DOS or not? cmd.exe Vs command.com

[jwisneski]

hello everyone,

i have windows xp service pk 2, and have just noticed something peculiar to me anyway...there seem to be two DOS executable files in the folder
C:\windows\system32\ i have the following
cmd.exe <--created in 2001
command.com <--created 2004
ntvdm.exe <--created 2004

start>programs>accessories>command prompt will run the cmd.exe file
typing command.com in the run box or at the command prompt will open another window which when clicked on to display properties says IT IS ntvdm
now when attempting to close the command.com window the message
windows cannot end this program...is displayed so i must click end now to exit
i was led to believe that xp/2000 have a DOS emulator not true DOS so what is command.com doing there along with the associated ntvdm.exe file and how are they related to true 16 bit DOS can anybody explain this john

[Tuttle]

cmd.exe is the 32-bit command prompt, and it's the one you should be using exclusively. command.com is the old 16-bit version which runs under emulation, and exists only for backwards compatibility with apps that expect to be able to launch it. The difference in performance should be immediately obvious when you switch from one to the other.

[jwisneski]

hello tuttle,
OK, by the file size cmd=379kb, ntvdm=410kb, and command=49kb i think you are telling me that command.com runs within ntvdm.exe which is the DOS emulator (the vd meaning virtual dos?) the only difference in performance that ive seen is the the command.com DOS will not shut down without help (end task button) but then i don't have any games or applications requiring 16bit dos thanks as always for the help john