General :: Control The Segment Selector Assigned To A Section?

I see from dumping executables that seg selector 0x10 is assigned to my stack segment and to my data segments (.bss .data COMMON). The code is using 0x08. My question - how can I control this? I've looked at all the command line options and don't see it. I have a different program that uses 0x10 for code and 0x18 for data. I note that the second program has i386 in the architecture field in the linker script, whereas the first one referenced has i686. Is this what causes the difference? I understand that this architecture field triggers something regarding a library named BFD - is this where I should look? If so, where do I find it? I am runnig fedora. Is there a way to control the association of sections in the linker script with segment registers? I can set up segments in the gdt and can asign them to segment registers. I can - when writing in assembler - assign code to a section. I can relate a segment in the gdt with a register.But I dont see how to tell the section which segment register it is associated with Finally I see that the gcc compiler decides - based on how I initialize a variable - whether to put it into bss or data or COMMON. Do I have any control over this?