Thanks Michael,

Unfortunately I bought the TI kit (hardware & stack(s)) not realising that it was dependant on a compiler that cost £2000. I am a research student and the academic budget wonte run to that. The 4K code limit eval copy I have wonte even build the example apps they provide. Even if I could use it I guess one couldn't get a support subscription with an eval copy.

"top levels working down (source codes, platform macros and other things) are looking the same or similar for most platforms" yes that's the impression I got.

Ok, so avoid the heap. I guess it's also a bit safer if all the memory is known and defined at compile time. Still not sure how to fix my ISTACK/IDATA_Z problem ( pt. 1) ) though, I presume there should be space for an array of more than 46 unsigned ints!

I presume then getting a book on the 8051 is not really that useful. I understand most of the 8051 have enhancements and any way you need to learn the dev environment nearly as much.

Thanks again, A.