Win32 has a default set of 8 thread priorities (lowest to highest). WINCE/WEC7 (realtime operating system) has (like VxWorks) an integer range of priorities from 0-255. Although there is an API to set/get OSPriority it results in a call to SetThreadPriority. This only allows setting values of 248 through 255. For access to the full range of realtime priorities, CeSetThreadPriority should be used. Any changes should also be supported by the Timer, i.e. being able to assign a OSPriority (0-255) for a timer task.