Criticism of Windows XP - Backward Compatibility

Backward Compatibility

Migrating from Windows 9x to XP can be an issue for users dependent upon MS-DOS. Although XP comes with the ability to run DOS programs in a virtual DOS machine, it still has trouble running many old DOS programs. This is largely because it is a Windows NT system and does not use DOS as a base OS, and because the Windows NT architecture is different from Windows 9x. Some DOS programs that cannot run natively on XP, notably programs that rely on direct access to hardware, can be run in emulators, such as DOSBox or virtual machines, like VMware, Virtual PC, or VirtualBox. This also applies to programs that only require direct access to certain common emulated hardware components, like memory, keyboard, and serial ports.