Who loads the code in BIOS during booting?

I am studying the boot process in Linux. I am looking through this html page http://www.tldp.org/HOWTO/Bootdisk-HOWTO/x88.html. The first line under the section 3.1 "The boot process" says that "All PC systems start the boot process by executing co开发者_C百科de in ROM (specifically, the BIOS)".

My doubts are

1. Who loads the code in BIOS ?

2. Where is this code in BIOS located ?

3. To where is the code in BIOS loaded and executed ?

Kindly tell me references where i can get more information

Thanks, LinuxPenseur

The code is already there in memory when the computer is powered on. It is in non volatile memory, meaning it doesn't disappear when the computer is turned off.

So the code is already there in a specific memory address, and the processor starts by running it.

More info here

A good question! Actually you do not need to reformat the HDD or even reinstall the OS on it unless the new PC is unable to run the existing OS on the drive.

Commonly, if you did a simple install of a Linux distribution, you would have no trouble moving the HDD to a new system and just running it. But if the OS is a version of Windows, the chances of this being the case are nearly zero: hardware vendors nearly always tune their device drivers for Windows so you cannot even use the same driver for two versions of Windows on the same machine (upgrading from XP to Windows 7 for example, often requires that you redownload at least a few hardware drivers).

And the problem often arises even with Linux if you have installed any high performance drivers. Sometimes you can perform a "recovery boot" from GRUB or LILO and get into a text mode screen with internet access, though. And if you can do that, often you can install the drivers for the new PC on the Linux HDD without doing a complete reinstall of Linux.

In fact, this is actually what that install CD or DVD is actually doing. It boots to a very vanilla flavor of the OS (Windows or Linux), then installs drivers for the hardware it detects, reboots (hopefully with functioning drivers) and wraps up the install process.