Size of RAM needed to store NiosII code

Thanks dsl, the window explorer file size indeed includes a lot of stuff that isn't loaded.

As for the stack and heap,

I did a test by comparing the size of the program with 2 different hardware build in SOPC, one with on-chip memory and another with sram:

http://i446.photobucket.com/albums/qq183/ahhbeng/SRAMonchip.png

I believe the stack+heap reported here indicates the free space available on the memory, so on-chip memory version reports 12KB, while sram version reports much larger free space, 4060KB.