1

During the process of booting, CPU reads address of system BIOS from the Reset Vector and jumps to the location where BIOS is stored. My question here is:

  • As BIOS is stored on some external memory like EEPROM (and not in main memory), how does CPU access this external memory?

  • Is this external memory already mapped to some region of main memory? and does the CPU just jump to this mapped region to access BIOS instructions? Or it actually accesses the instructions from external memory where BIOS is stored?

Improve this question
1
  • "As BIOS is stored on some external memory like EEPROM (and not in main memory)" -- FYI the main memory is also "external" memory. The typical PC has RAM chips soldered on removable modules. Or do you have a special definition for "external"?
    – sawdust
    Commented Oct 9, 2015 at 7:33

1 Answer 1

Reset to default
1

BIOS is only another memory location as RAM.

CPUs are programmed to read an specific address location (the "reset vector") when they start, so in that location is where the BIOS EEPROM is located. It used to be 000FFFF0h.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .