What is xp?

Some articles on xp:

Master Boot Record - Programming Considerations - MBR To VBR Interface
2.0 - 8.0 / PC DOS 2.0 - 6.3 and Windows NT/2000/XP, do not ... code of OS/2, MS-DOS 2.0 to 8.0, PC DOS 2.0 to 7.10 and Windows NT/2000/XP provides this same interface as well, although these systems do not use it. 2.0-8.0, PC DOS 2.0-7.10, Windows NT/2000/XP/Vista/7 MBRs ...