I disagree. When someone says "Don't do multitasking on an 8051," that person obviously knows there's a wide range of 8051's to choose from. It's not the 8051 architecture that dictates whether or not multitasking is reasonable, it's potentially the speed and/or the amount of memory available. Not the architecture.

I disagree somewhat. The 'standard' RTOS mechanism is the functon pointer and the implications of squeezing that into the '51 are well known. The function pointer itself is just one of the problems, the fact that, for efficiency, you need "call tree allocation" of function parametres instead of the 'standard' "put them on the stack" makes the whole thing a total mess.

Thus, to implement a full fledged RTOS on a '51 you need to bastardize the architecture with an artificial stack in XDATA and, eventually you end up that the 'speed demon' you bought becomes a slowpoke.

Does all this mean that a RTOS is "wrong" for the '51?, of course not BUT it means that choosing to use a RTOS should not be an out of the gate decision.

Erik