MAME 0.112 commandline (scaling?)

Okay this is probably a stupid noob question but… how the heck can you scale the screen via commandline? I thought using DirectDraw and Prescale 2 would have done it, but alas it does not. I don’t want to specify a resolution because I want the game to use it’s default. So how would I go about increasing the windowed screen size to 2x? I’ve read the Windows.txt document and it really doesn’t say how to achieve this.

Can anyone help me out.

Soooo… this doesn’t work for anyone? All I want to do is allow newer MAME version to open a window to 2x it’s normal size, similar to the way MAME 0.64 does. 1x is far too small for my current resolution. Sure I can resize the window myself and keep the aspect ratio, but 99.99% of the time I’m going to end up with a nasty black border, which is what I’m trying to avoid.

So why doesn’t Prescale 2 do anything? Someone’s got to know how to do this.