PMDD.SYS

This driver installs the pointer draw device driver support. It provides pointer draw device-driver support for OS/2 sessions.

All input, whether from keyboard, mouse or other input devices such as touch-sensitive screens and digitizers, is passed from the physical device driver to the PMDD.SYS device driver, which converts it into a message. This includes mouse movement, mouse button actions (down, up) and key events (key down, key up). These messages are placed on the system input queue.

PMDD.SYS is the interface layer between the presentation manager and the device drivers. This device driver is not specific to video drivers. It is also used as the interface for other device drivers; such as sound cards, PCMCIA, or SCSI devices. Video seems to be the most common cause, although there have been several cases of other device drivers causing the same problem. In prior versions of OS/2, the same problem occurred, but only displayed a blank screen. In OS/2 Warp versions, instead of a blank screen, you see a trap screen.

CONFIG.SYS
DEVICE=C:\OS2\BOOT\PMDD.SYS