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Anonymous5638
Asked: 2020-07-13 02:22:55 +0800 CST

SQUASHFS error: How to poweroff laptop?

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I created a bootable USB with Ubuntu 20.04 on it and I wanted to test it on a working Ubuntu 20.04 Laptop whether it works. This was apparently not a good idea, because I get dozens of SQUASHFS-errors and I cannot do anything at the moment (I pressed the on-off-button several times, but the laptop still won't turn off). I am pretty sure by now (since I already removed the flash drive and checked it on another computer) that the flash drive is corrupted.

This is not a huge problem, what does annoy me is that I cannot use my laptop. I cannot take the battery from the notebook (it isn't removable), so what can I do (it probably still has around 5 - 10 hours battery life-time, and I wouldn't mind having my laptop soon)?

boot usb battery

1 Answers

  1. Best Answer

    To tell the kernel to reboot you can use

    ALT+SysRq REISUB continue holding down ALT key as you type all letters

    From Wikipedia the REISUB the the kernel

    unRaw (take control of keyboard back from X),
tErminate (send SIGTERM to all processes, allowing them to terminate gracefully),
kIll (send SIGKILL to all processes except init, forcing them to terminate immediately),
Sync (flush data to disk),
Unmount (remount all filesystems read-only),
reBoot.

    To shutdown the machine instead of reboot, you can replace the B with a "O". All keystrokes are worth it to ensure a clean system (sync or flush buffers to disk & umount protecting data on your system prior to reboot or power-off. SysRq keys are far safer than trying to use the power-off or pulling a power cable on a box as the kernel can cleanly shutdown the system (or obey other commands, refer wikipedia page for clues)

    PS: I'd not recommend the Alt-SysRq + B as it won't leave a clean file system; REISUB is safer.

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