An embedded system is a system which can’t be used location independent
… that means it needs a specific environment for its operation.
You can move a PDA or a desktop PC from one location to an other … it
simple works again.
This is e.g. not possible with a SoftPLC, a settop box or a multimedia
device of a car.
IMHO … QNX is also well suited for small systems and not only
for embedded systems ( → environment dependent systems )