As we knew that most QNX service and utilities use default highest priority 21 and lowest priority 10. For example, io-
net use priority level 21 for interrrupt handling, and io-hid, io-usb, etc. Therefore there will be left 20~10 priority 
level ranges for normal user applications.

As I knew the history coming from QNX 4 that only 32 priorities. It make sense that io-net and io-hid use 21 as default.
 However, QNX 6 has 255 priority levels and io-usb/io-hid still uses 21 which did NOT extend priority range for user 
applications. 

For example, if there are six applications reside on the same CPU each need 10 thread priority levels (Our target 
porting from legacy system which has six independent CPUs for each application). There will be totally 60 threads needed
. Even the priority levels can be simplified to 30 levels after review. The default ten (20~10) priority level range is 
still too few.

As I knew that io-net can adjust priority by "'priority=50' to extend user application level range to 49~10. However, io
-hid an d io-usb have no way to adjust. 

Therefore, is any QNX technical article or guideline to adjust QNX default priority for specific services?