When you turn on the power to your PC, the processor begins the boot by
initializing itself and then turning to
1. When the power is first turned on, the system clock begins to generate clock pulses.
2. The processor begins working and initializes itself.
The processor turns to memory address FFFF0h, which is the memory address
always assigned to the instruction in the
4. This instruction directs the processor to run post.
5. Post checks the BOIS program operating it and then tests CMOS RAM.
6. A test determines that there has been no battery failure.
7. hardware interrupts are disabled.
8. Test are run on the processor and it is initialized further.
9. A check determines if this is a cold boot, if so the first 16KB of Ram is tested.
10. Hardware devices installed on the computer are checked and compared to configuration information.
video card is tested and configured, during POST, before the processor has
checked the video system, beeps sometimes
12. Post checks RAM by writing and reading. The monitor displays a running count of RAM during this phase.
13. Next the keyboard is checked, and if you press and hold any keys at this point, an error occurs with some BOISs.
14. BIOS begins its search and loading OS.
So now you have a better understanding of what happens when you turn your