Troubleshooting during LINUX Startup

Troubleshooting of the LINUX Startup Process-general Linux technology-Linux technology and application information. The following is a detailed description. Sector disorder:
1) if the root directory is not damaged
Assume that the disk block with an error is/dev/hda7, which is maintained by the root user on a single machine, and then input fsck/dev/hda7. Then, the screen displays information about starting disk repair, after the repair is complete, restart with reboot.

2) If the root directory breaks down
Unplug the hard disk and connect it to another LINUX system. You can fix the problem. Alternatively, use live cd to access the LINUX system and fix the problem.

3) The entire hard disk crashes.
Only one change is allowed

Forget the root password:
First, enter the single-user maintenance mode.
Find the/etc/shadow file
Use chmod to change the attributes of this file and make it writable.
Open the shadow file and delete the root password.
Restart. Do not use a password or a space to log on to the root user.
Finally, change the properties of the shadow file back, because it is not safe.