To fulfill RTSS applications memory requests, RTX deterministically allocates memory from a special memory pool (Local memory pool).
RTSS applications that allocate memory from that pool don't have to initiate a Service Request Interrupt to request memory from Windows (this request would be non-deterministic). If the memory needs of the RTSS application exceeds the initial size of the local memory pool, RTX initiate a non-deterministic Service Request Interrupt to request memory from Windows.
This action is signaled to the user via a driver "warning message".
This scenario can be avoided, by increasing the initial local memory pool size to the memory needs of the driver and the RTSS application (see memory settings in the RTX properties application). If the creation of the local memory pool is not done at startup, but with the first call to a local memory pool allocation function the drivers warning message is also signaled. The creation of the local memory pool at startup is initiated, a) by executing the RTSS application with the parameter /local or b) by modifying the memory settings in the RTX properties application (see RTX Manual).