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Old 09-01-2014, 01:58 AM   #1
displace
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How does GRUB2 know to display a menu upon boot?


Hi

I was wondering this for a long time. Suppose you have a linux distro installed like Ubuntu or some equivalent. The system will automatically boot to desktop without displaying any boot menus, but after hard reseting the PC, it will stop the booting procedure, and display the boot menu instead.

My question is how does GRUB2 know that the system has not been shut down properly?

Regards!
 
Old 09-01-2014, 02:28 PM   #2
jefro
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Pretty sure the menu is there always or at least in most cases. It has been not selected to show in cases where one distro is installed. Usually pressing the spacebar at some time in boot will cause the default menu to appear.
 
Old 09-01-2014, 02:53 PM   #3
EDDY1
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I would say because of orphaned inodes.
 
Old 09-01-2014, 05:14 PM   #4
displace
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The menu does not appear normally, the OS boots automatically, and a splash screen is displayed. The menu only appears when the computer has not been properly shut down. The thing is that my rootfs is encrypted, so it's not possible to read data from it, and it is decrypted only after the kernel has loaded/booted. that means after the GRUB stage. Another possibility is that it writes to the unencrypted boot partition. I did a sha1sum of the entire file tree, and it did not seem to change. Additionally I did a sha1sum of the first 2048 sectors that didn't change either.

I'm puzzled, I must have missed something.
 
Old 09-01-2014, 05:30 PM   #5
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But keep in mind that if improperly shutdown all of your previously mounted including where your the 1 that /etc/default/grub resides & grub hidden timeout on will go thru a fsck to find it / will be first. So grub is going to default to allowing acces to all tools. Which once selected grub does fsck.
 
Old 09-01-2014, 08:10 PM   #6
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http://forum.xbmc.org/showthread.php?tid=64857
 
  


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