Difference between bootloader and bootloader?
how the bootloader differs from the bootloader. According to my words, the bootloaders are loaded in ROM and the bootloaders are located on the hard drive in the MBR (please correct me if I am wrong). bootstrap loader is the first program to run after startup. Now I don't understand the meaning of these sentences: After power-up, the bootloader controls the board and does not rely on the linux kernel in any way. And also the bootloader acts like glue between the bootloader and the Linux kernel. what does it mean? And why do we demand both of them?
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Many architectures use a boot loader or second level loader to load a Linux kernel image into memory. Some boot loaders perform checksum checks on the kernel image, and most of them perform kernel image decompression and relocation.
The difference between a bootloader and a bootloader in this context is simple: the bootloader controls the board at power-up and does not rely on the Linux kernel in any way. In contrast, the main job of a boot loader in life is to act like glue between the board-level boot loader and the Linux kernel. It is the responsibility of the bootstrap loader to provide the proper context for starting the kernel, and to take the necessary steps to unpack and move the kernel binary image.
Alternatively, called a boot, boot loader, or boot program, a boot loader is a program that resides on computers with EPROMs, ROMs, or other non-volatile memory that is automatically started by the processor when the computer is turned on. The boot loader reads the boot sector of the hard drives to continue the boot process of the computers operating system. The term boostrap comes from the old phrase "Pull yourself up by your bootstrap". The boot loader has been superseded on computers with Extensible Firmware Interface (EFI). A boot loader is now part of the EFI BIOS.
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Bootstrap Loader
Alternatively, called bootloader, bootloader or bootloader, bootloader is a program that resides on an EPROM, ROM, or other non-volatile memory on the computer. It is automatically executed by the processor when the computer is turned on. (Come from WIKI)
You may think it will turn on right after power on and this is part of the BIOS (BIOS has many other features like providing some diagnostic output and allowing the user to customize the hardware) Note, in some cases Bootstrap Loader can also be called a loader or boot device ... -
Bootloader
A boot loader is a piece of code that runs before any operating system starts up. A boot loader is used to boot other operating systems, usually each operating system has a set of specific boot loaders. (Come from google)
HERE STEP
0 : Power On!
1 : CPU Power On! CPU try to find something in ROM(Or ERROM)
2 : Find BIOS (or other firmware). Run BIOS
3 : BIOS(bootstrap loader and other functions) run
4 : BIOS try to find something in MBR
5 : Find MBR(512 bytes) there is some useful information of the partition
6 : Copy the MBR content into physical disk 0x7c00 where is the location of the Grub.
7 : Grub(a type of bootloader) use the information of the MBR finds a linux! Prepare to run.
8 : Run your linux!
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A boot loader such as U-Boot or RedBoot takes control of the hardware as soon as it is turned on. On the other hand, the Boostrap loader attaches itself to the sample core to prepare a suitable context for starting the core. For example, when compiling a kernel for ARM architecture, the kernel file will be compiled as a file piggy.o
, and the boostrap bootloader files will be misc.o
, big_endian.o
and head.o
.
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