When you restart a PC, does it completely “shut down”? If it does, what tells it to power up again? If it doesn’t, why does it behave like it has been shut down?
In: Technology
So I understand how the physical power button works on old PC’s to turn a computer on — it actually made a physical connection to enable power.
But on a MacBook for example, you hold down the power key on the keyboard for a few seconds, which is totally different.
I assume that whenever the laptop is even slightly charged, or always when it’s plugged in, some part of it is always on “a little bit” to detect pressing the power key?
There is additional story on software side of things.
For shutdown, Windows, for example, uses hibernation (save to disk) for a lot of kernel code instead of tearing it down, to speed-up next startup.
But for restart Windows makes complete teardown and rebuild of all kernel structures, because you usually request restart for updates and configurations, it’s not a part of normal operation.
[More info](https://www.howtogeek.com/349114/shutting-down-doesnt-fully-shut-down-windows-10-but-restarting-it-does/)
ELI5 answer
When you restart a PC, it does not shut down completely.
Someone used a metaphor for a chef so I’ll use that too. Shutting down completely would be like if the chef cleaned up and went home. Holding the power button down to shut down faster would be like if the chef didn’t clean up and just left a mess and went home.
Restarting the computer is telling the chef to clean up everything and then set everything back up without him leaving the building. So, it’s not totally “shut off” in that sense because the chef is still there to set things back up, and he knew that was the plan in advance!
##Note
**Shutting Down Doesn’t Fully Shut Down Windows 10 (But Restarting Does)**
https://www.howtogeek.com/349114/shutting-down-doesnt-fully-shut-down-windows-10-but-restarting-it-does/
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