Well, shutting down your computer is a very common thing. We have been doing this for some hundreds and thousands of times over the years with different operating systems too. And for the fun-loving, there actually are a number of ways in which you can shut down your computer. Like say, you can shutdown your computer remotely, setup a shutdown timer and so on. But did you ever think what happens after you ask your computer to shutdown?
Actually the process involved in this very small operation is quite tricky and complex. So we have decided to come up with this article to take you one step deeper into the nuts and bolts of a computer. And don’t worry we did put in a lot of efforts into this article to keep it plain (without lots of jargon) and easy to understand.
The Start-Up or Boot Operation:
First of all, to make the article complete we start our discussion right from when you press the power button. So this is what happens after a user presses the power button of the computer.
- After pressing the power button, first the firmware initiates and checks for all of it settings. This is actually a pre-boot session and the process ends once it detects a valid system disk.
- Then the firmware starts up the computer hardware and simultaneously reads the master boot record (MBR) and starts applications which help to load the operating system (like bootmgr.exe which then starts Winload.exe).
- The above two steps are the preliminaries the computer takes care of before loading the operating system.
- As soon as all the essential drivers are loaded, the Windows Kernel starts up and gets all those start-up applications to load along with it and makes the computer ready for the user.
- Once all this is done, the computer requests the user to log in and the user provides his username. Based on this username-password combination, the computer reads all the setting the user has pre-defined and loads all the other applications present in BOOT_START. Along with that, it also prepares the environment so that the user can start working.
To conclude the startup operation in one sentence you can simply quote that during the start-up three main processes occur: Hardware Initialization, Operating System Loading and Preparation of user’s environment.
The Shutdown Operation:
As you can imagine the shutdown operation is exactly the reverse of the booting or startup operation. But for your better understanding we have listed down all the steps involved in which it happens:
- Once the user initiates the shutdown process by selecting the shutdown option. (It can be done in many ways and we will surely discuss about it in our later articles in detail).
- The Operating System informs about this to all the running applications. It also provides some time to all these to quickly save their data. In certain cases if the application is not capable of completing this process fast the operating system also has the ability to provide a little extra time and ask the user if to close the application instantaneously or wait for it to complete its process.
- Next, it closes all the user accounts that are logged in earlier by the user.
- Now it broadcasts messages to all the services informing them a shutdown operation has began and in parallel shuts them down.
- Then it broadcasts the same message to all the connected devices and stops them.
- When all this is done, the operating system throws all the remaining data into the system disk and ensures it is saved.
- Finally with the help of the ACPI interface, it manages to power down the computer.
These are all the steps your computer goes through when you ask for it to shutdown. But note that this process was possible in the computers which were powered by the operating system versions prior to the Windows 8. But the Windows 8 operating system has managed to chop down few seconds both while starting up and during the shutdown. And this technology is named as the Hybrid Shutdown technology.
ALSO SEE: Windows Hybrid Shutdown Technology