process scheduling in QNX

I want to know about the scheduling algorithm that QNX uses to preempt a

task.Is it like Rate Manotonic scheduling or Earliest Deadline First

scheduling ?One more thing I want to know, in QNX the context switching is

very fast. How it manages internally to manage the context switch fast.In

one of the article about the basic concepts of RTOS which I got from

internet, I found that RTOS generally uses “incrementally updated table”

avoid the search of a long queue of process to know which process should

next.If it is like this then please give some more details about the

management of “incrementally updated table”.

Thanking you in advance.

Jitendra Sasmal