Linux boot system and troubleshooting

One: Linux startup process:

Power-on self-test-"mbr boot (446 bytes loader, partition list 64 bytes, Magic 2 bytes)-" Grub menu (MBR is Grub's first field, second field exists in/boot/grub/)--"Load kernel kernel-" -"Start the first process init--" Find the initialization script/etc/inittab, this file has the default level--"Find the level-related startup script (such as/etc/rc.d/rc.sysinit, then find Level 3, read/etc/rc3.d)-" Boot script (/etc/rc.d/rc.local)--"Start the Mingetty process (through Mingetty generation terminal)

Two: Analog failure

Simulate master boot record MBR failure, how to troubleshoot

1:[root@lyt ~]# dd If=/dev/zero of=/dev/sda bs=446 count=1 #dd function is to copy a file with a specified size block, and to refer to it at the same time as a copy.

A fixed conversion. Dev/zero, is an input device that can be used to initialize files, BS is bytes,446 is the size of the MBR, the number of count=1.

2:[root@lyt ~]# Init 6 #将系统重启 to observe the startup results. The system cannot be as shown

3: After the boot input Linux rescue into the first aid mode, as shown:

4: Select the language, as shown in