when the computer is turned on for the first time, how does the operating system gets loaded from the hard disk to the ram? cause the o/s permits the programs to get booted but if the o/s is also in the hard disk, who permits it to be booted?
In: Technology
Fun fact: “booting” was named such because it’s when the computer picks itself up by its bootstraps.
When you first make a computer from scratch, there is nothing in storage, however it has a small computer in the motherboard that acts as a Basic Input Output System. The BIOS allows you to change settings on the hardware, and also launch boot drives.
So you plug in a USB/CD with the OS inside and the BIOS will recognise this as something that could run. So you just choose it in the BIOS, and then you’ll start running the program on the drive.
Some security OS’ can run completely off of a USB drive, so you don’t leave traces of what you did on the computer. However windows will send you to an installer program, which will move the files to the main storage so you don’t need the drive.
When powered on, the processor is hard wired to start executing instructions at a specific address. The bios/efi is placed at that address, and is what determines what drive to read the OS from.
The BIOS/UEFI’s bootloader.
It’s very basic, just as in the name, but it’s enough to start a more complex bootloader such as GRUB or the Windows BL.
The whole thing is wired to work this way, the processor first starts that primary basic bootloader, then it’s all just code. All the way from Assembly to Python.
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