Power - On Self - Test (POST)

1. Switch on your PC, start a process called the POST ( power-on self test ) From CPU.

2. The CPU uses the address to find and invoke the ROM BIOS boot program, which is a series of system checks. The CPU first checks itself and the POST program.

3. The CPU sends signals over the system bus. The circuits that connect all the components with each other, to make sure that they are all functioning.

4. The CPU also checks the system’s timer, or clock, which is responsible for make sure all the PC’s operations function in a synchronized.

5. The POST tests the memory contained on the display adapter and the video that control the display.

6. The POST runs a series of tests to ensure that the RAM functioning properly.

7. The CPU verifies that the keyboard is attached properly and determines whether any keys have been pressed.

8. The POST sends signals over paths on the bus to the floppy/ hard disk drives and which drives are available for OS.