /sos C:\="Windows 95"
The Boot.ini file has two sections, [boot loader] and [operating system], which are described in the next two sections.