detecting memory-mapped i/o peripheral in OS

hi all,

         can any explain function of bootloader, and how linux or
other OS detects the external pheripherals on an x86 processor(80486).

2. which will create GDT,LDT,IDT in system linux or BIOS or boot
loader.

3. if  added new peripheral which is memory mapped in to the system
address space(memory-mapped i/o) :

          how can i see the pheripheral in linux or other os, for this
do i need to edit any GDT, LDT or IDT in boot loader, or OS will do
this job.


4. can any suggest me the book which explians porting concepts fully,
so, that i can able to port linux or other OS on my custom hardware
which has variety of pheripherals memory mapped or io mapped.


thanx in advance..

Bhanu prakash

>         can any explain function of bootloader, and how linux or
>other OS detects the external pheripherals on an x86 processor(80486).
>   ....

Umm, the best way is to download the source to Linux and look at the code. I
would suggest getting a Linux Internals book like "Understanding the Linux
Kernel" from O'Reilly. It explains the Linux 2.4 kernel from the point of view
of an x86 system.