How to run DOS program in WinXP?

Just a friend asked me how to upgrade my system to Windows XP, but some old typesetting software needs to run under DOS, and Windows XP has no pure DOS. How should I run DOS program?
Simply say you can use the start command to run. In the Windows XP command prompt, type: start/seperate to run the program, you can run the corresponding DOS program. The function of the parameter separate is to start a 16-bit program in a separate memory space, and the shared parameter is to start a 16-bit program in the shared memory space. When the DOS program is running, we can also switch between full screen and window by pressing the <Alt+Enter” key.