Original: NTFS is the standard file system of Windows NT, including its later versions Windows 2000, Windows XP, Windows Server 2003, Windows Server 2008, Windows Vista, and Windows 7.
Simplified: A version of NTFS is also included in the most recent operating systems developed by Microsoft, Windows XP, Windows Server 2003 and Windows Vista. NTFS was made to replace the old file-system used by earlier versions of Windows, like Windows 95, Windows 98, and Windows 98SE.