Monday, February 09, 2009

Confessions of a 'Ctrl-Alt-Del' Addict

Growing up in a world where MS-DOS was the first operating system I've ever used certainly leaves me rather brain-damaged when it comes to the 3-finger salute of 'Ctrl-Alt-Del'. That key combination literally is the 'One Keystroke That Rules Them All' - more or less, it's the last thing that will probably still work in the face of a catastrophic computer failure.

Obviously, I never did wean off from my un-elite MS heritage, so it should come as no surprise that I sometimes still use 'Ctrl-Alt-Del' to solve my problems in Linux. Still, it's nice to know that Linux on the whole has always been accommodating enough to include that magic keystroke to satisfy the likes of people like me - most distributions secretly sneak in a line in /etc/inittab (or /etc/event.d for Ubuntu's Upstart) to make it reboot should I fancy myself into fondling those keys when my urge arises, although I must say I have less urges to do so these days ever since I've migrated to Linux, so thanks for asking!

Even when in graphical mode (it's called 'X-Windows' by the way, but you can simply call it 'X' if you want to be a smarty pants, but calling it 'Windows' is plainly an insult!), most window-managers still associate it with some behaviour, like invoking 'xkill' or popup for a shutdown menu. I think some window-managers even invoke the screensaver for that! (I don't even want to go there - that's just plain wierd!)

Shame to say, I've only recently discovered the equivalent of 'Ctrl-Alt-Del' in the Linux world after using it for 8 years!

The magic keys are known as 'System Request' (Sysreq) keys, the all powerful keystrokes a man can invoke (then pray) if your system ever gets f**ked or becomes totally unresponsive. Before you even hit the power switch, try holding down the 'Alt-PrintScreen' keys, and type in the following letters: r-s-e-i-u-b

A good way to remember it is by the phrase:

"Reboot System Even If Utterly Borked"

With luck, that will try to kill all processes gracefully, sync all data to your drives, unmount them, and reboot your system. There's more to the Magic Sysreq keys than I have let on, and more details can be found here.

There are a few other neat tricks with the Sysreq keys, like killing off errant applications that's chewing off too much of your system memory with 'Alt-PrintScreen' + r-f.

A pity that I've only learnt it after such a long while, for it would have been really helpful when I was tearing my hair off a while ago when Rubygems was chewing up all my free memory and thrashing my harddisk from all that silly swapping.


Anonymous said...

Actually, the correct sequence should be:
R - E - I - S - U - B

You can remember this by typing the word "busier" backwards.


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