Boot Process (from this video): 1. Power supply sends power to the motherboard, which activates the boot process. 2. POST (Power On Self Test) instructions are stored in a ROM (Read Only Memory) chip, as part of the BIOS (Basic Input Output System). 3. The POST runs through series of tests to ensure that everything is working. 4. Most POST sequences will have a combination of audible and visual messages to let you know what is or isn’t working. These are the beeps you generally hear when the computer is booting up. 5. The POST checks your video card. At that point you will see information of the POST on the screen. 6. The POST send checks to make sure it can find the CPU and that it is communicating. 7. Then it checks your RAM. This is a very basic check of whether it can communicate with the RAM. 8. Now it checks for keyboards and mouse. Depending upon the type of keyboard you have, you might see the keyboard’s lights flash. At this point you would normally see an indication on the screen of how you could enter the BIOS setup program in your computer. Each BIOS software vendor would have a different keystroke, but it is often either F2, F10 or DEL. 9. Your computer can be set to boot from your hard drive, or from your CD or a USB drive or even from the network. 10. If you want to boot from a CD or a USB device, you may need to change the boot order. 11. Most computers are setup to check their optical drives first. This makes it easier during new installs of operating systems. 12. Then they check their first hard drive, drive 0. 13. POST is looking for the MBR (Master Boot Record). This is always at Cylinder 0, Head 0, Sector 1, or 0,0,1. It points to the Boot Sector. 14. Once the MBR is found, the control is passed from the POST to the Operating System referenced in the MBR.
I love how this person started posting drawing tutorials, decided to drop a quick, accurate, and easy-to-understand video on how POST functions, and then returned to posting drawing tutorials as if nothing happened
Dont know if you guys gives a shit but if you are stoned like me atm you can watch pretty much all the latest movies on instaflixxer. I've been streaming with my brother these days xD
The processor must be powered and work first for the program on the firmware (BIOS or UEFI) to run. Technically, the CPU is hard coded with a jump program that tells the processor where to find the UEFI.
memory acquisition and bypassing encryption are both strong digital forensic points to consider as these hardware based techniques can then give a lot of information away about a system!
What does a computer when you hit the power button? 🤔 Cpu and Chipset check configuration: is it authorized or not, if not, CPUs Minix OS with Intel ME softlock half of your PC features, I think that is what does a computer when you hit a power button, and yeah, bios is too, checking something - your holes, do they work or not😂
@@youcefslimani6352 post is power-on self-test. Your CPU basically does that after you powered it up to check everything will be fine or not and it will send you audio and video signals as well.
There's a couple mistakes in this video. I know you're probably an artist now and don't care about this anymore, but can you at least set it to private or unlisted so it's not spreading misinformation?
@@DeerJerky ok, I've done some research and I've come to the conclusion that I had some misconceptions about bios and post when I made that comment. I thought the post sequence was performed by a dedicated chip that was hardwired and not part of bios and that bios was performed by the cpu reading from the rom. Turns out none of that is true, so my bad
@@nanofinder actual props for honesty and replying, that's awesome to see nowadays But anyway, I totally get that. You were partially right, that POST was directed by a dedicated, hardwired chip of sorts, just that the chip is the BIOS and it technically can be overwritten (but not as easy as a quick windows update... usually). I'd say you easily had the right idea
Hello not sure if someone is gonna answer me (on this issue 6 years later😂) But still , Knowing that that's the CPU who runs any program of the computer, I was wondering what is running the post program since it's it who will be started first and as you said it will start and test all hardware components the CPU included Thanks for such an amazing video
Buzzword of the day 7 years ago from today; forensic. Ps. Post stands for Power On Self Test, it is routine script in bios. It has nothing to do with anything else. Bios reads boot configuration and other stuff from cmos, then acts on it. So, when you push power button, it shorts transistor that latches to keep psu sleep pin grounded. Then whole pc gets power, but since cpu has no instructions in pipeline, it goes into sleep state. Meanwhile, bios rom was powered too and it has stuff to do according to it's built in configuration that starts with checking cmos for config. Then it runs POST and does other stuff until it is satisfied and checks boot devices in order as configured in cmos. It then reads first 446 sectors from disk in hopes of finding 1st stage bootloader. If it finds it, then it relinquishes hardware control to cpu by sending reset command with appropriate instructions to load bootloader from bootmedia.
This video is about the importance of booting up your computer. It tells about the stages that a PC goes through when booting. It also talks about the ability to change the loading order, which may be useful for various government agencies.
bios performs POST, you can think of bios as a mini-operating system that is checking your PC (this process is called POST - power on self test) , establish communication between different components and boots an OS bootloader
@Excuse me Wth There isn’t much of a difference between BIOS and UEFI to the average consumer. Also UEFI uses POST to boot just like BIOS, and without post your computer will not boot an OS.
