Initialize network & peripherals and search for executable code in first sector of define & detected.
First 512 byte of disk MBR programmed takes 446 byte partition table &66 byte grub take change loads Linux kernel.
Kernel detects network and peripheral loads hardware drivers and than gives its control to to the limit.
Init is the master of a UNIX system. Init a certain run level from /etc/init .
After init all the run level will come it is the place where the login prompt will come and we want .