Have you ever wondered what your computer goes through when it’s booting up each time you restart your computer? Sometimes computers will start up so quickly, but other times, they drag, don’t they? Well, every time a computer is booting up, it has to go through what is called a POST test. POST stands for Power On Self Test and it’s just a little personal start up test for every computer to make sure it meets all of the system requirements, etc.
There are actually 10 steps in the POST, with the first one testing the power supply to make sure the computer is turned on and that it meets its reset signal. The second step checks to make sure the CPU (Central Processing Unit) can execute instructions. The next two steps are used to ensure that the BIOS are readable.
Again, the next two steps are devoted to the CMOS (Complementary Metal-Oxide Semiconductor) to make sure they are readable. The seventh step tests the CPU to make sure it can read all the different forms of memory, like the memory controller, the memory bus and the memory module. Next, your computer’s memory is tested to make sure it is operational and that it can be read and written, as well as, capable of containing the POST code. The last two steps deal with the I/O bus and controller. They need to be accessible and be able to write and read from the video system and to read all of the video RAM.
If your computer happens to fail any of these steps, an irregular POST will be recorded. The irregular test is known to you by a beep code and it may often result in you having to restart your computer.
There you have it, the basic steps to a system start up test. At least you now know what your computer goes through while starting up and you have an idea of what might be going wrong if your computer ever fails a proper boot up.