The BIOS - CompTIA A+ 220-1201 - 3.5

When you start your computer, you may notice that the information you're seeing on your screen is not related to the operating system that ultimately loads. What you're seeing on the screen is the BIOS, the basic input output system of your computer. You might also see this referred to as the firmware of your system. And some people refer to

this as the system BIOS or ROM BIOS, which is referring to read only memory. These days, we don't generally use read only memory to store the BIOS software. Instead, it's usually stored on your motherboard in flash memory. The BIOS is responsible for initializing your system and getting everything ready to run with the operating system that you need to

load. The process you see when you start your computer is referred to as the power on self- test or post. This checks for a CPU, make sure that you have memory installed in the system, that a keyboard and a mouse is connected. And if there are any problems initializing those core systems, you'll see an error

message on your screen. This process only takes a few seconds, and once this diagnostic is done, it begins to start your operating system. This may begin immediately loading your operating system, or you may receive a prompt requesting you to choose which operating system you'd like to use. This prompt is the bootloadader and it signifies that

you've completed the post and is now ready to load the operating system. As we mentioned earlier, this BIOS software that starts your system is usually stored in flash memory on your motherboard. And if you look closely at your motherboard, it's probably even marked. On this motherboard, there are two separate BIOS flash chips, one that