It's just a version #. It's not actually MS-DOS.

Currently some readme files (not all of them) includes a description about it:
One of the DOSBox authors wrote in a thread a while ago, how to set it, I can't find this thread yet, so I repeat it here (it's a very interesting feature, introduced with 0.70).
Type in:

ver set 6 22

You get the result:

1DOSBox version 0.72. Reported DOS version 6.22

So the version number can be changed to practically anything... but it's not even an actual DOS.

How comes it, then, that this "virtual DOS" can run programs written for real DOS?

-- B.D.T.

What is DOS?

IO.SYS
MSDOS.SYS
Command.com

That's it. (except of course for the hardware required to run it).

DosBox emulates only what it needs to of MS-DOS for games to work. In a sense it is an "actual DOS", just an emulated DOS.

most application don't care much for the version number.
if it's higher (or equal) then 3 they are usually happy (as you then have the new file support functions). higher versions of dos
didn't add that much special for games.

So I could in DOSBox set the "version" to 3.0 or above, and the game would work, correct? Anything below 3.0 and the game would fail.

-- B.D.T.

It depends on the game requirements... Games developped before DOS 3.n will work, obviously.

So, what one sets for the "ver" command actually DOES make a difference in the "version" as far as running the right game for the right DOS.

But it seems to me that changing the "version" apparently has no effect whatsoever on anything besides that.

Right?

-- B.D.T.

Look, if you want real DOS then boot real DOS.

DosBox is not MS-DOS. Never will be. We don't want it to be.

Changing the version # is just that. It changes the # because the program\game looks for a specific version #.

Jeez! Well, that seems to have answered my questions.

I was only asking to make sure I knew what DOSBox was all about.

-- B.D.T.

What DOSBox is about can be defined in very few words: To provide the best possible way to play old DOS games on new PC's.