Keil RTOS for ARM

Gentlemen (Ladies):

I'm confused: when looking at documentation/marketing literature for Keil's Real-Time OS products for the ARM achitecture, I come across what looks like the same product but which appears to be referred-to four different ways:

1.) ARTX (Advanced Real Time Executive?)

2.) RTX (Realtime Kernel)

2.) RL-ARM (RealView RealTime Library)

3.) RTL-ARM (RealView RTL-ARM RTOS)

Anybody know which is which? I also found documentation on the Keil site for the RL-ARM product. But when I opened it up, it referred to the RTOS as ARTX!

Can anyone shed some light on this? Herr Keil?

Thanks in Advance,

-=Rich=-