Windows application support is provided by default during the installation of OS/2 Version 2.0. If the user wishes not to install Windows support, the appropriate option must be chosen during OS/2 installation.
The OS/2 installation program detects the video resolution of the machine on which it is being installed. If Windows support is selected during "first time" installation, then the following configurations will be applied according to the detected video resolution:
CGA, EGA
Note: Readers should check the ReadMe file in the Information folder for the latest information on this subject. This folder contains information on how to reconfigure the system to have seamless WIN-OS/2 support as well as high resolution MAVDM and/or SAVDM sessions. Additional support information for SVGA display device drivers will be provided as well. OS/2 Version 2.0 - Volume 1: Control Program also discusses several installation and configuration aspects of OS/2 V2.0.
When Windows support is selected at installation time, all the files necessary to provide this support are installed in the following subdirectories:
If the user decides to install Windows application support, DOS application support is automatically installed. OS/2 Version 2.0's CONFIG.SYS file is updated to include the above directories in the PATH statement.
Since Windows real mode requires 640KB of conventional memory and several MB of expanded memory (EMS), the EMS virtual device driver is also required. If the user did not select standard mode at installation time and wishes to add it at later time, the OS/2 Version 2.0 CONFIG.SYS must be modified by adding the following statements:
If these device drivers are not loaded, the Windows kernel will execute in real mode.
Windows can use expanded memory which conforms to the LIM EMS 4.0 specification when running in real mode. This memory is primarily used for storing background applications. In a DOS/Windows environment, an appropriate Expanded Memory Manager must be installed. Under OS/2 V2.0 this is not necessary, as the virtual device driver already provides that service. In standard mode, Windows may also use extended memory (XMS).