I don't get why it's "-os" myself. Case in point:

-w3d - weak 3D
-wnd - force windowed mode
-nx ### - set nexus to this value (in megabytes)

They all use a similar system. "-os", however, doesn't. "-ns" would make more sense for "no sound". As far as I can hypothesize, the "o" must be relate to the German way to say "no sound". I don't know German so I'm unable to verify this.

"You level up the fastest and easiest if you do things at your own level and no higher or lower" - useful tip My 2D game - release on Jun 13th; My tutorials