Managing and updating your bios
The first thing the BIOS does is check the information stored in a tiny (64 bytes) amount of RAM located on a complementary metal oxide semiconductor (CMOS) chip.The CMOS Setup provides detailed information particular to your system and can be altered as your system changes.For example, when you press a key on your keyboard, the signal is sent to the keyboard interrupt handler, which tells the CPU what it is and passes it on to the operating system.The device drivers are other pieces of software that identify the base hardware components such as keyboard, mouse, hard drive and floppy drive.Boot refers to the process of launching the operating system.The BIOS will try to initiate the boot sequence from the first device.It checks the PS/2 ports or USB ports for a keyboard and a mouse.It looks for a peripheral component interconnect (PCI) bus and, if it finds one, checks all the PCI cards.
Interrupt handlers are small pieces of software that act as translators between the hardware components and the operating system.
Since the BIOS is constantly intercepting signals to and from the hardware, it is usually copied, or shadowed, into RAM to run faster.
Whenever you turn on your computer, the first thing you see is the BIOS software doing its thing, which is the Power On Self Test, shortened to POST.
If the BIOS finds any errors during the POST, it will notify you by a series of beeps or a text message displayed on the screen.
An error at this point is almost always a hardware problem.