R0STUB.SYS

R0STUB.SYS is the ring-0 half of the sync-stream-manager (SSM) that allows MMPM/2 to synchronize audio and video. Allows AUDIOSH.DLL to talk to audio drivers via IDC entry point. In the beginning, all the streaming took place at ring-0. Later (Warp 3?), the audio streaming was moved to ring-3. The API still had to be maintained to audio driver. R0STUB is small piece of code that takes FIFOs buffers to/from MMPM/2 ring-3 audio stream handler and delivers them from/to the hardware vendor audio device driver.

CONFIG.SYS
DEVICE=\MMOS2\R0STUB.SYS