what is the concept of memory models with regard to embedded C? i read the section in keil online manual,is there a bit more digestable explanation about it?
"what is the concept of memory models with regard to embedded C?"
There is no general tern "memory model" that is universally applicable to embedded 'C'.
Keil use the term with the specific meaning defined in their Documentation: http://www.keil.com/support/man/docs/c51/c51_le_memmodels.htm
Other contexts may use the term with an entirely different meaning!