Difference between bootloader and bootstrap loader?
how boot loader is different from bootstrap loader. According to me bootstrap loaders are stored in ROM and boot loaders are in hard disk in MBR (please correct me if I am wrong). bootstrap loader is the first program which get executed after startup. Now I am not getting the meaning of these sentences:- After power on , the bootloader is controlling the board and does not rely on the linux kernel on any way. And The bootstrap loader acts as a glue between the bootloader and the linux kernel. what these mean? And why we require both of them?
Answer
Bootstrap Loader
Alternatively referred to as bootstrapping, bootloader, or boot program, a bootstrap loader is a program that resides in the computer's EPROM, ROM, or other non-volatile memory. It is automatically executed by the processor when turning on the computer. (Come from WIKI)
You can think it will turn on immediately after power on, and it's part of the BIOS(BIOS has many other functions such as providing some diagnostic output, and providing a way for the user to configure the hardware) Pay attention, in some situation Bootstrap Loader can also be called as bootloader or bootstrap...Bootloader
Bootloader is a piece of code that runs before any operating system is running. Bootloader are used to boot other operating systems, usually each operating system has a set of bootloaders specific for it. (Come from google)
HERE IS THE 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!