#When you forget root password, there is a way to set a new password accessing the console after booting or restarting the system.
When grub load, edit the line kernel and add in the end of kernel parameters:
init=/bin/bash
The system will go up without requesting root password like in single user.
After the system is up, re-mount / filesystem
# mount -o remount,rw /
Now the / filesystem is accesible and you can change root password with:
# passwd root
Now reboot the machine Read more...
Linux
Linux stuff
#to copy or backup the MBR
MBR information is stored on the first 446 bytes of a disk, to backup this information you can save it with dd to another disk, or to a file.
dd if=/dev/sda of=/dev/sdg bs=446 count=1
dd if=/dev/sda of=/path/to/a/file.mbr bs=446 count=1
To restore the data to its original place using our backup file:
dd if=/path/to/a/file.mbr of=/dev/sda count=1