about niosII IDE system library property,

Currently the Nios II IDE can only create systems in a "boot from flash" rather than "run from flash" configuration. You can set the reset vector to point to flash, but the .text and .rodata sections must point to RAM.

Placing the reset vector in flash will cause a boot loader to be placed at the reset address which will load your code into the specified location in RAM, and run it.

If you want to "run from flash", i.e. place the .text and .rodata sections in flash there is a seperate thread on the General Software Forum, entitled "Run from Flash" where it's explained how to do it.

I hope that helps...