Let me clarify how this works.
First of all, it is the
OS/2 installer which acts on these selections. This same program (IBM code) is called at some point to lay down the core operating system files, no matter what distribution you are installing. This behaviour is internal to that program and within that context there is no way to prevent it.
Second, there are three basic options provided with respect to DOS and Win-OS/2 features (not including minor configuration tweaks):
- Install MDOS and Win-OS/2
- Install MDOS but not Win-OS/2
- Do not install MDOS or Win-OS/2
Each of these options demonstrably produces a different result, so the installer certainly doesn't ignore the the setting.
In case (1), the MDOS and WINOS2 (or NLV equivalent) directories are installed and populated, normally totalling about 12 MB of files.
In case (2), the MDOS directory is populated, totalling around 1.6 MB in around 80-odd files, including a fully functional DOS system with fullscreen and windowed session support.
In case (3), the MDOS directory is populated with only 800KB in 31 files, including the VDM kernel, virtual drivers and a few core commands. However, this is a stub system only which (TTBOMK) cannot be run interactively, and probably does not include windowed session support; only the minimum files and drivers which IBM has deemed necessary by the core OS. (There
are OS/2 drivers and low-level systems which require VDM support, hence the presence of this support is to be guaranteed by the OS. This has been corroborated by people whom I consider sufficiently knowledgeable to count as authoritative.)
In other words, the user's selection
is honoured in the sense that the user-level MDOS environment is not installed in the latter case.
Some DOS files are still installed because the core OS requires it, but they do not make up a user-level MDOS environment. "Do not install DOS" should therefore be interpreted to mean "do not install the user MDOS environment". It does not mean "do not install any kind of system VDM support", because the latter is not allowed according to what IBM has deemed to compose the core OS/2 spec.