I am reading this article, How does system bootstrap, according to it:
The BIOS then looks for other devices' ROMs to see if any of them have BIOSes. Normally, the IDE/ATA hard disk BIOS will be found at C8000h and executed. If any other device BIOSes are found, they are executed as well.
I know that the so called main BIOS is stored on BIOS chip, but where are the device BIOSs, are they stored on device controllers ?And how does main BIOS detect device BIOSs ?