DOS and Win-OS/2 Settings
You can configure your DOS and Windows programs individually when running them on OS/2 using the following settings. As you can see there are quite a few different things you can configure for individual sessions but most of the time you will only need to change one or two values.
Keyboard Settings
- KBD_ALTHOME_BYPASS to allow a DOS program to assign the meaning of the ALT-HOME keyboard combination instead of toggling between window and full screen mode.
- KBD_BUFFER_EXTEND to change the keyboard buffer from 16 bytes to 128 bytes.
- KBD_CTRL_BYPASS to pass control key sequences to the application first before OS/2 handles them.
- KBD_LOCK_RATE to prevent the application from changing the preassigned keyboard repeat rate.
Memory Settings
- DOS_HIGH to load DOS into high memory.
- DOS_RMSIZE to set the base memory size of the VDM to less than 640k.
- DOS_UMB to load DOS TSRs into the upper memory block area.
- DPMI_DOS_API to allow the application to use DPMI to access memory above 640k.
- DPMI_MEMORY_LIMIT to assign the amount of DPMI memory available.
- DPMI_NETWORK_BUFF_SIZE to control the size of the DPMI network translation buffer.
- EMS_FRAME_LOCATION to change the location of the expanded memory frame.
- EMS_HIGH_OS_MAP_REGION to adjust how much expanded memory can be added.
- EMS_LOW_OS_MAP_REGION to set the size of remappable conventional memory.
- EMS_MEMORY_LIMIT to set the total amount of available expanded memory.
- MEM_EXCLUDE_REGIONS to specify memory blocks that expanded and extended memory should not use.
- MEM_INCLUDE_REGIONS to specify memory between 640k and 1Mb that can be used by expanded and extended memory.
- XMS_HANDLES to adjust the number of extended memory block handles.
- XMS_MEMORY_LIMIT to change the amount of extended memory available.
- XMS_MINIMUM_HMA to set the minimum amount of high memory available to use as conventional memory.
Mouse and Touch Screen Settings
- MOUSE_EXCLUSIVE_ACCESS to remove the second mouse pointer when the DOS program creates its own.
- TOUCH_EXCLUSIVE_ACCESS th fix problems with touch screens not working properly.
Printer Settings
- PRINT_SEPARATE_OUTPUT to use separate print spools for separate programs.
- PRINT_TIMEOUT to terminate print jobs where the DOS program does not send an end-of-job.
Video Settings
- VIDEO_8514A_XGA_NOTRAP allow uncontrolled access to the video for better performance of games.
- VIDEO_FASTPASTE to change priorities so that clipboard operations get more CPU.
- VIDEO_MODE_RESTRICTION to restrict the video display mode.
- VIDEO_ONDEMAND_MEMORY to delay allocation of memory to the video buffer until it is needed.
- VIDEO_RETRACE_EMULATION to speed text scrolling.
- VIDEO_ROM_EMULATION to simulate video ROMS.
- VIDEO_SWITCH_NOTIFICATION to tell the DOS program when the program switches to or from full screen mode.
- VIDEO_WINDOW_REFRESH to adjust the screen update frequency.
Other DOS settings
- AUDIO_ADAPTER_SHARING to stop DOS programs that don't require audio from blocking other applications from access to the sound card.
- COM_DIRECT_ACCESS to give the program direct access to COM ports.
- COM_HOLD to stop other applications from taking control of a serial port.
- COM_RECEIVE_BUFFER_FLUSH to control the content of receive data buffers.
- COM_SELECT to specify the particular COM port to use.
- DOS_AUTOEXEC to specify which particular file the session should use as its autoexec.bat file.
- DOS_BACKGROUND_EXECUTION to allow a DOS program to run in the background.
- DOS_BREAK to activate the CTRL-C functionality for this session.
- DOS_DEVICE to specify which devices to load.
- DOS_FCBS to specify the number of control blocks (for DOS 1 and DOS 2 programs).
- DOS_FCBS_KEEP to force OS/2 to retain space for a number of control blocks.
- DOS_FILES to specify how many files the session can have open at once.
- DOS_LASTDRIVE to specify how many drive letters to allocate memory for.
- DOS_SHELL to specify a different command processor to use.
- DOS_STARTUP_DRIVE to specify the location of the DOS operating system that the session should use.
- DOS_VERSION to specify the version number that the session will identify is being used.
- HW_NOSOUND to deactivate sound within the application.
- HW_ROM_TO_RAM to copy ROM BIOS into RAM.
- HW_TIMER to allow direct access to the timer ports.
- IDLE_SECONDS to tell OS/2 how long the program must be idle for before reducing its share of the processor.
- IDLE_SENSITIVITY to set the threshold for polling.
- INT_DURING_IO to enable interrupts during disk read/writes.
- SESSION_PRIORITY to set the priority for the session.
WIN-OS/2 Specific settings
- WIN_ATM enables Adobe Type Manager for font management.
- WIN_CLIPBOARD to allow the session to share the OS/2 clipboard rather than using its own.
- WIN_DDE to allow DDE sharing with OS/2 and other sessions.
- WIN_RUN_MODE to specify standard or enhanced mode.


