Hello, I seen the C251 Development Tools, as in large programs RTOS is required; in C251, which RTOS we have to use; Same as RTX51 (Full) or not available.
We do not supply any operating system for 251, but to our knowledge CMX provides a operating system for Keil C251.
I searched the keil.com and found few articles for RTX251, and i found one PDF manuals on net for RTX51 / 251 both, our application required RTOS; we presently using code banking with our own written RTOS; but having some problem; As seen RTX tiny in C51, feel RTX51 Full is more interesting; the other option is switch to 251 with Standard RTOS like RTX51; any way; better we transplant own RTOS to RTX51.