From the course: CompTIA A+ Core 1 (220-1101) Cert Prep

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Power-on self-test (POST)

Power-on self-test (POST)

From the course: CompTIA A+ Core 1 (220-1101) Cert Prep

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Power-on self-test (POST)

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- Have you ever noticed that there's no run button on a computer? I mean, sure there's a on-and-off button, but the only thing the on-and-off button does is provides electricity to the computer. If you got to think about this, there has to be something that says "CPU, start running programming." And that's done by the CPU itself. Built into the back of every CPU is one little wire called the Power Good Wire. And as soon as that one wire gets enough voltage, the CPU starts running and the first thing it's going to do is it's going to go talk to the BIOS and it's going to run a little piece of BIOS known as the Power-On Self-Test, or POST. Now the Power-On Self-Test is actually a pretty simple program. It kind of broadcasts out throughout the motherboard. It says, "If you can hear me, check yourself out." So all of the memory controllers and your RAM and USB controllers and hard drive controllers and whatever you might have on your motherboard goes through its own internal diagnostic…

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