UEFI (Unified Extensible Firmware Interface) is a mini operating system that loads the bootloader in the memory before it executes additional operational routines. The evolving requirements of computer users have led to the creation of a modern successor to BIOS. The bootloader is usually composed of three programs:Ī boot sector program directly loaded by the BIOS at boot timeĪ second stage program loaded by the boot sector program to complete the booting processĪ bootloader installer to install the bootloader and the second stage program in the boot disk. The main BIOS may start the extension ROMs. In addition to the BIOS, there are extension ROMs. Not all operating systems use BIOS interrupts.

Related: How to Access BIOS On A Windows 8 ComputerīIOS interrupts are device drivers relied on by bootloaders to access the screen, keyboard, and disks. It is needed for the first available memory block or sector in the medium to be reserved for the record. The boot sector loader loads the first 512-byte sector from the boot disk into RAM. This includes the boot order, which determines the devices the BIOS checks before booting. Modern BIOS versions are used to set different parameters. The Setup Menu helps to adjust the parameters of the bootloader. When the PC is turned on, the BIOS runs before any other program runs. The key components of a bootloader include the basic input/output system (BIOS), firmware found in the Read-Only Memory (ROM) of a PC. It is needed to run the startup process, initialize the hardware, and pass control to the kernel, which initializes the operating system. This means that there are no programs in its memory and that its components cannot be accessed.Ī bootloader helps to load the operating system or runtime environment to add programs to memory and provide access for components. When turned on, a computer has a clear state. If you're interested in learning about what a bootloader is and how it works, this article is for you. This article explains what a bootloader is and how it works. This is because it plays its role in the background, helping to activate the correct operating system. Most of the processor boards in our devices have programs pre-loaded on them. Yet, it is often overlooked as a key component of computers. A bootloader is very important for operating systems.

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