I'm not sure I understand correctly, but you can try using the FreeDOS version of MODE.
http://www.freedos.org/software/?prog=mode

But that won't change the vertical size of the DOSBox window. I think you might be able to scale the window size manually by altering the DOSBox configuration file.

Alternatively, perhaps you will find TameDOS to suit your needs better.
http://www.tamedos.com/

Thank you, Jorpho.
Yes, in fact, I need to regulate vertical size (in pixels) of the DOSBox window independently from it's horizontal size, i.e. to set desired aspect ratio. And I do not understand how to reach this goal with editing of the "dosbox-0.74.conf" file. May be somebody could help?
P.S. TameDOS is not free, so it could not be for me in any case.

You need to change the WindowResolution and Output lines in dosbox.conf, which you can access through the Start menu via DOSBox->Options->DOSBox 0.74 Options.

There are many, many threads on the subject already if you need more details.

Yes, I have seen contents of the "dosbox-0.74.conf" and made some editings of it (in the "autoexec" section). There is "windowresolution" keyword in the file, but not "Output lines"!
Maybe I must to add such a keyword? What is the exact spelling of it and in the which section?

It was about the lines windowresolution and output. Look again, in the first block output is written and normally set to surface.

Yes, there is "output=surface" string in the .conf-file and I have seen it before already.
Commented lines there say nothing about quantity of text lines in text-mode or something like that.
But my question was and is about method for setting size of text-mode window, horizontal and vertical independently, in pixels. And by now, I do not understand how to achieve my goal.

bichuch wrote:

Commented lines there say nothing about quantity of text lines in text-mode or something like that.

But that is not what you want to do. You said:

bichuch wrote:

I need to regulate vertical size (in pixels) of the DOSBox window independently from it's horizontal size, i.e. to set desired aspect ratio.

You will also note that the commented lines state:

1# windowresolution: Scale the window to this size IF the output device supports hardware scaling.
2#                     (output=surface does not!)
3#           output: What video system to use for output.
4#                   Possible values: surface, overlay, opengl, openglnb, ddraw.

So, change "output=" to something else, and then set "windowresolution=" to 640x960 or whatever you like.

Well, I have changed "output=surface" sequentially with "...=overlay", "...=opengl", "...=openglnb", "...=ddraw". Results are:
with "...=opengl[nb]" the window shows nothing (complete black), other variants work normal. But value of "windowresolution=..." have no meaning, with "original", "640x720", "640x960" or commenting out this directive, screen size in pixels of the window is the same...
🙁

Maybe I am doing something in the wrong way.
Jorpho, could you please post a screenshot of the desktop with non-standard sized DOSbox window and attach the .conf file, that made this result?

I did a search and found Making dosbox go from 4:3 to 16:9 , which suggests that the DOSBox window has to be 4:3 or 8:5.

So it turns out the answer is No, there is probably no way to change the screen height, at least not without patching the source code to allow a different aspect ratio. Sorry.

Yes, I see. 😖
We can not change the aspect ratio of a hardware display - DOSbox is a true emulator, that works in the same right way.
I meet one another feature (or bug?): it does not allow to move mouse pointer below 25 line in 50-lines text mode.
And again my question is about fatality of such behaviour. May be some secret method for workaround of that exists?

Problem was solved!
See Mouse pointer does not move below 25 line in the 50-lines text mode. (SOLVED)