How a Computer Works

How a computer works…well, my knowledge and understanding here is very limited, but here it goes:

When you press the "On" button on the computer and the monitor, you begin to see the BIOS software doing its job. It begins by doing the power-on self-test (POST). On many machines, the BIOS displays text describing data ,such as the amount of memory installed in your computer and the type of hard disk you have. During this boot sequence, the BIOS does a lot of work to get the computer ready to run.

First, the BIOS determines whether the video card is operational. Next, the BIOS checks to see if this is a cold boot or a reboot. If it is a cold boot, the BIOS verifies RAM by performing a read/write test of each memory address. It also checks for a keyboard and a mouse, and any expansion cards that may be connected. If the BIOS finds any errors during the POST, it tells you with a series of beeps (I just found this out a few weeks ago when I was troubleshooting a problem with one of my computers),or a written message displayed on the screen. An error found at this point is almost always a hardware problem.

If it is a cold boot, the BIOS verifies RAM by performing a read/write test of each memory address. It also checks for a keyboard and a mouse, and any expansion cards that may be connected. If the BIOS finds any errors during the POST, it tells you with a series of beeps (I just found this out a few weeks ago when I was troubleshooting a problem with one of my computers),or a written message displayed on the screen. An error found at this point is almost always a hardware problem. The BIOS displays some details about your system. This typically includes information about the processor, floppy and hard drive, and memory.

Finally, BIOS launces the Operating System (OS), commonly referred to as boot (short for bootstrap loader).
The bootstrap loader loads the operating system into memory and allows it to begin it function. Now the BIOS turns the work over to the Operating System.

To be continued...