When my laptop freezes, the Alt+PrtScrn+REISUB method of forcing a reboot or shutdown has never worked for me. I've tried all possible permutations, such as holding down the Fn key as well, using the SysRq key instead, holding down REISUB keys as long as possible, etc., but this method has never worked for me. No forced reboot or shutdown has ever happened on my laptop using the REISUB method. This has been over the last few years, and I've had various versions of Zorin on my laptop, and multiple experiences of crashes, and REISUB never works. So I end up forcing a shutdown by holding down the shut-off button, which I understand isn't good for the system. Can someone suggest why REISUB has never worked for me, and if there are any alternative ways to safely reboot or shutdown when my system freezes? I am also talking about situations when I can't open the terminal. I've searched on Google, but everyone just seems to recommend the REISUB method, yet obviously this is not helpful for me since this method has never worked for me.
This method would not have been applicable for quite a long time... Zorin OS uses the ext4 journaling, but any journald system would be ill-served by the above code.
If the terminal can be pulled up then
sudo shutdown –r
You can enter a TTY if the terminal will not launch. Much safer.
ctrl+alt+F1 to enter TTY and
ctrl+alt+F7 to exit TTY.
Use the above shutdown or reboot codes in TTY.
If you are insistent on using REISUB method, check the output of
Change this value to
sudo echo "1" > /proc/sys/kernel/sysrq
This can have some undesirable side effects. In order for it to work, it must detach the keyboard from X, for a start.
If your system freezes, meaning it stops processing or is stuck processing a specific routine, it will not respond to any other routine you are able to mash into it. That would require the system to process something other than what it is stuck on.
As much as we'd like to believe, computers are not multitasking... the switch between tasks faster as well as process things faster, it gives the illusion. Even multi threading is not multi tasking. Each thread is only doing one thing... they all take turns interacting with the os and hardware... again, faster than you can notice.