The basic software information for the Microsoft OS/2 version 1.x subsystem is found in the following Registry path:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\OS/2 Subsystem for NT
The OS/2 Subsystem key contains several subkeys, but initially only the \config.sys subkey contains an entry. This subkey contains the OS/2 CONFIG.SYS information stored after an OS/2 application has been run on the system.
If there is no OS/2 CONFIG.SYS file, this subkey contains the following entry:
PROTSHELL=/os2\pmshell.exe /os2\os2.ini /os2\os2sys.ini
%SystemRoot%\system32\cmd.exe
SET COMSPEC=%SystemRoot%\system32\cmd.exe
The Os2 subkey under CurrentControlSet\Control\Session Manager\SubSystems defines the path to the executable file used to start the OS/2 subsystem. The Os2LibPath value under the Session Manager\Environment subkey defines the directory path for the OS/2 library. These entries are described in "CurrentControlSet\Control Subkeys," earlier in this chapter.
To disable the OS/2 subsystem, set the value of GlobalFlag to 20100000 in the following subkey:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager