When a computer bots up, it follows a series of steps to initialize and start the operating system. Here's a general overview of the process:
1) Power-on Self Test (POST): When you turn on the computer, the power supply sends electrical signals to the motherboard. The CPU starts executing code form a fixed location in ROM(Read Only Memory) or flash memory. This code performs the POST, which check the hardware components (RAM, COU, storage devices, etc.) to ensure they are funcioning correctly
2)BIOS/UEFI Initilization: After POST, the BIOS(Basic input/Output System) or UEFI (Unified Extensible Firmware Interface) firmware is loaded. BIOS is the traditional firmware interface, while UEFI is a more modern version that suppoorts largeer hard drives and faster boot times. The BIOS/UEFI provides a low-level interface between the operating system and the hardware
3)Boot Device Selection: The BIOS/UEFI looks for a boot device based on a predefined order(eg: HDD, SSD, USB, CD/DVD). IT searhces for a bootloader on the seleceted device
4)BootLoader Execution: The bootloader is a small program responsible for loading the operating system for example (GRUB) Grand Unified Bootloader is commonly used in Linux Systems, while the Windows Boot manager is Windows systems. The bootloader initializes the system and loads the operating system kernel into memory
5)Operating System Initializatino: Once the kernel is loaded, it takes control of the system. The operating system initializes system components, manages hardware resources, and starts system services and background processes
6)User Login: Finally, the operating system presents the user with a login screen or desktop environment, depending on the system configuration. The user can then interact wiht the computer and urn applicatios.
