On Sun, Mar 4, 2012 at 2:46 AM, beyond.hack <beyond.hack@xxxxxxxxx> wrote: > *** when bootloader in bios executes its code, it do POST and other > things...then as I read from somewhere kernel does initrd to load some > basic modules so as to mount the root file system and then removes the > initrd fs..... > (srry my mistake) > _______________________________________________ > Kernelnewbies mailing list > Kernelnewbies@xxxxxxxxxxxxxxxxx > http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies > Quoting from Understanding the Linux Kernel: The LILO boot loader is too large to fit into a single sector, thus it is broken into two parts. The MBR or the partition boot sector includes a small boot loader, which is loaded into RAM starting from address 0x00007c00 by the BIOS. This small program moves itself to the address 0x00096a00, sets up the Real Mode stack (ranging from 0x00098000 to 0x000969ff), loads the second part of the LILO boot loader into RAM starting from address 0x00096c00, and jumps into it. The LILO boot loader, which relies on BIOS routines, performs essentially the following operations: 1. Invokes a BIOS procedure to display a "Loading" message. 2. Invokes a BIOS procedure to load an initial portion of the kernel image from disk: the first 512 bytes of the kernel image are put in RAM at address 0x00090000, while the code of the setup( ) function is put in RAM starting from address 0x00090200. 3. Invokes a BIOS procedure to load the rest of the kernel image from disk and puts the image in RAM starting from either low address 0x00010000 (for small kernel images compiled with make zImage) or high address 0x00100000 (for big kernel images compiled with make bzImage). We say that the kernel image is "loaded low" or "loaded high" in RAM, respectively. 4. Jumps to the setup( ) code. So, you see the init routine is run only after the kernel has been loaded in RAM. -- Manavendra Nath Manav _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
