Some of this was answered in my response to your previous question.
More info on linker scripts can be found at
http://sourceware.org/binutils/docs-2.18/ld/index.html
Note: any space not being used by your program code, static variables,
stack, etc can be used for your purposes - no need to tell the linker
(though you certainly can if you want to - has some advantages in that
the linker can verify that your buffers and your code have enough space
to coexist in RAM, but again, not essential to do).
Dan
--
Daniel Foisy
Virtual Cogs Embedded Systems Inc.
Unit 4, 5694 Highway 7 East, Suite 311
Markham, Ontario, Canada L3P 1B4
www.virtualcogs.com
416-238-2231
"Your future is modular"