Re: bootloader-bios interaction

From: du (duqiang2050_at_sohu.com)
Date: 11/21/04 

Date: Sun, 21 Nov 2004 21:11:27 +0800

"Uday Mullangi" <udaymullangi@lucent.com>
> Hi,
>
> I am looking for the boot sequence for Linux OS (Intel P4 processor)
> In particular, where the BIOS finisies the POST and jumps to the
predefined
> location where the bootloader code is executed. I believe while the BIOS
is
> running the processor is configured in real mode. So when the bootloader
> code is executing, will the processor switch to protected mode?( i am not

No,bootloader running in real mode then it do not load the whole kernel
image.
Bootloader only load part of kernel,and jump to it.
In the kernel ,there is a asm function named setup() switch the processor to
protected mode and call startup_32().The startup_32 do something and load
other
part of kernel image

> sure). If the processor runs the bootloader in real mode then it can see
> only 1MB of RAM. In this case if the linux image is greater than 1MB how
can
> it uncompress the image?
> Could anyone give me some pointers about this execution ??
>
> Thanks
> Uday
>
>

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