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Thread: Emergency Shutdown?

  1. #11
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    Re: Emergency Shutdown?

    Hi

    Quote Originally Posted by Grenage View Post
    While I've only used this once, I assume you can use the commands in any sequence, or in isolation?
    Yes you can but this combination is the closest to a normal shutdown.

    For example, to write cached data, could one simply press alt-sysrq-s?
    Yes you can but in normal OS operation you should not need to.

    The Wikipedia link i posted above has a list of them.

    Kind regards
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    If you don't read the newspaper, you're uninformed. If you read the newspaper, you're mis-informed. - Mark Twain

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  2. #12
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    Ubuntu 11.10 Oneiric Ocelot

    Re: Emergency Shutdown?

    Quote Originally Posted by matt_symes View Post
    Hi



    Yes you can but this combination is the closest to a normal shutdown.



    Yes you can but in normal OS operation you should not need to.

    The Wikipedia link i posted above has a list of them.

    Kind regards
    Excellent, thank you.

  3. #13
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    Ubuntu Development Release

    Re: Emergency Shutdown?

    The keyboard I am using has a key with a Print Screen label. I have two older keyboards where this key is called Prt Sc Sys Rq. I think I can assume that the print screen key is also the system request key even if it is not labeled that way.

    Regards.
    It is a machine. It is more stupid than we are. It will not stop us from doing stupid things.
    Ubuntu user #33,200. Linux user #530,530


  4. #14
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    Re: Emergency Shutdown?

    Hi

    The keyboard I am using has a key with a Print Screen label. I have two older keyboards where this key is called Prt Sc Sys Rq. I think I can assume that the print screen key is also the system request key even if it is not labeled that way.
    Maybe not. Some keyboards do not have it. Your best bet is to try it as long as it's not on a production machine.

    You cannot remap it using xmodmap either (as far as i am aware). It is compiled into the kernel and requires the CONFIG_MAGIC_SYSRQ (last time i checked) macro to be enabled.

    You can check if it's compilied in and enabled if the command below returns one and the file exists.

    Code:
    cat /proc/sys/kernel/sysrq
    Code:
    matthew@matthew-laptop:~$ cat /proc/sys/kernel/sysrq 
    1
    matthew@matthew-laptop:~$
    On Ubuntu it seems to be enabled by default on desktops. Will check my server and other distros at some point.

    Not a good idea to have it enabled on a production machine. It can be disabled with...

    Code:
    sudo sh -c "echo 0 > /proc/sys/kernel/sysrq"
    Obviously this (echo 0 > /proc/sys/kernel/sysrq) can be added to a configuration file at startup.

    ..or one can recompile the kernel.

    Kind regards
    Last edited by matt_symes; March 9th, 2011 at 03:56 PM.
    If you believe everything you read, you better not read. ~ Japanese Proverb

    If you don't read the newspaper, you're uninformed. If you read the newspaper, you're mis-informed. - Mark Twain

    Thinking about becoming an Ubuntu Member?

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